5 This tutorial is supposed to give a first introduction for users
6 trying to do something real with GNUnet. Installation and
7 configuration are specifically outside of the scope of this tutorial.
8 Instead, we start by briefly checking that the installation works, and
9 then dive into uncomplicated, concrete practical things that can be done
10 with the framework provided by GNUnet.
12 In short, this chapter of the ``GNUnet Reference Documentation'' will
13 show you how to use the various peer-to-peer applications of the
15 As GNUnet evolves, we will add new sections for the various
16 applications that are being created.
18 Comments on the content of this chapter, and extensions of it are
23 * Start and stop GNUnet::
24 * First steps - Using the GNU Name System::
25 * First steps - Using GNUnet Conversation::
26 * First steps - Using the GNUnet VPN::
28 * The GNU Name System::
29 * reclaimID Identity Provider::
30 * Using the Virtual Public Network::
33 @node Start and stop GNUnet
34 @section Start and stop GNUnet
36 Prior to using any GNUnet-based application, one has to start a node:
39 $ gnunet-arm -s -l gnunet.log
48 @node First steps - Using the GNU Name System
49 @section First steps - Using the GNU Name System
57 * Resolving GNS records::
58 * Integration with Browsers::
59 * Creating a Business Card::
61 * Backup of Identities and Egos::
67 @subsection Preliminaries
70 ``.pin'' is a default zone which points to a zone managed by gnunet.org.
71 Use @code{gnunet-config -s gns} to view the GNS configuration, including
72 all configured zones that are operated by other users. The respective
73 configuration entry names start with a ``.'', i.e. ``.pin''.
75 You can configure any number of top-level domains, and point them to
76 the respective zones of your friends! For this, simply obtain the
77 respective public key (you will learn how below) and extend the
81 $ gnunet-config -s gns -n .myfriend -V PUBLIC_KEY
85 @subsection Managing Egos
87 In GNUnet, identity management is about managing egos. Egos can
88 correspond to pseudonyms or real-world identities. If you value your
89 privacy, you are encouraged to use separate egos for separate
92 Technically, an ego is first of all a public-private key pair, and
93 thus egos also always correspond to a GNS zone. Egos are managed by
94 the IDENTITY service. Note that this service has nothing to do with
95 the peer identity. The IDENTITY service essentially stores the
96 private keys under human-readable names, and keeps a mapping of which
97 private key should be used for particular important system functions.
98 The existing identities can be listed using the command
99 @command{gnunet-identity -d}
102 gnu - JTDVJC69NHU6GQS4B5721MV8VM7J6G2DVRGJV0ONIT6QH7OI6D50
103 rules - GO0T87F9BPMF8NKD5A54L2AH1T0GRML539TPFSRMCEA98182QD30
108 @subsection The GNS Tab
111 Maintaing your zones is through the NAMESTORE service and is discussed
112 here. You can manage your zone using @command{gnunet-identity} and
113 @command{gnunet-namestore}, or most conveniently using
114 @command{gnunet-namestore-gtk}.
116 We will use the GTK+ interface in this introduction. Please start
117 @command{gnunet-gkt} and switch to the GNS tab, which is the tab in
118 the middle with the letters "GNS" connected by a graph.
120 Next to the ``Add'' button there is a field where you can enter the
121 label (pseudonym in IDENTITY subsystem speak) of a zone you would like
122 to create. Pushing the ``Add'' button will create the zone.
123 Afterwards, you can change the label in the combo box below at any
124 time. The label will be the top-level domain that the GNU Name System
125 will resolve using your zone. For the label, you should pick
126 a name by which you would like to
127 be known by your friends (or colleagues). You should pick a label that
128 is reasonably unique within your social group. Be aware that
129 the label will be published together with every record in that zone.
131 Once you have created a first zone, you should see a QR code for the
132 zone on the right. Next to it is a "Copy" button to copy the public
133 key string to the clipboard. You can also save the QR code image to
136 Furthermore, you now can see the bottom part of the dialog. The
137 bottom of the window contains the existing entries in the selected zone.
139 @node Creating a Record
140 @subsection Creating a Record
143 We will begin by creating a simple record in your master zone.
144 To do this, click on the text "<new name>" in the table. The field is
145 editable, allowing you to enter a fresh label. Labels are restricted
146 to 63 characters and must not contain dots. For now, simply enter
147 "test", then press ENTER to confirm. This will create a new (empty)
148 record group under the label "test". Now click on "<new record>" next
149 to the new label "test". In the drop-down menu, select "A" and push
150 ENTER to confirm. Afterwards, a new dialog will pop up, asking to enter
151 details for the "A" record.
153 "A" records are used in the @dfn{Domain Name System} (DNS) to specify
154 IPv4 addresses. An IPv4 address is a number that is used to identify
155 and address a computer on the Internet (version 4). Please enter
156 "217.92.15.146" in the dialog below "Destination IPv4 Address" and
157 select "Record is public". Do not change any of the other options.
158 Note that as you enter a (well-formed) IPv4 address, the "Save"
159 button in the bottom right corner becomes sensitive. In general, buttons
160 in dialogs are often insensitive as long as the contents of the dialog
163 Once finished, press the "Save" button. Back in the main dialog, select
164 the tiny triangle left of the "test" label. By doing so, you get to see
165 all of the records under "test". Note that you can right-click a record
169 @node Resolving GNS records
170 @subsection Resolving GNS records
173 Next, you should try resolving your own GNS records. The method we
174 found to be the most uncomplicated is to do this by explicitly
175 resolving using @code{gnunet-gns}. For this exercise, we will assume
176 that you used the string ``gnu'' for the pseudonym (or label) of your
177 GNS zone. If you used something else, replace ``.gnu'' with your real
178 pseudonym in the examples below.
183 $ gnunet-gns -u test.gnu # what follows is the reply
185 Got `A' record: 217.92.15.146
189 That shows that resolution works, once GNS is integrated with
192 @node Integration with Browsers
193 @subsection Integration with Browsers
196 While we recommend integrating GNS using the NSS module in the
197 GNU libc Name Service Switch, you can also integrate GNS
198 directly with your browser via the @code{gnunet-gns-proxy}.
199 This method can have the advantage that the proxy can validate
200 TLS/X.509 records and thus strengthen web security; however, the proxy
201 is still a bit brittle, so expect subtle failures. We have had reasonable
202 success with Chromium, and various frustrations with Firefox in this area
205 The first step is to start the proxy. As the proxy is (usually)
206 not started by default, this is done as a unprivileged user
207 using @command{gnunet-arm -i gns-proxy}. Use @command{gnunet-arm -I}
208 as a unprivileged user to check that the proxy was actually
209 started. (The most common error for why the proxy may fail to start
210 is that you did not run @command{gnunet-gns-proxy-setup-ca} during
211 installation.) The proxy is a SOCKS5 proxy running (by default)
212 on port 7777. Thus, you need to now configure your browser to use
213 this proxy. With Chromium, you can do this by starting the browser
214 as a unprivileged user using
215 @command{chromium --proxy-server="socks5://localhost:7777"}
216 For @command{Firefox} (or @command{Icecat}), select "Edit-Preferences"
217 in the menu, and then select the "Advanced" tab in the dialog
220 Here, select "Settings..." to open the proxy settings dialog.
221 Select "Manual proxy configuration" and enter @code{localhost}
222 with port 7777 under SOCKS Host. Furthermore, set the
223 checkbox ``Proxy DNS when using SOCKS v5'' at the bottom of
224 the dialog. Finally, push "OK".
226 You must also go to about:config and change the
227 @code{browser.fixup.alternate.enabled} option to @code{false},
228 otherwise the browser will autoblunder an address like
229 @code{@uref{http://www.gnu/, www.gnu}} to
230 @code{@uref{http://www.gnu.com/, www.gnu.com}}. If you want
231 to resolve @@ in your own TLDs, you must additionally
232 set @code{browser.fixup.dns_first_use_for_single_words} to @code{true}.
234 After configuring your browser, you might want to first confirm that it
235 continues to work as before. (The proxy is still experimental and if you
236 experience "odd" failures with some webpages, you might want to disable
237 it again temporarily.) Next, test if things work by typing
238 "@uref{http://test.gnu/}" into the URL bar of your browser.
239 This currently fails with (my version of) Firefox as Firefox is
240 super-smart and tries to resolve "@uref{http://www.test.gnu/}" instead of
241 "@uref{test.gnu}". Chromium can be convinced to comply if you explicitly
242 include the "http://" prefix --- otherwise a Google search might be
243 attempted, which is not what you want. If successful, you should
244 see a simple website.
246 Note that while you can use GNS to access ordinary websites, this is
247 more an experimental feature and not really our primary goal at this
248 time. Still, it is a possible use-case and we welcome help with testing
252 @node Creating a Business Card
253 @subsection Creating a Business Card
254 @c FIXME: Which parts of texlive are needed? Some systems offer a modular
255 @c texlive (smaller size).
257 Before we can really use GNS, you should create a business card.
258 Note that this requires having @command{LaTeX} installed on your system.
259 If you are using a Debian GNU/Linux based operating system, the
260 following command should install the required components.
261 Keep in mind that this @b{requires 3GB} of downloaded data and possibly
262 @b{even more} when unpacked. On a GNU Guix based system texlive 2017 has
263 returns a DAG size of 5032.4 MiB.
264 @b{We welcome any help in identifying the required components of the
265 TexLive Distribution. This way we could just state the required components
266 without pulling in the full distribution of TexLive.}
269 apt-get install texlive-full
273 Start creating a business card by clicking the "Copy" button
274 in @command{gnunet-namestore-gtk}. Next, you should start
275 the @command{gnunet-bcd} program (in the terminal, on the command-line).
276 You do not need to pass any options, and please be not surprised if
280 $ gnunet-bcd # seems to hang...
284 Then, start a browser and point it to @uref{http://localhost:8888/}
285 where @code{gnunet-bcd} is running a Web server!
287 First, you might want to fill in the "GNS Public Key" field by
288 right-clicking and selecting "Paste", filling in the public key
289 from the copy you made in @command{gnunet-namestore-gtk}.
