These are the highlights of new features or additions to existing features in v4.2.x.
New configuration option for attaching server sessions to client sessions
Even though Traffic Server always supported sharing origin server sessions between client sessions, a server session would by default be associated with a Keep-Alive client session for the duration of that client session. This was configurable by limiting the number of server connections (proxy.config.http.server_max_connections). To decouple this overloaded semantics, a new configuration option has been created:
CONFIG proxy.config.http.attach_server_session_to_client INT 0
The default is "0", which means we no longer attach the server sessions to the client by default. This is a change from previous versions of Apache Traffic Server, but it's a reasonable change since it changes what should be considered a broken behavior. Changing this configuration to "1" will not restore the old behavior, but will instead always attach the server sessions regardless of what proxy.config.http.server_max_connections is set to.
TLS 1.1 and 1.2 Configurations
There are two new options to turn off or on TLS 1.1 and TLS 1.2. By default TLS 1.2 is off (value of 0), for now, because of a problem with TLS 1.2 crashing in openssl 1.0.1a and 1.0.1e. There is an open issue with openssl http://rt.openssl.org/Ticket/Display.html?id=3200.
CONFIG proxy.config.ssl.TLSv1_1 INT 1
CONFIG proxy.config.ssl.TLSv1_2 INT 0