Re: -current dropping ssh connections

On Jun 21, 2023, at 10:24, bob prohaska <fbsd@www.zefox.net> wrote:

> I've got a Pi4 running -current that seems to selectively drop ssh connections.

Only when the ssh has text streaming over it? Even when it
is idle? Any other types of context differences that lead
to observable differences of some type related to the
disconnects (vs. lack of them)?

> Connections running a shell seem to stay up, but a session running tip to a
> usb-serial adapter (FTDI TTL232R-3V3) seems go away within a few hours. 

The way that reads, ssh to a shell and then running tip in
that shell would stay up. (Does it?) tip is being run
without ssh running a shell? May be more detail about the
two contexts of establishing the connection is needed here?

> There don't seem to be any error messages on the console at all, the client 
> session simply reports 
> client_loop: send disconnect: Broken pipe
> 
> Searches through /var/log/sshd_debug.log find many transactions between
> the ssh client and the -current target host, but none seem to be error
> messages; all are either connection reports or disconnects by user.
> 
> This sort of behavior has been intermittent with aarch64 among both
> the Pi4 and a pair of Pi3s for some time, but now only the Pi4 is
> dropping connections. 
> 
> I've tried searching /var/log/sshd_debug.log for the keywords tip,
> ucom, the IP address of the NAT client used to connect and cuaU0.
> Are there other things worth looking for?
> 
> Right now I'm using in /etc/rc.conf the line
> sshd_flags="-E /var/log/sshd_debug.log"
> which is already quite verbose. Is there a better
> option that emphasizes errors over normal traffic?

I'm not likely to identify such, unfortunately.

===
Mark Millard
marklmi at yahoo.com