Determine which TLS version was negotiated by client to a netty server

Question

I'm using a netty server. I don't want to enforce a specific TLS version for customers but I do want to know which TLS version is negotiated for each incoming connection to the server.

I can't find any way to determine that from the ssl handshake completion event or any other way to extract it from the handler.

Is it possible to get this information?

I don't see how it can be got from

• https://netty.io/4.0/api/io/netty/handler/ssl/SslHandshakeCompletionEvent.html
• https://netty.io/4.0/api/io/netty/handler/ssl/SslHandler.html

Thanks!

EDIT I poked around a bit and found "sslHandler.engine().getSession().getProtocol()" but still need to test and see if it works.

Answer 1

Just use sslHandler.engine().getSession().getProtocol() after the handshake completed.