Re: something is randomly closing ssh-tunnels (was: ipfilter randomly dropping..)

[Darren Reed <darrenr%netbsd.org@localhost>]

On 24/06/2014 10:39 PM, Darren Reed wrote:
> On 23/06/2014 8:24 PM, Petar Bogdanovic wrote:
>> ...  * sshd bails on a failed write() with ENETUNREACH
> So the problem is this:
> * sshd tries to write to the socket, gets ENETUNREACH
>
> and then exits leading to the FIN packets being transmitted as the socket
> is closed down in the normal course of things but by the time it is doing
> the exit the network path has restored.
>
> For ICMP packets to cause this, you would need to see many of them.
>

Oh, I forgot, there are internal code paths in ipfilter/npf that can
return ENETUNREACH.

If you are using NetBSD 6 with ipfilter, comparing the output of this:

ipfstat | grep 'block reason'

from before and after might be illuminating.

Or maybe just compare the entire output of "ipfstat" and "ipfstat -s"
from before and after.

Kind Regards,
Darren