=head1 NAME
-SSL_CTX_new - create a new SSL_CTX object as framework for TLS/SSL enabled functions
+SSL_CTX_new, SSLv2_method, SSLv2_server_method, SSLv2_client_method, SSLv3_method, SSLv3_server_method, SSLv3_client_method, TLSv1_method(void), TLSv1_server_method(void), TLSv1_client_method, TLSv1_1_method, TLSv1_1_server_method, TLSv1_1_client_method, SSLv23_method, SSLv23_server_method, SSLv23_client_method - create a new SSL_CTX object as framework for TLS/SSL enabled functions
=head1 SYNOPSIS
A TLS/SSL connection established with these methods will only understand
the SSLv2 protocol. A client will send out SSLv2 client hello messages
and will also indicate that it only understand SSLv2. A server will only
-understand SSLv2 client hello messages.
+understand SSLv2 client hello messages. The SSLv2 protocol is deprecated
+and very broken: its use is B<strongly> discouraged.
=item SSLv3_method(void), SSLv3_server_method(void), SSLv3_client_method(void)
compatibility reasons, see SSLv23_*_method(). It will also not understand
SSLv3 client hello messages.
+=item TLSv1_1_method(void), TLSv1_1_server_method(void), TLSv1_1_client_method(void)
+
+A TLS/SSL connection established with these methods will only understand the
+TLSv1.1 protocol. A client will send out TLSv1.1 client hello messages
+and will indicate that it only understands TLSv1.1. A server will only
+understand TLSv1.1 client hello messages. This especially means, that it will
+not understand SSLv2 client hello messages which are widely used for
+compatibility reasons, see SSLv23_*_method(). It will also not understand
+SSLv3 client hello messages.
+
=item SSLv23_method(void), SSLv23_server_method(void), SSLv23_client_method(void)
-A TLS/SSL connection established with these methods will understand the SSLv2,
-SSLv3, and TLSv1 protocol. A client will send out SSLv2 client hello messages
-and will indicate that it also understands SSLv3 and TLSv1. A server will
-understand SSLv2, SSLv3, and TLSv1 client hello messages. This is the best
-choice when compatibility is a concern.
+A TLS/SSL connection established with these methods may understand the SSLv2,
+SSLv3, TLSv1, TLSv1.1 and TLSv1.2 protocols.
+
+If the cipher list does not contain any SSLv2 ciphersuites (the default
+cipher list does not) or extensions are required (for example server name)
+a client will send out TLSv1 client hello messages including extensions and
+will indicate that it also understands TLSv1.1, TLSv1.2 and permits a
+fallback to SSLv3. A server will support SSLv3, TLSv1, TLSv1.1 and TLSv1.2
+protocols. This is the best choice when compatibility is a concern.
+
+If any SSLv2 ciphersuites are included in the cipher list and no extensions
+are required then SSLv2 compatible client hellos will be used by clients and
+SSLv2 will be accepted by servers. This is B<not> recommended due to the
+insecurity of SSLv2 and the limited nature of the SSLv2 client hello
+prohibiting the use of extensions.
=back
The list of protocols available can later be limited using the SSL_OP_NO_SSLv2,
-SSL_OP_NO_SSLv3, SSL_OP_NO_TLSv1 options of the B<SSL_CTX_set_options()> or
-B<SSL_set_options()> functions. Using these options it is possible to choose
-e.g. SSLv23_server_method() and be able to negotiate with all possible
-clients, but to only allow newer protocols like SSLv3 or TLSv1.
+SSL_OP_NO_SSLv3, SSL_OP_NO_TLSv1, SSL_OP_NO_TLSv1_1 and SSL_OP_NO_TLSv1_2
+options of the SSL_CTX_set_options() or SSL_set_options() functions.
+Using these options it is possible to choose e.g. SSLv23_server_method() and
+be able to negotiate with all possible clients, but to only allow newer
+protocols like TLSv1, TLSv1.1 or TLS v1.2.
+
+Applications which never want to support SSLv2 (even is the cipher string
+is configured to use SSLv2 ciphersuites) can set SSL_OP_NO_SSLv2.
SSL_CTX_new() initializes the list of ciphers, the session cache setting,
-the callbacks, the keys and certificates, and the options to its default
+the callbacks, the keys and certificates and the options to its default
values.
=head1 RETURN VALUES