Use lobby.brierie.net which allows you to join from any client from 1.7.10 - 1.12.2!
At Brierie Servers we have almost all the FTB modpacks. We strive to give the best gaming experience when it comes to latency and uptime. Brierie Servers have been hosting minecraft servers for over 5 years racking up a lot of knowledge in the field of hosting modded servers.
To find all our servers you can join just go to our website