290 Then, fill in all of the other fields, including your @b{GNS NICKname}.
291 Adding a GPG fingerprint is optional.
292 Once finished, click "Submit Query".
293 If your @code{LaTeX} installation is incomplete, the result will be
295 Otherwise, you should get a PDF containing fancy 5x2 double-sided
296 translated business cards with a QR code containing your public key
298 We'll explain how to use those a bit later.
299 You can now go back to the shell running @code{gnunet-bcd} and press
300 @b{CTRL-C} to shut down the Web server.
304 @subsection Be Social
307 Next, you should print out your business card and be social.
308 Find a friend, help them install GNUnet and exchange business cards with
309 them. Or, if you're a desperate loner, you might try the next step with
310 your own card. Still, it'll be hard to have a conversation with
311 yourself later, so it would be better if you could find a friend.
312 You might also want a camera attached to your computer, so
313 you might need a trip to the store together.
315 Before we get started, we need to tell @code{gnunet-qr} which zone
316 it should import new records into. For this, run:
318 @pindex gnunet-identity
320 $ gnunet-identity -s namestore -e NAME
322 where NAME is the name of the zone you want to import records
323 into. In our running example, this would be ``gnu''.
326 Henceforth, for every business card you collect, simply run:
332 to open a window showing whatever your camera points at.
333 Hold up your friend's business card and tilt it until
334 the QR code is recognized. At that point, the window should
335 automatically close. At that point, your friend's NICKname and their
336 public key should have been automatically imported into your zone.
338 Assuming both of your peers are properly integrated in the
339 GNUnet network at this time, you should thus be able to
340 resolve your friends names. Suppose your friend's nickname
345 $ gnunet-gns -u test.bob.gnu
349 to check if your friend was as good at following instructions
353 @node Backup of Identities and Egos
354 @subsection Backup of Identities and Egos
357 One should always backup their files, especially in these SSD days (our
358 team has suffered 3 SSD crashes over a span of 2 weeks). Backing up peer
359 identity and zones is achieved by copying the following files:
361 The peer identity file can be found
362 in @file{~/.local/share/gnunet/private_key.ecc}
364 The private keys of your egos are stored in the
365 directory @file{~/.local/share/gnunet/identity/egos/}.
366 They are stored in files whose filenames correspond to the zones'
367 ego names. These are probably the most important files you want
368 to backup from a GNUnet installation.
370 Note: All these files contain cryptographic keys and they are
371 stored without any encryption. So it is advisable to backup
372 encrypted copies of them.
376 @subsection Revocation
378 Now, in the situation of an attacker gaining access to the private key of
379 one of your egos, the attacker can create records in the respective
381 and publish them as if you published them. Anyone resolving your
382 domain will get these new records and when they verify they seem
383 authentic because the attacker has signed them with your key.
385 To address this potential security issue, you can pre-compute
386 a revocation certificate corresponding to your ego. This certificate,
387 when published on the P2P network, flags your private key as invalid,
388 and all further resolutions or other checks involving the key will fail.
390 @pindex gnunet-revocation
391 A revocation certificate is thus a useful tool when things go out of
392 control, but at the same time it should be stored securely.
393 Generation of the revocation certificate for a zone can be done through
394 @command{gnunet-revocation}. For example, the following command (as
395 unprivileged user) generates a revocation file
396 @file{revocation.dat} for the zone @code{zone1}:
397 @command{gnunet-revocation -f revocation.dat -R zone1}
399 The above command only pre-computes a revocation certificate. It does
400 not revoke the given zone. Pre-computing a revocation certificate
401 involves computing a proof-of-work and hence may take up to 4 to 5 days
402 on a modern processor. Note that you can abort and resume the
403 calculation at any time. Also, even if you did not finish the
404 calculation, the resulting file will contain the signature, which is
405 sufficient to complete the revocation process even without access to
406 the private key. So instead of waiting for a few days, you can just
407 abort with CTRL-C, backup the revocation certificate and run the
408 calculation only if your key actually was compromised. This has the
409 disadvantage of revocation taking longer after the incident, but
410 the advantage of saving a significant amount of energy. So unless
411 you believe that a key compromise will need a rapid response, we
412 urge you to wait with generating the revocation certificate.
413 Also, the calculation is deliberately expensive, to deter people from
414 doing this just for fun (as the actual revocation operation is expensive
415 for the network, not for the peer performing the revocation).
418 @c FIXME: The Manual should give away the command using an example that is
419 @c very likely to never exist.
420 To avoid TL;DR ones from accidentally revocating their zones, we are not
421 giving away the command, but it is uncomplicated: the actual revocation is
422 performed by using the @command{-p} option of @command{gnunet-revocation}.
426 @subsection What's Next?
429 This may seem not like much of an application yet, but you have
430 just been one of the first to perform a decentralized secure name
431 lookup (where nobody could have altered the value supplied by your
432 friend) in a privacy-preserving manner (your query on the network
433 and the corresponding response were always encrypted). So what
434 can you really do with this? Well, to start with, you can publish your
435 GnuPG fingerprint in GNS as a "CERT" record and replace the public
436 web-of-trust with its complicated trust model with explicit names
437 and privacy-preserving resolution. Also, you should read the next
438 chapter of the tutorial and learn how to use GNS to have a
439 private conversation with your friend. Finally, help us
440 with the next GNUnet release for even more applications
441 using this new public key infrastructure.
443 @pindex gnunet-conservation-gtk
444 @node First steps - Using GNUnet Conversation
445 @section First steps - Using GNUnet Conversation
448 First, you should launch the graphical user interface. You can do
449 this from the command-line by typing
452 $ gnunet-conversation-gtk
456 * Testing your Audio Equipment::
460 @node Testing your Audio Equipment
461 @subsection Testing your Audio Equipment
464 First, you should use @code{gnunet-conversation-test} to check that your
465 microphone and speaker are working correctly. You will be prompted to
466 speak for 5 seconds, and then those 5 seconds will be replayed to you.
467 The network is not involved in this test. If it fails, you should run
468 your pulse audio configuration tool to check that microphone and
469 speaker are not muted and, if you have multiple input/output devices,
470 that the correct device is being associated with GNUnet's audio tools.
473 @subsection GNS Zones
476 @code{gnunet-conversation} uses GNS for addressing. This means that
477 you need to have a GNS zone created before using it. Information
478 about how to create GNS zones can be found here.
482 * Picking an Identity::
486 @node Picking an Identity
487 @subsubsection Picking an Identity
490 To make a call with @code{gnunet-conversation}, you first
491 need to choose an identity. This identity is both the caller ID
492 that will show up when you call somebody else, as well as the
493 GNS zone that will be used to resolve names of users that you
496 @pindex gnunet-conversation
498 gnunet-conversation -e zone-name
502 to start the command-line tool. You will see a message saying
503 that your phone is now "active on line 0". You can connect
504 multiple phones on different lines at the same peer. For the
505 first phone, the line zero is of course a fine choice.
507 Next, you should type in @command{/help} for a list of
508 available commands. We will explain the important ones
509 during this tutorial. First, you will need to type in
510 @command{/address} to determine the address of your
511 phone. The result should look something like this:
515 0-PD67SGHF3E0447TU9HADIVU9OM7V4QHTOG0EBU69TFRI2LG63DR0
519 Here, the "0" is your phone line, and what follows
520 after the hyphen is your peer's identity. This information will
521 need to be placed in a PHONE record of
522 your GNS master-zone so that other users can call you.
524 Start @code{gnunet-namestore-gtk} now (possibly from another
525 shell) and create an entry home-phone in your master zone.
526 For the record type, select PHONE. You should then see the
529 @image{images/gnunet-namestore-gtk-phone,5in,,Dialog to publish a PHONE record}
531 Note: Do not choose the expiry time to be 'Never'. If you
532 do that, you assert that this record will never change and
533 can be cached indefinitely by the DHT and the peers which
534 resolve this record. A reasonable period is 1 year.
536 Enter your peer identity under Peer and leave the line
537 at zero. Select the first option to make the record public.
538 If you entered your peer identity incorrectly,
539 the "Save" button will not work; you might want to use
540 copy-and-paste instead of typing in the peer identity
541 manually. Save the record.
543 @node Calling somebody
544 @subsubsection Calling somebody
547 Now you can call a buddy. Obviously, your buddy will have to have GNUnet
548 installed and must have performed the same steps. Also, you must have
549 your buddy in your GNS master zone, for example by having imported
550 your buddy's public key using @code{gnunet-qr}. Suppose your buddy
551 is in your zone as @code{buddy.mytld} and they also created their
552 phone using a label "home-phone". Then you can initiate a call using:
555 /call home-phone.buddy.mytld
558 It may take some time for GNUnet to resolve the name and to establish
559 a link. If your buddy has your public key in their master zone, they
560 should see an incoming call with your name. If your public key is not
561 in their master zone, they will just see the public key as the caller ID.
563 Your buddy then can answer the call using the "/accept" command. After
564 that, (encrypted) voice data should be relayed between your two peers.
565 Either of you can end the call using @command{/cancel}. You can exit
566 @code{gnunet-conversation} using @command{/quit}.
569 @node First steps - Using the GNUnet VPN
570 @section First steps - Using the GNUnet VPN
575 * VPN Preliminaries::
576 * GNUnet-Exit configuration::
577 * GNS configuration::
578 * Accessing the service::
582 @node VPN Preliminaries
583 @subsection VPN Preliminaries
586 To test the GNUnet VPN, we should first run a web server.
587 The easiest way to do this is to just start @code{gnunet-bcd},
588 which will run a webserver on port @code{8888} by default.
589 Naturally, you can run some other HTTP server for our little tutorial.
591 If you have not done this, you should also configure your
592 Name System Service switch to use GNS. In your @code{/etc/nsswitch.conf}
593 you should fine a line like this:
596 hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4
600 The exact details may differ a bit, which is fine. Add the text
601 @code{gns [NOTFOUND=return]} after @code{files}:
604 hosts: files gns [NOTFOUND=return] mdns4_minimal [NOTFOUND=return] dns mdns4
607 @c TODO: outdated section, we no longer install this as part of the
608 @c TODO: standard installation procedure and should point out the manual
609 @c TODO: steps required to make it useful.
