I have an openssh-server running on Ubuntu 7.04. Frequently, the server just suddenly becomes impossible to connect to; existing and new putty clients see "Network error: connection refused" messages.

I found that i need to do "/etc/init.d/networking restart" to get past this problem without restarting sshd (Restarting sshd doesn't help). The auth.log file does not contain any pointers.

I'm clueless as to how a 'networking restart' fixes the issue of accepting TCP connections.

Would greatly appreciate any suggestions for a remedy to avoid this issue in the first place or any tips as to where to start looking.

Thanks
Vish

How is your server connected to external world? And did you try to ping the host when it rejects ssh?