[K12OSN] ssh access dropping out

[Krsnendu dasa]

This is what happens.
I ssh into my K12LTSP-6 server.
Sometimes if I don't give it input for a few seconds it freezes and I
have to reconnect.
This happens when I uses ssh from another linux machine, putty and
winscp from windows.
It also happens from LAN and when accessing from home through the internet.
I also noticed this behaviour when accessing a debian virtual machine
running on K12LTSP.
I haven't noticed this behaviour so much using NX

Any clues as to what might be happening?