611 You might want to make sure that @code{/lib/libnss_gns.so.2} exists on
612 your system, it should have been created during the installation.
616 $ configure --with-nssdir=/lib
617 $ cd src/gns/nss; sudo make install
621 to install the NSS plugins in the proper location.
623 @node GNUnet-Exit configuration
624 @subsection GNUnet-Exit configuration
627 Stop your peer (as user @code{gnunet}, run @command{gnunet-arm -e}) and
628 run @command{gnunet-setup}. In @command{gnunet-setup}, make sure to
629 activate the @strong{EXIT} and @strong{GNS} services in the General tab.
630 Then select the Exit tab. Most of the defaults should be fine (but
631 you should check against the screenshot that they have not been modified).
632 In the bottom area, enter @code{bcd} under Identifier and change the
633 Destination to @code{169.254.86.1:8888} (if your server runs on a port
634 other than 8888, change the 8888 port accordingly).
636 Now exit @command{gnunet-setup} and restart your peer
637 (@command{gnunet-arm -s}).
639 @node GNS configuration
640 @subsection GNS configuration
643 Now, using your normal user (not the @code{gnunet} system user), run
644 @command{gnunet-namestore-gtk}. Add a new label www in your
645 master zone. For the record type, select @code{VPN}. You should then
648 @image{images/gnunet-namestore-gtk-vpn,5in,,Dialog to publish a VPN record}
650 Under peer, you need to supply the peer identity of your own peer. You can
651 obtain the respective string by running @command{gnunet-peerinfo -sq}
652 as the @code{gnunet} user. For the Identifier, you need to supply the same
653 identifier that we used in the Exit setup earlier, so here supply "bcd".
654 If you want others to be able to use the service, you should probably make
655 the record public. For non-public services, you should use a passphrase
656 instead of the string "bcd". Save the record and
657 exit @command{gnunet-namestore-gtk}.
659 @node Accessing the service
660 @subsection Accessing the service
663 You should now be able to access your webserver. Type in:
666 $ wget http://www.gnu/
670 The request will resolve to the VPN record, telling the GNS resolver
671 to route it via the GNUnet VPN. The GNS resolver will ask the
672 GNUnet VPN for an IPv4 address to return to the application. The
673 VPN service will use the VPN information supplied by GNS to create
674 a tunnel (via GNUnet's MESH service) to the EXIT peer.
675 At the EXIT, the name "bcd" and destination port (80) will be mapped
676 to the specified destination IP and port. While all this is currently
677 happening on just the local machine, it should also work with other
678 peers --- naturally, they will need a way to access your GNS zone
679 first, for example by learning your public key from a QR code on
682 @node Using a Browser
683 @subsection Using a Browser
686 Sadly, modern browsers tend to bypass the Name Services Switch and
687 attempt DNS resolution directly. You can either run
688 a @code{gnunet-dns2gns} DNS proxy, or point the browsers to an
689 HTTP proxy. When we tried it, Iceweasel did not like to connect to
690 the socks proxy for @code{.gnu} TLDs, even if we disabled its
691 autoblunder of changing @code{.gnu} to ".gnu.com". Still,
692 using the HTTP proxy with Chrome does work.
695 @section File-sharing
698 This chapter documents the GNUnet file-sharing application. The original
699 file-sharing implementation for GNUnet was designed to provide
700 @strong{anonymous} file-sharing. However, over time, we have also added
701 support for non-anonymous file-sharing (which can provide better
702 performance). Anonymous and non-anonymous file-sharing are quite
703 integrated in GNUnet and, except for routing, share most of the concepts
704 and implementation. There are three primary file-sharing operations:
705 publishing, searching and downloading. For each of these operations,
706 the user specifies an @strong{anonymity level}. If both the publisher and
707 the searcher/downloader specify "no anonymity", non-anonymous
708 file-sharing is used. If either user specifies some desired degree
709 of anonymity, anonymous file-sharing will be used.
711 After a short introduction, we will first look at the various concepts
712 in GNUnet's file-sharing implementation. Then, we will discuss
713 specifics as to how they impact users that publish, search or download
722 * Namespace Management::
723 * File-Sharing URIs::
724 * GTK User Interface::
728 @subsection Searching
731 The command @command{gnunet-search} can be used to search
732 for content on GNUnet. The format is:
735 $ gnunet-search [-t TIMEOUT] KEYWORD
739 The @command{-t} option specifies that the query should timeout after
740 approximately TIMEOUT seconds. A value of zero (``0'') is interpreted
741 as @emph{no timeout}, which is the default. In this case,
742 @command{gnunet-search} will never terminate (unless you press
745 If multiple words are passed as keywords, they will all be
746 considered optional. Prefix keywords with a "+" to make them mandatory.
748 Note that searching using
751 $ gnunet-search Das Kapital
755 is not the same as searching for
758 $ gnunet-search "Das Kapital"
762 as the first will match files shared under the keywords
763 "Das" or "Kapital" whereas the second will match files
764 shared under the keyword "Das Kapital".
766 Search results are printed by @command{gnunet-search} like this:
768 @c it will be better the avoid the ellipsis altogether because I don't
769 @c understand the explanation below that
770 @c ng0: who is ``I'' and what was the complete sentence?
773 gnunet-download -o "COPYING" gnunet://fs/chk/PGK8M...3EK130.75446
778 The whole line is the command you would have to enter to download
779 the file. The first argument passed to @code{-o} is the suggested
780 filename (you may change it to whatever you like).
781 It is followed by the key for decrypting the file, the query for
782 searching the file, a checksum (in hexadecimal) finally the size of
786 @subsection Downloading
789 In order to download a file, you need the whole line returned by
790 @command{gnunet-search}.
791 You can then use the tool @command{gnunet-download} to obtain the file:
794 $ gnunet-download -o <FILENAME> <GNUNET-URL>
798 FILENAME specifies the name of the file where GNUnet is supposed
799 to write the result. Existing files are overwritten. If the
800 existing file contains blocks that are identical to the
801 desired download, those blocks will not be downloaded again
804 If you want to download the GPL from the previous example,
805 you do the following:
808 $ gnunet-download -o "COPYING" gnunet://fs/chk/PGK8M...3EK130.75446
812 If you ever have to abort a download, you can continue it at any time by
813 re-issuing @command{gnunet-download} with the same filename.
814 In that case, GNUnet will @strong{not} download blocks again that are
817 GNUnet's file-encoding mechanism will ensure file integrity, even if the
818 existing file was not downloaded from GNUnet in the first place.
820 You may want to use the @command{-V} switch to turn on verbose
821 reporting. In this case, @command{gnunet-download} will print the
822 current number of bytes downloaded whenever new data was received.
825 @subsection Publishing
828 The command @command{gnunet-publish} can be used to add content
829 to the network. The basic format of the command is
832 $ gnunet-publish [-n] [-k KEYWORDS]* [-m TYPE:VALUE] FILENAME
837 $ gnunet-publish -m "description:GNU License" -k gpl -k test -m "mimetype:text/plain" COPYING
841 * Important command-line options::
842 * Indexing vs. Inserting::
845 @node Important command-line options
846 @subsubsection Important command-line options
849 The option @code{-k} is used to specify keywords for the file that
850 should be inserted. You can supply any number of keywords,
851 and each of the keywords will be sufficient to locate and
852 retrieve the file. Please note that you must use the @code{-k} option
853 more than once -- one for each expression you use as a keyword for
856 The -m option is used to specify meta-data, such as descriptions.
857 You can use -m multiple times. The TYPE passed must be from the
858 list of meta-data types known to libextractor. You can obtain this
859 list by running @command{extract -L}. Use quotes around the entire
860 meta-data argument if the value contains spaces. The meta-data
861 is displayed to other users when they select which files to
862 download. The meta-data and the keywords are optional and
863 may be inferred using @code{GNU libextractor}.
865 @command{gnunet-publish} has a few additional options to handle
866 namespaces and directories. Refer to the man-page for details:
872 @node Indexing vs. Inserting
873 @subsubsection Indexing vs Inserting
876 By default, GNUnet indexes a file instead of making a full copy.
877 This is much more efficient, but requires the file to stay unaltered
878 at the location where it was when it was indexed. If you intend to move,
879 delete or alter a file, consider using the option @code{-n} which will
880 force GNUnet to make a copy of the file in the database.
882 Since it is much less efficient, this is strongly discouraged for large
883 files. When GNUnet indexes a file (default), GNUnet does @strong{not}
884 create an additional encrypted copy of the file but just computes a
885 summary (or index) of the file. That summary is approximately two percent
886 of the size of the original file and is stored in GNUnet's database.
887 Whenever a request for a part of an indexed file reaches GNUnet,
888 this part is encrypted on-demand and send out. This way, there is no
889 need for an additional encrypted copy of the file to stay anywhere
890 on the drive. This is different from other systems, such as Freenet,
891 where each file that is put online must be in Freenet's database in
892 encrypted format, doubling the space requirements if the user wants
893 to preserve a directly accessible copy in plaintext.
895 Thus indexing should be used for all files where the user will keep
896 using this file (at the location given to gnunet-publish) and does
897 not want to retrieve it back from GNUnet each time. If you want to
898 remove a file that you have indexed from the local peer, use the tool
899 @command{gnunet-unindex} to un-index the file.
901 The option @code{-n} may be used if the user fears that the file might
902 be found on their drive (assuming the computer comes under the control
903 of an adversary). When used with the @code{-n} flag, the user has a
904 much better chance of denying knowledge of the existence of the file,
905 even if it is still (encrypted) on the drive and the adversary is
906 able to crack the encryption (e.g. by guessing the keyword.
