I presume that it doesn't support SNI (for SSL vhosts) as the underlying JVM doesn't support it for servers? (I couldn't see anything in the docs, and it says it uses the JVM's SSL support underneath.) One of the Google chaps said that SPDY required SNI when it was originally announced, so I was hopeful for a while.
Server Name Indication was added in Java 7, so I would expect that Netty supports it too, assuming you're running the latest version of the Java runtime.
In the server as well as the client?