Even though I have forwarded requests to each machine's SSH port
What exactly does that mean?
Yes normally when you ssh a machine internally you don't need
rerouting or forwarding
I am not saying I have forwarded the internal requests, I forwarded
requests coming from the internet
for instance using clients such as putty etc..
But no connection is allowed either internally or externally.
Well, you can forward the official SSH port 22 only once to one of the
internal machines.
I am pretty sure there is some error in your port forwarding setup. To
prove this, try to stop squid (not the whole server, just the squid
process) and re-check ssh access. If the problems remain, you have an
error in your firewalling/forwarding/gateway setup.
JC