912 For better results with filesharing it is useful to understand the
914 In addition to anonymous routing GNUnet attempts to give users a better
915 experience in searching for content. GNUnet uses cryptography to safely
916 break content into smaller pieces that can be obtained from different
917 sources without allowing participants to corrupt files. GNUnet makes it
918 difficult for an adversary to send back bogus search results. GNUnet
919 enables content providers to group related content and to establish a
920 reputation. Furthermore, GNUnet allows updates to certain content to be
921 made available. This section is supposed to introduce users to the
922 concepts that are used to achieve these goals.
941 A file in GNUnet is just a sequence of bytes. Any file-format is allowed
942 and the maximum file size is theoretically @math{2^64 - 1} bytes, except
943 that it would take an impractical amount of time to share such a file.
944 GNUnet itself never interprets the contents of shared files, except when
945 using GNU libextractor to obtain keywords.
948 @subsubsection Keywords
951 Keywords are the most simple mechanism to find files on GNUnet.
952 Keywords are @strong{case-sensitive} and the search string
953 must always match @strong{exactly} the keyword used by the
954 person providing the file. Keywords are never transmitted in
955 plaintext. The only way for an adversary to determine the keyword
956 that you used to search is to guess it (which then allows the
957 adversary to produce the same search request). Since providing
958 keywords by hand for each shared file is tedious, GNUnet uses
959 GNU libextractor to help automate this process. Starting a
960 keyword search on a slow machine can take a little while since
961 the keyword search involves computing a fresh RSA key to formulate the
965 @subsubsection Directories
968 A directory in GNUnet is a list of file identifiers with meta data.
969 The file identifiers provide sufficient information about the files
970 to allow downloading the contents. Once a directory has been created,
971 it cannot be changed since it is treated just like an ordinary file
972 by the network. Small files (of a few kilobytes) can be inlined in
973 the directory, so that a separate download becomes unnecessary.
975 Directories are shared just like ordinary files. If you download a
976 directory with @command{gnunet-download}, you can use
977 @command{gnunet-directory} to list its contents. The canonical
978 extension for GNUnet directories when stored as files in your
979 local file-system is ".gnd". The contents of a directory are URIs and
981 The URIs contain all the information required by
982 @command{gnunet-download} to retrieve the file. The meta data
983 typically includes the mime-type, description, a filename and
984 other meta information, and possibly even the full original file
990 When sharing files, it is sometimes desirable to build a reputation as
991 a source for quality information. With egos, publishers can
992 (cryptographically) sign files, thereby demonstrating that various
993 files were published by the same entity. An ego thus allows users to
994 link different publication events, thereby deliberately reducing
995 anonymity to pseudonymity.
997 Egos used in GNUnet's file-sharing for such pseudonymous publishing
998 also correspond to the egos used to identify and sign zones in the
999 GNU Name System. However, if the same ego is used for file-sharing
1000 and for a GNS zone, this will weaken the privacy assurances provided
1001 by the anonymous file-sharing protocol.
1003 Note that an ego is NOT bound to a GNUnet peer. There can be multiple
1004 egos for a single user, and users could (theoretically) share
1005 the private keys of an ego by copying the respective private keys.
1009 @subsubsection Namespaces
1011 A namespace is a set of files that were signed by the same ego.
1012 Today, namespaces are implemented independently of GNS zones, but
1013 in the future we plan to merge the two such that a GNS zone can
1014 basically contain files using a file-sharing specific record type.
1016 Files (or directories) that have been signed and placed into a
1017 namespace can be updated. Updates are identified as authentic if the
1018 same secret key was used to sign the update.
1020 @node Advertisements
1021 @subsubsection Advertisements
1023 Advertisements are used to notify other users about the existence of a
1024 namespace. Advertisements are propagated using the normal keyword
1025 search. When an advertisement is received (in response to a search),
1026 the namespace is added to the list of namespaces available in the
1027 namespace-search dialogs of gnunet-fs-gtk and printed by
1028 @code{gnunet-identity}. Whenever a namespace is created, an
1029 appropriate advertisement can be generated. The default keyword for
1030 the advertising of namespaces is "namespace".
1033 @node Anonymity level
1034 @subsubsection Anonymity level
1036 The anonymity level determines how hard it should be for an adversary to
1037 determine the identity of the publisher or the searcher/downloader. An
1038 anonymity level of zero means that anonymity is not required. The default
1039 anonymity level of "1" means that anonymous routing is desired, but no
1040 particular amount of cover traffic is necessary. A powerful adversary
1041 might thus still be able to deduce the origin of the traffic using
1042 traffic analysis. Specifying higher anonymity levels increases the
1043 amount of cover traffic required.
1045 The specific numeric value (for anonymity levels above 1) is simple:
1046 Given an anonymity level L (above 1), each request FS makes on your
1047 behalf must be hidden in L-1 equivalent requests of cover traffic
1048 (traffic your peer routes for others) in the same time-period. The
1049 time-period is twice the average delay by which GNUnet artificially
1052 While higher anonymity levels may offer better privacy, they can also
1053 significantly hurt performance.
1056 @node Content Priority
1057 @subsubsection Content Priority
1059 Depending on the peer's configuration, GNUnet peers migrate content
1060 between peers. Content in this sense are individual blocks of a file,
1061 not necessarily entire files. When peers run out of space (due to
1062 local publishing operations or due to migration of content from other
1063 peers), blocks sometimes need to be discarded. GNUnet first always
1064 discards expired blocks (typically, blocks are published with an
1065 expiration of about two years in the future; this is another option).
1066 If there is still not enough space, GNUnet discards the blocks with the
1067 lowest priority. The priority of a block is decided by its popularity
1068 (in terms of requests from peers we trust) and, in case of blocks
1069 published locally, the base-priority that was specified by the user
1070 when the block was published initially.
1074 @subsubsection Replication
1076 When peers migrate content to other systems, the replication level
1077 of a block is used to decide which blocks need to be migrated most
1078 urgently. GNUnet will always push the block with the highest
1079 replication level into the network, and then decrement the replication
1080 level by one. If all blocks reach replication level zero, the
1081 selection is simply random.
1084 @node Namespace Management
1085 @subsection Namespace Management
1087 The @code{gnunet-identity} tool can be used to create egos.
1088 By default, @code{gnunet-identity -D} simply
1089 lists all locally available egos.
1098 @subsubsection Creating Egos
1100 With the @command{-C NICK} option it can also be used to create a new
1101 ego. An ego is the virtual identity of the entity in control of a
1102 namespace or GNS zone. Anyone can create any number of egos. The
1103 provided NICK name automatically corresponds to a GNU Name System
1104 domain name. Thus, henceforth name resolution for any name ending in
1105 ``.NICK'' will use the NICK's zone. You should avoid using NICKs that
1106 collide with well-known DNS names.
1109 @subsubsection Deleting Egos
1111 With the @command{-D NICK} option egos can be deleted. Once the ego
1112 has been deleted it is impossible to add content to the corresponding
1113 namespace or zone. However, the existing GNS zone data is currently
1114 not dropped. This may change in the future.
1116 Deleting the pseudonym does not make the namespace or any content in
1119 @node File-Sharing URIs
1120 @subsection File-Sharing URIs
1123 GNUnet (currently) uses four different types of URIs for
1124 file-sharing. They all begin with "gnunet://fs/".
1125 This section describes the four different URI types in detail.
1127 For FS URIs empty KEYWORDs are not allowed. Quotes are allowed to
1128 denote whitespace between words. Keywords must contain a balanced
1129 number of double quotes. Doubles quotes can not be used in the actual
1130 keywords. This means that the the string '""foo bar""' will be turned
1131 into two OR-ed keywords 'foo' and 'bar', not into '"foo bar"'.
1134 * Encoding of hash values in URIs::
1135 * Content Hash Key (chk)::
1136 * Location identifiers (loc)::
1137 * Keyword queries (ksk)::
1138 * Namespace content (sks)::
1141 @node Encoding of hash values in URIs
1142 @subsubsection Encoding of hash values in URIs
1145 Most URIs include some hash values. Hashes are encoded using
1146 base32hex (RFC 2938).
1149 @node Content Hash Key (chk)
1150 @subsubsection Content Hash Key (chk)
1153 A chk-URI is used to (uniquely) identify a file or directory
1154 and to allow peers to download the file. Files are stored in
1155 GNUnet as a tree of encrypted blocks.
1156 The chk-URI thus contains the information to download and decrypt
1157 those blocks. A chk-URI has the format
1158 "gnunet://fs/chk/KEYHASH.QUERYHASH.SIZE". Here, "SIZE"
1159 is the size of the file (which allows a peer to determine the
1160 shape of the tree), KEYHASH is the key used to decrypt the file
1161 (also the hash of the plaintext of the top block) and QUERYHASH
1162 is the query used to request the top-level block (also the hash
1163 of the encrypted block).
1166 @node Location identifiers (loc)
1167 @subsubsection Location identifiers (loc)
1170 For non-anonymous file-sharing, loc-URIs are used to specify which
1171 peer is offering the data (in addition to specifying all of the
1172 data from a chk-URI). Location identifiers include a digital
1173 signature of the peer to affirm that the peer is truly the
1174 origin of the data. The format is
1175 "gnunet://fs/loc/KEYHASH.QUERYHASH.SIZE.PEER.SIG.EXPTIME".
1176 Here, "PEER" is the public key of the peer (in GNUnet format in
1177 base32hex), SIG is the RSA signature (in GNUnet format in
1178 base32hex) and EXPTIME specifies when the signature expires
1179 (in milliseconds after 1970).
1182 @node Keyword queries (ksk)
1183 @subsubsection Keyword queries (ksk)
1186 A keyword-URI is used to specify that the desired operation
1187 is the search using a particular keyword. The format is simply
1188 "gnunet://fs/ksk/KEYWORD". Non-ASCII characters can be specified
1189 using the typical URI-encoding (using hex values) from HTTP.
1190 "+" can be used to specify multiple keywords (which are then
1191 logically "OR"-ed in the search, results matching both keywords
1192 are given a higher rank): "gnunet://fs/ksk/KEYWORD1+KEYWORD2".
