okay, just FYI
TechnicServer prefer IPv6, so if your server is IPv6 capable you HAVE TO use IPv6!
make sure it's working before you try it first time, otherwise it wont work, TechnicServer wont use IPv6 if you add it later, you have to switch domain/subdomain to make it work again. The check for IPv6 seem to be only on the first connect, so if you miss that... you probably wont be able to use your preferred domain!
For me its a big BUG.