You should indeed use This patch on your jazz2.exe, or you will be nowhere with online gaming nowadays.

As for the Zeal servers, players can see the password on This site. It's THE main site used for ladder seasons and other kinds of tournaments. If you log in with a registered account you will probably see the passwords appear at the right of the page + the standard player "third" admin password. Which gives you semi-access to the server. This allows you to arrange your own match in this dedicated server using the JJ2+ commands with a certain amount of commands available in your admin group.
(you can find the list of commands Here. To adminlogin you should use the /login command in the text field box in the server).