1193 ksk-URIs must not begin or end with the plus ('+') character.
1194 Furthermore they must not contain '++'.
1197 @node Namespace content (sks)
1198 @subsubsection Namespace content (sks)
1201 @b{Please note that the text in this subsection is outdated and needs}
1202 @b{to be rewritten for version 0.10!}
1203 @b{This especially concerns the terminology of Pseudonym/Ego/Identity.}
1205 Namespaces are sets of files that have been approved by some (usually
1206 pseudonymous) user --- typically by that user publishing all of the
1207 files together. A file can be in many namespaces. A file is in a
1208 namespace if the owner of the ego (aka the namespace's private key)
1209 signs the CHK of the file cryptographically. An SKS-URI is used to
1210 search a namespace. The result is a block containing meta data,
1211 the CHK and the namespace owner's signature. The format of a sks-URI
1212 is "gnunet://fs/sks/NAMESPACE/IDENTIFIER". Here, "NAMESPACE"
1213 is the public key for the namespace. "IDENTIFIER" is a freely
1214 chosen keyword (or password!). A commonly used identifier is
1215 "root" which by convention refers to some kind of index or other
1216 entry point into the namespace.
1218 @node GTK User Interface
1219 @subsection GTK User Interface
1220 This chapter describes first steps for file-sharing with GNUnet.
1221 To start, you should launch @command{gnunet-fs-gtk}.
1223 As we want to be sure that the network contains the data that we are
1224 looking for for testing, we need to begin by publishing a file.
1232 @node gtk-Publishing
1233 @subsubsection Publishing
1236 To publish a file, select "File Sharing" in the menu bar just below the
1237 "Statistics" icon, and then select "Publish" from the menu.
1239 Afterwards, the following publishing dialog will appear:
1241 @image{images/gnunet-gtk-0-10-fs-publish,5in,,The gnunet-fs-gtk publishing dialog}
1243 In this dialog, select the "Add File" button. This will open a
1244 file selection dialog:
1246 @image{images/gnunet-gtk-0-10-fs-publish-select,5in,,Dialog to select the file to publish (looks may differ for other Gtk+ versions)}
1248 Now, you should select a file from your computer to be published on
1249 GNUnet. To see more of GNUnet's features later, you should pick a
1250 PNG or JPEG file this time. You can leave all of the other options
1251 in the dialog unchanged. Confirm your selection by pressing the "OK"
1252 button in the bottom right corner. Now, you will briefly see a
1253 "Messages..." dialog pop up, but most likely it will be too short for
1254 you to really read anything. That dialog is showing you progress
1255 information as GNUnet takes a first look at the selected file(s).
1256 For a normal image, this is virtually instant, but if you later
1257 import a larger directory you might be interested in the progress dialog
1258 and potential errors that might be encountered during processing.
1259 After the progress dialog automatically disappears, your file
1260 should now appear in the publishing dialog:
1262 @image{images/gnunet-gtk-0-10-fs-publish-with-file,5in,,Publishing dialog with file added}
1264 Now, select the file (by clicking on the file name) and then click
1265 the "Edit" button. This will open the editing dialog:
1267 @image{images/gnunet-gtk-0-10-fs-publish-editing,5in,,Editing meta data of a file to be published}
1269 In this dialog, you can see many details about your file. In the
1270 top left area, you can see meta data extracted about the file,
1271 such as the original filename, the mimetype and the size of the image.
1272 In the top right, you should see a preview for the image
1273 (if GNU libextractor was installed correctly with the
1274 respective plugins). Note that if you do not see a preview, this
1275 is not a disaster, but you might still want to install more of
1276 GNU libextractor in the future. In the bottom left, the dialog contains
1277 a list of keywords. These are the keywords under which the file will be
1278 made available. The initial list will be based on the extracted meta data.
1279 Additional publishing options are in the right bottom corner. We will
1280 now add an additional keyword to the list of keywords. This is done by
1281 entering the keyword above the keyword list between the label "Keyword"
1282 and the "Add keyword" button. Enter "test" and select "Add keyword".
1283 Note that the keyword will appear at the bottom of the existing keyword
1284 list, so you might have to scroll down to see it. Afterwards, push the
1285 "OK" button at the bottom right of the dialog.
1287 You should now be back at the "Publish content on GNUnet" dialog. Select
1288 "Execute" in the bottom right to close the dialog and publish your file
1289 on GNUnet! Afterwards, you should see the main dialog with a new area
1290 showing the list of published files (or ongoing publishing operations
1291 with progress indicators).
1294 @subsubsection Searching
1297 Below the menu bar, there are four entry widges labeled "Namespace",
1298 "Keywords", "Anonymity" and "Mime-type" (from left to right). These
1299 widgets are used to control searching for files in GNUnet. Between the
1300 "Keywords" and "Anonymity" widgets, there is also a big "Search" button,
1301 which is used to initiate the search. We will ignore the "Namespace",
1302 "Anonymity" and "Mime-type" options in this tutorial, please leave them
1303 empty. Instead, simply enter "test" under "Keywords" and press "Search".
1304 Afterwards, you should immediately see a new tab labeled after your
1305 search term, followed by the (current) number of search
1306 results --- "(15)" in our screenshot. Note that your results may
1307 vary depending on what other users may have shared and how your
1310 You can now select one of the search results. Once you do this,
1311 additional information about the result should be displayed on the
1312 right. If available, a preview image should appear on the top right.
1313 Meta data describing the file will be listed at the bottom right.
1315 Once a file is selected, at the bottom of the search result list
1316 a little area for downloading appears.
1318 @node gtk-Downloading
1319 @subsubsection Downloading
1322 In the downloading area, you can select the target directory (default is
1323 "Downloads") and specify the desired filename (by default the filename it
1324 taken from the meta data of the published file). Additionally, you can
1325 specify if the download should be anonymous and (for directories) if
1326 the download should be recursive. In most cases, you can simply start
1327 the download with the "Download!" button.
1329 Once you selected download, the progress of the download will be
1330 displayed with the search result. You may need to resize the result
1331 list or scroll to the right. The "Status" column shows the current
1332 status of the download, and "Progress" how much has been completed.
1333 When you close the search tab (by clicking on the "X" button next to
1334 the "test" label), ongoing and completed downloads are not aborted
1335 but moved to a special "*" tab.
1337 You can remove completed downloads from the "*" tab by clicking the
1338 cleanup button next to the "*". You can also abort downloads by right
1339 clicking on the respective download and selecting "Abort download"
1342 That's it, you now know the basics for file-sharing with GNUnet!
1345 @node The GNU Name System
1346 @section The GNU Name System
1350 The GNU Name System (GNS) is secure and decentralized naming system.
1351 It allows its users to resolve and register names within the @code{.gnu}
1352 @dfn{top-level domain} (TLD).
1354 GNS is designed to provide:
1356 @item Censorship resistance
1358 @item Secure name resolution
1359 @item Compatibility with DNS
1362 For the initial configuration and population of your
1363 GNS installation, please follow the GNS setup instructions.
1364 The remainder of this chapter will provide some background on GNS
1365 and then describe how to use GNS in more detail.
1367 Unlike DNS, GNS does not rely on central root zones or authorities.
1368 Instead any user administers their own root and can can create arbitrary
1369 name value mappings. Furthermore users can delegate resolution to other
1370 users' zones just like DNS NS records do. Zones are uniquely identified
1371 via public keys and resource records are signed using the corresponding
1372 public key. Delegation to another user's zone is done using special PKEY
1373 records and petnames. A petname is a name that can be freely chosen by
1374 the user. This results in non-unique name-value mappings as
1375 @code{@uref{http://www.bob.gnu/, www.bob.gnu}} to one user might be
1376 @code{@uref{http://www.friend.gnu/, www.friend.gnu}} for someone else.
1381 * Maintaining your own Zones::
1382 * Obtaining your Zone Key::
1383 * Adding Links to Other Zones::
1384 * Using Public Keys as Top Level Domains::
1385 * Resource Records in GNS::
1386 * Synchronizing with legacy DNS::
1387 * Migrating an existing DNS zone into GNS::
1391 @node Creating a Zone
1392 @subsection Creating a Zone
1394 To use GNS, you probably should create at least one zone of your own.
1395 You can create any number of zones using the gnunet-identity tool
1399 $ gnunet-identity -C "myzone"
1402 Henceforth, on your system you control the TLD ``myzone''.
1404 All of your zones can be listed (displayed) using the
1405 @command{gnunet-identity} command line tool as well:
1408 $ gnunet-identity -d
1411 @node Maintaining your own Zones
1412 @subsection Maintaining your own Zones
1415 Now you can add (or edit, or remove) records in your GNS zone using the
1416 @command{gnunet-namestore-gtk} GUI or using the @command{gnunet-namestore}
1418 In either case, your records will be stored in an SQL database under
1419 control of the @command{gnunet-service-namestore}.
1420 Note that if multiple users use one peer, the namestore database will
1421 include the combined records of all users.
1422 However, users will not be able to see each other's records
1423 if they are marked as private.
1425 To provide a short example for editing your own zone, suppose you
1426 have your own web server with the IP @code{1.2.3.4}. Then you can put an
1427 @code{A} record (@code{A} records in DNS are for IPv4 IP addresses)
1428 into your local zone ``myzone'' using the command:
1431 $ gnunet-namestore -z myzone -a -n www -t A -V 1.2.3.4 -e never
1435 Afterwards, you will be able to access your webpage under "www.myzone"
1436 (assuming your webserver does not use virtual hosting, if it does,
1437 please read up on setting up the GNS proxy).
1439 Similar commands will work for other types of DNS and GNS records,
1440 the syntax largely depending on the type of the record.
1441 Naturally, most users may find editing the zones using the
1442 @command{gnunet-namestore-gtk} GUI to be easier.
1444 @node Obtaining your Zone Key
1445 @subsection Obtaining your Zone Key
1447 Each zone in GNS has a public-private key. Usually, gnunet-namestore and
1448 gnunet-setup will access your private key as necessary, so you do not
1449 have to worry about those. What is important is your public key
1450 (or rather, the hash of your public key), as you will likely want to
1451 give it to others so that they can securely link to you.
