Testing if a Milo client connection to a server is actually using encryption

Question

So, I'm using Eclipse Milo as a client. I wanted to test whether after establishing the connection, is the connection using encryption.

What is the best approach to do this?

Answer 1

To actually verify you need Wireshark. 

Wireshark understands OPC-UA. After configuration, you're connected to as UA and you'll see all the messages show up as "UA Secure Conversation Message" or something along those lines. When encryption is not used you can actually see the type, full structure, and content of every message between client and server