Hey guys! A really short, but extremely useful tutorial for you.
I couldn't make my server public for months. I've been trying, but I failed every time. But I got the solution! My 3724 TCP port was closed after forwarding, my ISP blocked it.
So!
If you've forwarded all of your ports, download the PFPortChecker program, and test all of your forwarded ports! If your ports are open - sorry for that - this guide is not for you.
If your 3724 port is closed even after forwarding it try this:
Forward another random port (I used 3112 here). Make sure it's open. Then go to your config files and find the logonserver/realmserver config (depends on your core). Find the line with "3724" port. Replace that port to your random made port (in our case its 3112). Save it, close it.
In your realmlist.wtf write your.dnsadress.domain:the random port
In my case it's: vanirity.dyndns-server.com:3112
This will solve the problem.
Tell your friends to write the same into their realmlist.wtf and they can join now. (They could in my case.)