On Fri, 14 Sep 2007, Greg Skinner wrote:
> After installing a NAT firewall/router, I noticed my ssh connections
> would drop when left idle for awhile. That never happened before -- I
> could go away from my machine for hours, and as long as client and
> server machines were up, with no network dynamics, everything would
> work fine when I returned. But is it TCP itself that's failing, or
> ssh interpreting the timeout as a non-transient condition, and telling
> TCP to close?
If that was truely the only change, then you have encountered one of the
idiot firewalls (which includes iptables on linux) which feel compelled to
drop idle connections from their connection state map. In the case of one
system I manage (with no NAT!), I got around the frustration by setting
the system tcp keep-alive interval. Some firewalls and NAT devices may be
configured to do this nasty ... some only when resources are constrained.
A temporary baby firewall (netgear) on my home network timesout but since
it isn't in my normal path, I live with it.
Another candidate is a bash feature which can be set to timeout after idle
time. But that leaves a message and in any case doesn't relate to your
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