Re: normal behavior for openssh time outs?

Jack Howarth wrote:
>     I have noticed for sometime now that openssh 3.6p1 which ships
> with MacOS X 10.3 has the following behavior. If I connect from a
> terminal window to a remote sshd server through a firewall that 
> times out ssh connections when idle for longer than a certain time,
> the terminal window which I ran the client in becomes unusable. That
> is if I connect with ssh, leave the ssh connection idle for long
> enough for the firewall to terminate the connection and then try to
> type in the ssh program, I find the ssh program in that terminal
> window is non-responsive. In particular, I can't use crtl-D to 
> terminate the ssh session but have to close the terminal window
> entirely.

When you hit ctrl-d it sends an EOF to the remote shell, which exits, 
causing the SSH connection to close.  If the connection is disrupted then 
this doesn't occur.

> Is this normal expected behavior for ssh...that once the
> connection to the remote sshd server is severed that you can't use
> ctrl-D to get out of the ssh program? Thanks in advance for any
> clarifications on this question.

Use ssh's escape character to close the session ("~." by default, but it's 
only recognised at the start of a line).

Newer versions of OpenSSH have a client-side keepalive 
(ServerAliveInterval) which is useful for preventing firewall session 
timeouts.

--
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.