1453 You can usually get the hash of your public key using
1456 $ gnunet-identity -d $options | grep myzone | awk '@{print $3@}'
1460 For example, the output might be something like:
1463 DC3SEECJORPHQNVRH965A6N74B1M37S721IG4RBQ15PJLLPJKUE0
1467 Alternatively, you can obtain a QR code with your zone key AND your
1468 pseudonym from gnunet-namestore-gtk. The QR code is displayed in the
1469 main window and can be stored to disk using the ``Save as'' button
1472 @node Adding Links to Other Zones
1473 @subsection Adding Links to Other Zones
1476 A central operation in GNS is the ability to securely delegate to
1477 other zones. Basically, by adding a delegation you make all of the
1478 names from the other zone available to yourself. This section
1479 describes how to create delegations.
1481 Suppose you have a friend who you call 'bob' who also uses GNS.
1482 You can then delegate resolution of names to Bob's zone by adding
1483 a PKEY record to their local zone:
1486 $ gnunet-namestore -a -n bob --type PKEY -V XXXX -e never -Z myzone
1490 Note that ``XXXX'' in the command above must be replaced with the hash
1491 of Bob's public key (the output your friend obtained using the
1492 @command{gnunet-identity} command from the previous section and told
1493 you, for example by giving you a business card containing this
1494 information as a QR code).
1496 Assuming Bob has an ``A'' record for their website under the name of
1497 ``www'' in his zone, you can then access Bob's website under
1498 ``www.bob.myzone'' --- as well as any (public) GNS record that Bob has
1499 in their zone by replacing www with the respective name of the
1500 record in Bob's zone.
1502 @c themselves? themself?
1503 Furthermore, if Bob has themselves a (public) delegation to Carol's
1504 zone under "carol", you can access Carol's records under
1505 ``NAME.carol.bob.myzone'' (where ``NAME'' is the name of Carol's
1506 record you want to access).
1509 @node Using Public Keys as Top Level Domains
1510 @subsection Using Public Keys as Top Level Domains
1513 GNS also assumes responsibility for any name that uses in a
1514 well-formed public key for the TLD. Names ending this way are then
1515 resolved by querying the respective zone. Such public key TLDs are
1516 expected to be used under rare circumstances where globally unique
1517 names are required, and for integration with legacy systems.
1519 @node Resource Records in GNS
1520 @subsection Resource Records in GNS
1523 GNS supports the majority of the DNS records as defined in
1524 @uref{http://www.ietf.org/rfc/rfc1035.txt, RFC 1035}. Additionally,
1525 GNS defines some new record types the are unique to the GNS system.
1526 For example, GNS-specific resource records are used to give petnames
1527 for zone delegation, revoke zone keys and provide some compatibility
1530 For some DNS records, GNS does extended processing to increase their
1531 usefulness in GNS. In particular, GNS introduces special names
1532 referred to as "zone relative names". Zone relative names are allowed
1533 in some resource record types (for example, in NS and CNAME records)
1534 and can also be used in links on webpages. Zone relative names end
1535 in ".+" which indicates that the name needs to be resolved relative
1536 to the current authoritative zone. The extended processing of those
1537 names will expand the ".+" with the correct delegation chain to the
1538 authoritative zone (replacing ".+" with the name of the location
1539 where the name was encountered) and hence generate a
1542 GNS currently supports the following record types:
1553 * SOA SRV PTR and MX::
1558 * ID TOKEN METADATA::
1564 * RECLAIM OIDC CLIENT::
1565 * RECLAIM OIDC REDIRECT::
1571 A NICK record is used to give a zone a name. With a NICK record, you
1572 can essentially specify how you would like to be called. GNS expects
1573 this record under the empty label ``@@'' in the zone's database
1574 (NAMESTORE); however, it will then automatically be copied into each
1575 record set, so that clients never need to do a separate lookup to
1576 discover the NICK record. Also, users do not usually have to worry
1577 about setting the NICK record: it is automatically set to the local
1583 Name: @@; RRType: NICK; Value: bob
1587 This record in Bob's zone will tell other users that this zone wants
1588 to be referred to as 'bob'. Note that nobody is obliged to call Bob's
1589 zone 'bob' in their own zones. It can be seen as a
1590 recommendation ("Please call this zone 'bob'").
1595 PKEY records are used to add delegation to other users' zones and
1596 give those zones a petname.
1600 Let Bob's zone be identified by the hash "ABC012". Bob is your friend
1601 so you want to give them the petname "friend". Then you add the
1602 following record to your zone:
1605 Name: friend; RRType: PKEY; Value: ABC012;
1609 This will allow you to resolve records in bob's zone
1610 under "*.friend.gnu".
1615 BOX records are there to integrate information from TLSA or
1616 SRV records under the main label. In DNS, TLSA and SRV records
1617 use special names of the form @code{_port._proto.(label.)*tld} to
1618 indicate the port number and protocol (i.e. tcp or udp) for which
1619 the TLSA or SRV record is valid. This causes various problems, and
1620 is elegantly solved in GNS by integrating the protocol and port
1621 numbers together with the respective value into a "BOX" record.
1622 Note that in the GUI, you do not get to edit BOX records directly
1623 right now --- the GUI will provide the illusion of directly
1624 editing the TLSA and SRV records, even though they internally
1630 The LEgacy HOstname of a server. Some webservers expect a specific
1631 hostname to provide a service (virtiual hosting). Also SSL
1632 certificates usually contain DNS names. To provide the expected
1633 legacy DNS name for a server, the LEHO record can be used.
1634 To mitigate the just mentioned issues the GNS proxy has to be used.
1635 The GNS proxy will use the LEHO information to apply the necessary
1641 GNS allows easy access to services provided by the GNUnet Virtual Public
1642 Network. When the GNS resolver encounters a VPN record it will contact
1643 the VPN service to try and allocate an IPv4/v6 address (if the queries
1644 record type is an IP address) that can be used to contact the service.
1648 I want to provide access to the VPN service "web.gnu." on port 80 on peer
1650 Name: www; RRType: VPN; Value: 80 ABC012 web.gnu.
1652 The peer ABC012 is configured to provide an exit point for the service
1653 "web.gnu." on port 80 to it's server running locally on port 8080 by
1654 having the following lines in the @file{gnunet.conf} configuration file:
1658 TCP_REDIRECTS = 80:localhost4:8080
1661 @node A AAAA and TXT
1662 @subsubsection A AAAA and TXT
1664 Those records work in exactly the same fashion as in traditional DNS.
1667 @subsubsection CNAME
1669 As specified in RFC 1035 whenever a CNAME is encountered the query
1670 needs to be restarted with the specified name. In GNS a CNAME
1674 @item A zone relative name,
1675 @item A zkey name or
1676 @item A DNS name (in which case resolution will continue outside
1677 of GNS with the systems DNS resolver)
1681 @subsubsection GNS2DNS
1683 GNS can delegate authority to a legacy DNS zone. For this, the
1684 name of the DNS nameserver and the name of the DNS zone are
1685 specified in a GNS2DNS record.
1690 Name: pet; RRType: GNS2DNS; Value: gnunet.org@@a.ns.joker.com
1694 Any query to @code{pet.gnu} will then be delegated to the DNS server at
1695 @code{a.ns.joker.com}. For example,
1696 @code{@uref{http://www.pet.gnu/, www.pet.gnu}} will result in a DNS query
1697 for @code{@uref{http://www.gnunet.org/, www.gnunet.org}} to the server
1698 at @code{a.ns.joker.com}. Delegation to DNS via NS records in GNS can
1699 be useful if you do not want to start resolution in the DNS root zone
1700 (due to issues such as censorship or availability).
1702 Note that you would typically want to use a relative name for the
1706 Name: pet; RRType: GNS2DNS; Value: gnunet.org@@ns-joker.+@
1707 Name: ns-joker; RRType: A; Value: 184.172.157.218
1711 This way, you can avoid involving the DNS hierarchy in the resolution of
1712 @code{a.ns.joker.com}. In the example above, the problem may not be
1713 obvious as the nameserver for "gnunet.org" is in the ".com" zone.
1714 However, imagine the nameserver was "ns.gnunet.org". In this case,
1715 delegating to "ns.gnunet.org" would mean that despite using GNS,
1716 censorship in the DNS ".org" zone would still be effective.
1718 @node SOA SRV PTR and MX
1719 @subsubsection SOA SRV PTR and MX
1721 The domain names in those records can, again, be either
1724 @item A zone relative name,
1725 @item A zkey name or
1729 The resolver will expand the zone relative name if possible.
1730 Note that when using MX records within GNS, the target mail
1731 server might still refuse to accept e-mails to the resulting
1732 domain as the name might not match. GNS-enabled mail clients
1733 should use the ZKEY zone as the destination hostname and
1734 GNS-enabled mail servers should be configured to accept
1735 e-mails to the ZKEY-zones of all local users.
1738 @subsubsection PLACE
1740 Record type for a social place.
1743 @subsubsection PHONE
1745 Record type for a phone (of CONVERSATION).
1748 @subsubsection ID ATTR
1750 Record type for identity attributes (of IDENTITY).
1753 @subsubsection ID TOKEN
1755 Record type for an identity token (of IDENTITY-TOKEN).
1757 @node ID TOKEN METADATA
1758 @subsubsection ID TOKEN METADATA
1760 Record type for the private metadata of an identity token (of IDENTITY-TOKEN).
1763 @subsubsection CREDENTIAL
1765 Record type for credential.
1768 @subsubsection POLICY
1770 Record type for policies.
1773 @subsubsection ATTRIBUTE
1775 Record type for reverse lookups.
1778 @subsubsection ABE KEY
1780 Record type for ABE records.
1783 @subsubsection ABE MASTER
1785 Record type for ABE master keys.
1787 @node RECLAIM OIDC CLIENT
1788 @subsubsection RECLAIM OIDC CLIENT
1790 Record type for reclaim OIDC clients.
1792 @node RECLAIM OIDC REDIRECT
1793 @subsubsection RECLAIM OIDC REDIRECT
1795 Record type for reclaim OIDC redirect URIs.
1797 @node Synchronizing with legacy DNS
1798 @subsection Synchronizing with legacy DNS
1800 If you want to support GNS but the master database for a zone
1801 is only available and maintained in DNS, GNUnet includes the
1802 @command{gnunet-zoneimport} tool to monitor a DNS zone and
1803 automatically import records into GNS. Today, the tool does
1804 not yet support DNS AF(X)R, as we initially used it on the
1805 ``.fr'' zone which does not allow us to perform a DNS zone
1806 transfer. Instead, @command{gnunet-zoneimport} reads a list
1807 of DNS domain names from @code{stdin}, issues DNS queries for
1808 each, converts the obtained records (if possible) and stores
1809 the result in the namestore.
