I'm setting up an Ubuntu 10.04 system; installed open-ssh. I'll call this box A. I also have an older box B with Debian. From A I can log into B via the usual way (ssh <user>@<IP>). The 1st attempt at this I was presented with the 'unknown host' warnings & elected to accept it.

However, from B when I try logging into A there is no response at all -- no warnings, nothing. I have to ctrl-C back to the prompt. I can successfully ping A from B though.

I CAN connect to A from a Windows box using PuTTY as an ssh client with all default settings. Once connected I can log in.

Why no response from A when trying to log in from B?

Thanks,
Ron

The first thing I would check is the allowed connection from hosts settings in my firewall configuration.