So I was recently working on a project to bring several servers into a single consolidated server that would allow my friends to join me, play on servers, but not have to have my desktop running 24/7 for that to happen. So I bought a server to run MineOS on but I want to run multiple versions of minecraft, including some serious changes in version (FTB/Tekkit) all the way to Vanilla. So during testing I was working with a vanilla server and a copy of the tekkit server. Once I finally got past the firewall issues (of which you can find the fix here) I ran into an issue with connecting to my vanilla server on a non-standard port (25564 and 25563). Well I found out something interesting, the tekkit game seems to be fine with connecting on the default port (25565) but not on alternate ports when connecting to a newer version of the game on those other ports. So I received an end of stream error from minecraft in tekkit while connecting.
Run Vanilla minecraft launcher with vanilla minecraft games and tekkit launcher for tekkit games.
Dumb... I know.... this took me a while to fix so I wanted to document it. There does seem to be multiple other possible issues with end of stream errors but this seemed to be the big one. Hope this helps someone else out.