ssh connections stopped working

[David Fletcher]

This is driving me nuts!

In my home network I have a server running Ubuntu Server, my own desktop
and my son's desktop. Both desktops and my laptop are running Maverick.

I just built him a new PC which we hoped to get set up tonight but I
can't get the data off the HDD in his current one. I want to use rsync
across the network to copy everything to a HDD in either my desktop or
the server I don't care which, but it just won't go.

I know for sure that rsync used to work with his machine because there
is a previous backup on it that was done using rsync from my desktop to
his.

Tonight, I can ssh into the server no problem from my desktop, ping to
his desktop works but ssh both to and from his desktop just fails and
times out.

Nobody has installed firewalls on anything, so I just don't know where
to start.

Curiously, I am sure the laptop also used to be able to ssh into the
server via the WiFi but now does not. Same time out message.

By switching some cables I have eliminated the possibility of the router
blocking port 22.

Can anybody give me a clue, please?

Dave