(Sorry if this question is a little basic or should go on a different SE site. Just let me know.)
I'm trying to learn about SIP. The problem is that I'm at the point where I don't know enough to try it myself to learn and sometimes I don't know enough to know what question to ask. I have seen that you can get a SIP account/username from websites like ekiga.net that will give you something like firstname.lastname@example.org that you can sign into with a client software like Ekiga (the software).
So, what things would I have to set up/do to make it so a can take a domain I have (like azendale.com) and set up an account like email@example.com have the SIP calls come in to Ekiga?
I'm not looking for step by step instructions so much, but instead to understand what pieces I need to set up/have in place for this to work.
I currently have an 12.04 server with a public IP (and IPv6 also), so I'm hoping that may sidestep issues I might have with NAT (I've heard that part can be tricky, and would be fine using only IPv6 if that makes it easier).