1811 @image{images/gns,6in,, picture of DNS-GNS data flow}
1813 The zonemaster service then takes the records from the namestore,
1814 publishes them into the DHT which makes the result available to the
1815 GNS resolver. In the GNS configuration, non-local zones can be
1816 configured to be intercepted by specifying ``.tld = PUBLICKEY'' in the
1817 configuration file in the ``[gns]'' section.
1819 Note that the namestore by default also populates the namecache.
1820 This pre-population is cryptographically expensive. Thus, on
1821 systems that only serve to import a large (millions of records)
1822 DNS zone and that do not have a local gns service in use, it
1823 is thus advisable to disable the namecache by setting the
1824 option ``DISABLE'' to ``YES'' in section ``[namecache]''.
1826 @node Migrating an existing DNS zone into GNS
1827 @subsection Migrating an existing DNS zone into GNS
1829 Ascension is a tool to migrate existing DNS zones into GNS.
1831 @xref{Migrating existing DNS zones into GNS}, for installation instructions and
1832 further information about Ascension.
1834 Compared to the gnunet-zoneimport tool it strictly uses AXFR or IXFR depending
1835 on whether or not there exists a SOA record for the zone. If that is the case it
1836 will take the serial as a reference point and request the zone. The server will
1837 either answer the IXFR request with a correct incremental zone or with the
1838 entire zone, which depends on the server configuration.
1840 After installing the tool according to the README file you have the following
1846 ascension <domain> [-d] [-p] [-s] [--minimum-ttl=<ttl>] \
1848 ascension <domain> <port> [-d] [-p] [-s] \
1849 [--minimum-ttl=<ttl>] [--dry-run]
1850 ascension <domain> -n <transferns> [-d] [-p] \
1851 [-s] [--minimum-ttl=<ttl>] [--dry-run]
1852 ascension <domain> -n <transferns> <port> [-d] \
1853 [-p] [-s] [--minimum-ttl=<ttl>] [--dry-run]
1854 ascension -p | --public
1855 ascension -d | --debug
1856 ascension -s | --standalone
1857 ascension -h | --help
1858 ascension -v | --version
1861 <domain> Domain to migrate
1862 <port> Port for zone transfer
1863 <transferns> DNS Server that does the zone transfer
1864 --minimum-ttl=<ttl> Minimum TTL for records to migrate \
1866 --dry-run Only try if a zone transfer is allowed
1867 -p --public Make records public on the DHT
1868 -s --standalone Run ascension once
1869 -d --debug Enable debugging
1870 -h --help Show this screen.
1871 -v --version Show version.
1874 Before you can migrate any zone though, you need to start a local GNUnet peer:
1879 To migrate the Syrian top level domain - one of the few top level domains that
1880 support zone transfers - into GNS use the following command:
1883 $ ascension sy. -n ns1.tld.sy. -p
1886 The -p flag will tell GNS to put these records on the DHT so that other users
1887 may resolve these records by using the public key of the zone.
1889 Once the zone is migrated, Ascension will output a message telling you, that it
1890 will refresh the zone after the time has elapsed. You can resolve the names in
1891 the zone directly using GNS or if you want to use it with your browser, check
1892 out the GNS manual section. @ref{Configuring the GNU Name System}. To resolve
1893 the records from another system you need the respective zones PKEY. To get the
1894 zones public key, you can run the following command:
1897 $ gnunet-identity -dqe sy
1900 Where "sy" is the name of the zone you want to migrate.
1902 You can share the PKEY of the zone with your friends. They can then resolve
1903 records in the zone by doing a lookup replacing the zone label with your PKEY:
1906 $ gnunet-gns -t SOA -u "$PKEY"
1909 The program will continue to run as a daemon and update once the refresh time
1910 specified in the zones SOA record has elapsed.
1912 DNSCurve style records are supported in the latest release and they are added
1913 as a PKEY record to be referred to the respective GNS public key. Key
1914 distribution is still a problem but provided someone else has a public key
1915 under a given label it can be looked up.
1917 There is an unofficial Debian package called python3-ascension that adds a
1918 system user ascension and runs a GNUnet peer in the background.
1920 Ascension-bind is also an unofficial Debian package that on installation checks
1921 for running DNS zones and whether or not they are transferable using DNS zone
1922 transfer (AXFR). It asks the administrator which zones to migrate into GNS and
1923 installs a systemd unit file to keep the zone up to date. If you want to
1924 migrate different zones you might want to check the unit file from the package
1927 @node reclaimID Identity Provider
1928 @section reclaimID Identity Provider
1930 The reclaimID Identity Provider (IdP) is a decentralized IdP service.
1931 It allows its users to manage and authorize third parties to access
1932 their identity attributes such as email or shipping addresses.
1934 It basically mimics the concepts of centralized IdPs, such as those
1935 offered by Google or Facebook.
1936 Like other IdPs, reclaimID features an (optional) OpenID-Connect
1937 1.0-compliant protocol layer that can be used for websites to
1938 integrate reclaimID as an Identity Provider with little effort.
1941 * Managing Attributes::
1942 * Sharing Attributes with Third Parties::
1943 * Revoking Authorizations of Third Parties::
1947 @node Managing Attributes
1948 @subsection Managing Attributes
1950 Before adding attributes to an identity, you must first create an ego:
1953 $ gnunet-identity -C "user"
1956 Henceforth, you can manage a new user profile of the user ``user''.
1958 To add an email address to your user profile, simply use the @command{gnunet-reclaim} command line tool::
1961 $ gnunet-reclaim -e "user" -a "email" -V "username@@example.gnunet"
1964 All of your attributes can be listed using the @command{gnunet-reclaim}
1965 command line tool as well:
1968 $ gnunet-reclaim -e "user" -D
1971 Currently, and by default, attribute values are interpreted as plain text.
1972 In the future there might be more value types such as X.509 certificate credentials.
1974 @node Sharing Attributes with Third Parties
1975 @subsection Sharing Attributes with Third Parties
1977 If you want to allow a third party such as a website or friend to access to your attributes (or a subset thereof) execute:
1980 $ gnunet-reclaim -e "user" -r "PKEY" -i "attribute1,attribute2,..."
1983 Where "PKEY" is the public key of the third party and "attribute1,attribute2,..." is a comma-separated list of attribute names, such as "email,name,...", that you want to share.
1985 The command will return a "ticket" string.
1986 You must give this "ticket" to the requesting third party.
1988 The third party can then retrieve your shared identity attributes using:
1991 $ gnunet-reclaim -e "friend" -C "ticket"
1994 Where "friend" is the name for "user" that the requesting party is using.
1995 This will retrieve and list the shared identity attributes.
1996 The above command will also work if the user is currently offline since the attributes are retrieved from GNS.
1997 Further, the "ticket" can be re-used later to retrieve up-to-date attributes in case "friend" has changed the value(s). For instance, because his email address changed.
1999 To list all given authorizations (tickets) you can execute:
2001 $ gnunet-reclaim -e "friend" -T (TODO there is only a C and REST API for this at this time)
2005 @node Revoking Authorizations of Third Parties
2006 @subsection Revoking Authorizations of Third Parties
2008 If you want to revoke the access of a third party to your attributes you can execute:
2011 $ gnunet-reclaim -e "user" -R "ticket"
2014 This will prevent the third party from accessing the attribute in the future.
2015 Please note that if the third party has previously accessed the attribute, there is not way in which the system could have prevented the thiry party from storing the data.
2016 As such, only access to updated data in the future can be revoked.
2017 This behaviour is _exactly the same_ as with other IdPs.
2019 @node OpenID Connect
2020 @subsection OpenID Connect
2022 There is an OpenID Connect API for use with reclaimID.
2023 However, its use is quite complicated to setup.
2024 As a proof-of-concept, you can look at https://gitlab.com/reclaimid.
2026 In the PoC and by convention for reclaimID, the OpenID Connect Endpoints are
2030 http://api.reclaim/openid/authorize
2031 http://api.reclaim/openid/token
2032 http://api.reclaim/openid/userinfo
2033 http://api.reclaim/openid/login
2036 The token endpoint is protected using HTTP basic authentication.
2037 You can authenticate using any username and the password configured under:
2040 $ gnunet-config -s reclaim-rest-plugin -o PSW
2043 The authorize endpoint is protected using a Cookie which can be obtained through
2044 a request against the login endpoint.
2045 This flow is meant to be used in the context of the OpenID Connect authorization
2046 flow to collect user consent interactively.
2047 Without a Cookie, the authorize endpoint redirects to a URI configured under:
2050 $ gnunet-config -s reclaim-rest-plugin -o ADDRESS
2053 Our PoC includes a user interface (https://gitlab.com/reclaimid) which
2054 integrates this process is an OpenID Connect compatible fashion.
2056 The token endpoint is protected using OAuth2 and expects the grant
2057 which is retrieved from the authorization endpoint according to the standard.
2059 The userinfo endpoint is protected using OAuth2 and expects a bearer access
2060 token which is retrieved from a token request.
