# Bridge Mode
A common feature of COTS Wi-Fi routers is to be able to set the router
-to bridge mode, where the router stops acting like a router (layer 3
-device) and starts acting like an ethernet switch (layer 2
-device). LibreCMC does not actually have a bridge mode, but the same
-effect is achievable with a few easy steps.
+to bridge mode, where the devices stops acting like an IP router
+(layer 3) and starts acting like an ethernet switch (layer
+2). LibreCMC does not actually have a bridge mode, but the same effect
+is achievable with two easy steps.
-1. Add the LAN ethernet port to the LAN bridge interface
+1. Add the WAN ethernet port to the LAN bridge interface
2. Set the DHCP server to ignore the LAN interface
-## Adjust LAN bridge interface
+## Adjust the LAN bridge interface
-Go to Network >> Interfaces page and press the EDIT button next to LAN
-Network. Select the Physical Settings tab.
+Go to the Network >> Interfaces page and press the EDIT button next to
+the LAN Network. Select the Physical Settings tab.
Place a checkmark in the box for the "eth0" interface for wan and
wan6. (I suppose the interface name might vary amongst different
-routers.
+routers.)
You can also check the box for Enable STP if desired. There doesn't
-seem to be any downside from this, though I suppose it would use more
-CPU cycles and memory. STP is a protocol intended to prevent
-communication loops from forming in a network of layer 2 switches.
+seem to be any downside from this, though I suppose it would use a
+little more CPU cycles and memory. STP is a protocol intended to
+prevent infinite communication loops from forming in a network of
+layer 2 switches.
## Adjust DHCP server settings
On the same page, scroll down a little to the DHCP Server section. In
the General Setup tab, check the "Ignore interface" box.
+
+
+
+Save and apply your changes.
+
+## Communicating with LibreCMC in "bridge mode"
+
+Now that the DHCP server is turned off, the next time you connect to
+the libreCMC device, you will not be able to communicate with it. You
+must set your connecting device manually to be on the same
+subnet. Since the default libreCMC LAN IP address is 192.168.10.1/24,
+it should work to set your connecting device to IP address
+192.168.10.2/24.On Gnu/Linux systems, the command is usually `ip addr
+add 192.168.10.2/24 dev eth0` or `dev wlan0` if connecting wirelessly.
+
+Alternatively, you may set the libreCMC device to receive an IP
+address from another DHCP server on your network: go to back to the
+Network >> Interfaces page, press the EDIT button again next to the
+LAN Network, select the General Setup tab, and switch the Protocol
+from "Static address" to "DHCP client". (It seems that in LibreCMC,
+bridging the LAN interface to the WAN port disables the operation of
+the DHCP client on the WAN interface.) Of course, if you do this, be
+sure that your DHCP server has reserved a memorable IP address for the
+LibreCMC device's MAC address, so you don't have trouble finding it.
+
+
+
+## Advanced
+
+These adjustments are not required, but they lead to a configuration
+which will be more consistent and have cleaner logs.
+
+### Disabling odhcpd (DHCP daemon)
+
+In bridge mode, you aren't going to want to serve DHCP out any
+interface. So you might as well just shut down the whole DHCP
+server. Log in via SSH, and run the commands:
+
+```
+/etc/init.d/odhcpd stop
+/etc/init.d/odhcpd disable
+```
+
+### Delete the WAN(6) interfaces
+
+From `Network` >> `Interfaces`, you can delete the WAN and WAN6
+interfaces. See also the "Add a LAN6 interface" section below.
+
+### Delete the WAN Firewall Zone
+
+From `Network` >> `Firewall` you can delete the WAN zone. If you do
+need a WAN firewall, then you should not be running in bridge mode in
+the first place.
+
+### Add a LAN6 Interface
+
+If you have IPv6 access, you will want an interface which receives an
+IPv6 address. From `Network` >> `Interfaces` create a new interface
+called `LAN6` with `Protocol` set to `DHCPv6 client`.
+
+You will likely also want to disable `odhcpd` (see above). Otherwise
+your logs can get filled up with unnecessary IPv6 related messages, as
+libreCMC tries to act like an IPv6 router. `odhcpd` normally handles
+DHCPv6 as well as IPv6 Router Advertisements.
projects / librecmc / librecmc.git / blobdiff