I'm experiencing a very annoying session timeout issue. Its most often noticed when sshing to a host behind the firewall from off site. It doesn't seem to happen when the connection is initiated from another internal network, but that could be due to some bi-directional pass rules.
In any case, a ssh connection from outside to the DMZ will timeout after 5-10 minutes if idle.
You can use ServerAliveInterval in ~/.ssh/config (or ClientAliveInterval in /etc/ssh/sshd_config) to set up application-level keepalive packets in ssh. These will keep the connection open through firewalls with short timeouts.
-d