2062 In order to create and register a client you need to execute the following
2066 $ gnunet-identity -C <client_name>
2067 $ gnunet-namestore -z <client_name> -a -n "@@" -t RECLAIM_OIDC_REDIRECT -V <redirect_uri> -e 1d -p
2068 $ gnunet-namestore -z <client_name> -a -n "@@" -t RECLAIM_OIDC_CLIENT -V "My OIDC Client" -e 1d -p
2071 The client_id will be the public key of the client.
2072 As a redirect URI, you may use any globally unique DNS or GNS URI.
2073 The client description will be displayed to the user on authorization.
2075 Any website or relying party must use the endpoint
2076 https://api.reclaim/openid/authorize in its authorization redirects, e.g.
2079 <a href="https://api.reclaim/openid/authorize?client_id=<PKEY>\
2081 &redirect_uri=<redirect_uri>\
2082 &nonce=<random>">Login</a>
2085 This will direct the user's browser onto his local reclaimID instance.
2086 After giving consent, you will be provided with the OpenID Connect authorization
2087 code according to the specifications at your provided redirect URI.
2088 The example code for the PoC website can be found at https://gitlab.com/reclaimid/demo.
2090 @node Using the Virtual Public Network
2091 @section Using the Virtual Public Network
2094 * Setting up an Exit node::
2095 * Fedora and the Firewall::
2096 * Setting up VPN node for protocol translation and tunneling::
2099 Using the GNUnet Virtual Public Network (VPN) application you can
2100 tunnel IP traffic over GNUnet. Moreover, the VPN comes
2101 with built-in protocol translation and DNS-ALG support, enabling
2102 IPv4-to-IPv6 protocol translation (in both directions).
2103 This chapter documents how to use the GNUnet VPN.
2105 The first thing to note about the GNUnet VPN is that it is a public
2106 network. All participating peers can participate and there is no
2107 secret key to control access. So unlike common virtual private
2108 networks, the GNUnet VPN is not useful as a means to provide a
2109 "private" network abstraction over the Internet. The GNUnet VPN
2110 is a virtual network in the sense that it is an overlay over the
2111 Internet, using its own routing mechanisms and can also use an
2112 internal addressing scheme. The GNUnet VPN is an Internet
2113 underlay --- TCP/IP applications run on top of it.
2115 The VPN is currently only supported on GNU/Linux systems.
2116 Support for operating systems that support TUN (such as FreeBSD)
2117 should be easy to add (or might not even require any coding at
2118 all --- we just did not test this so far). Support for other
2119 operating systems would require re-writing the code to create virtual
2120 network interfaces and to intercept DNS requests.
2122 The VPN does not provide good anonymity. While requests are routed
2123 over the GNUnet network, other peers can directly see the source
2124 and destination of each (encapsulated) IP packet. Finally, if you
2125 use the VPN to access Internet services, the peer sending the
2126 request to the Internet will be able to observe and even alter
2127 the IP traffic. We will discuss additional security implications
2128 of using the VPN later in this chapter.
2130 @node Setting up an Exit node
2131 @subsection Setting up an Exit node
2133 Any useful operation with the VPN requires the existence of an exit
2134 node in the GNUnet Peer-to-Peer network. Exit functionality can only
2135 be enabled on peers that have regular Internet access. If you want
2136 to play around with the VPN or support the network, we encourage
2137 you to setup exit nodes. This chapter documents how to setup an
2140 There are four types of exit functions an exit node can provide,
2141 and using the GNUnet VPN to access the Internet will only work
2142 nicely if the first three types are provided somewhere in
2143 the network. The four exit functions are:
2146 @item DNS: allow other peers to use your DNS resolver
2147 @item IPv4: allow other peers to access your IPv4 Internet connection
2148 @item IPv6: allow other peers to access your IPv6 Internet connection
2149 @item Local service: allow other peers to access a specific TCP or
2150 UDP service your peer is providing
2153 By enabling "exit" in gnunet-setup and checking the respective boxes
2154 in the "exit" tab, you can easily choose which of the above exit
2155 functions you want to support.
2157 Note, however, that by supporting the first three functions you will
2158 allow arbitrary other GNUnet users to access the Internet via your
2159 system. This is somewhat similar to running a Tor exit node. The
2160 Torproject has a nice article about what to consider if you want
2161 to do this here. We believe that generally running a DNS exit node
2162 is completely harmless.
2164 The exit node configuration does currently not allow you to restrict the
2165 Internet traffic that leaves your system. In particular, you cannot
2166 exclude SMTP traffic (or block port 25) or limit to HTTP traffic using
2167 the GNUnet configuration. However, you can use your host firewall to
2168 restrict outbound connections from the virtual tunnel interface. This
2169 is highly recommended. In the future, we plan to offer a wider range
2170 of configuration options for exit nodes.
2172 Note that by running an exit node GNUnet will configure your kernel
2173 to perform IP-forwarding (for IPv6) and NAT (for IPv4) so that the
2174 traffic from the virtual interface can be routed to the Internet.
2175 In order to provide an IPv6-exit, you need to have a subnet routed
2176 to your host's external network interface and assign a subrange of
2177 that subnet to the GNUnet exit's TUN interface.
2179 When running a local service, you should make sure that the local
2180 service is (also) bound to the IP address of your EXIT interface
2181 (i.e. 169.254.86.1). It will NOT work if your local service is
2182 just bound to loopback. You may also want to create a "VPN" record
2183 in your zone of the GNU Name System to make it easy for others to
2184 access your service via a name instead of just the full service
2185 descriptor. Note that the identifier you assign the service can
2186 serve as a passphrase or shared secret, clients connecting to the
2187 service must somehow learn the service's name. VPN records in the
2188 GNU Name System can make this easier.
2190 @node Fedora and the Firewall
2191 @subsection Fedora and the Firewall
2194 When using an exit node on Fedora 15, the standard firewall can
2195 create trouble even when not really exiting the local system!
2196 For IPv4, the standard rules seem fine. However, for IPv6 the
2197 standard rules prohibit traffic from the network range of the
2198 virtual interface created by the exit daemon to the local IPv6
2199 address of the same interface (which is essentially loopback
2200 traffic, so you might suspect that a standard firewall would
2201 leave this traffic alone). However, as somehow for IPv6 the
2202 traffic is not recognized as originating from the local
2203 system (and as the connection is not already "established"),
2204 the firewall drops the traffic. You should still get ICMPv6
2205 packets back, but that's obviously not very useful.
2207 Possible ways to fix this include disabling the firewall (do you
2208 have a good reason for having it on?) or disabling the firewall
2209 at least for the GNUnet exit interface (or the respective
2210 IPv4/IPv6 address range). The best way to diagnose these kinds
2211 of problems in general involves setting the firewall to REJECT
2212 instead of DROP and to watch the traffic using wireshark
2213 (or tcpdump) to see if ICMP messages are generated when running
2214 some tests that should work.
2216 @node Setting up VPN node for protocol translation and tunneling
2217 @subsection Setting up VPN node for protocol translation and tunneling
2220 The GNUnet VPN/PT subsystem enables you to tunnel IP traffic over the
2221 VPN to an exit node, from where it can then be forwarded to the
2222 Internet. This section documents how to setup VPN/PT on a node.
2223 Note that you can enable both the VPN and an exit on the same peer.
2224 In this case, IP traffic from your system may enter your peer's VPN
2225 and leave your peer's exit. This can be useful as a means to do
2226 protocol translation. For example, you might have an application that
2227 supports only IPv4 but needs to access an IPv6-only site. In this case,
2228 GNUnet would perform 4to6 protocol translation between the VPN (IPv4)
2229 and the Exit (IPv6). Similarly, 6to4 protocol translation is also
2230 possible. However, the primary use for GNUnet would be to access
2231 an Internet service running with an IP version that is not supported
2232 by your ISP. In this case, your IP traffic would be routed via GNUnet
2233 to a peer that has access to the Internet with the desired IP version.
2235 Setting up an entry node into the GNUnet VPN primarily requires you
2236 to enable the "VPN/PT" option in "gnunet-setup". This will launch the
2237 "gnunet-service-vpn", "gnunet-service-dns" and "gnunet-daemon-pt"
2238 processes. The "gnunet-service-vpn" will create a virtual interface
2239 which will be used as the target for your IP traffic that enters the
2240 VPN. Additionally, a second virtual interface will be created by
2241 the "gnunet-service-dns" for your DNS traffic. You will then need to
2242 specify which traffic you want to tunnel over GNUnet. If your ISP only
2243 provides you with IPv4 or IPv6-access, you may choose to tunnel the
2244 other IP protocol over the GNUnet VPN. If you do not have an ISP
2245 (and are connected to other GNUnet peers via WLAN), you can also
2246 choose to tunnel all IP traffic over GNUnet. This might also provide
2247 you with some anonymity. After you enable the respective options
2248 and restart your peer, your Internet traffic should be tunneled
2249 over the GNUnet VPN.
2251 The GNUnet VPN uses DNS-ALG to hijack your IP traffic. Whenever an
2252 application resolves a hostname (i.e. 'gnunet.org'), the
2253 "gnunet-daemon-pt" will instruct the "gnunet-service-dns" to intercept
2254 the request (possibly route it over GNUnet as well) and replace the
2255 normal answer with an IP in the range of the VPN's interface.
2256 "gnunet-daemon-pt" will then tell "gnunet-service-vpn" to forward all
2257 traffic it receives on the TUN interface via the VPN to the original
2260 For applications that do not use DNS, you can also manually create
2261 such a mapping using the gnunet-vpn command-line tool. Here, you
2262 specify the desired address family of the result (i.e. "-4"), and the
2263 intended target IP on the Internet ("-i 131.159.74.67") and
2264 "gnunet-vpn" will tell you which IP address in the range of your
2265 VPN tunnel was mapped.
2267 @command{gnunet-vpn} can also be used to access "internal" services
2268 offered by GNUnet nodes. So if you happen to know a peer and a
2269 service offered by that peer, you can create an IP tunnel to
2270 that peer by specifying the peer's identity, service name and
2271 protocol (--tcp or --udp) and you will again receive an IP address
2272 that will terminate at the respective peer's service.