[CentOS] problem on exceptional quit

Mon Oct 12 17:10:14 UTC 2015
Gordon Messmer <gordon.messmer at gmail.com>

On 10/10/2015 11:25 PM, Hua Wang wrote:
> I am not sure if we can not send attachments to the mailing list. There were quite a lot replies before, but I got nothing back since attachements was added. I will remove the attachments and send it again.

You can use services like pastebin.com to temporarily post your logs.  I 
wouldn't recommend posting the whole "secure" log.  The output of dmesg 
might be helpful, but you can probably just read it and determine 
whether or not there's anything related to your NIC or to networking.

arping and ifconfig don't show any conflicts or errors.  It's still 
possible that there's a conflict with a device that's not online all of 
the time, but that'll be hard to track down.

At this point, I think we've exhausted a lot of the simple stuff. The 
next thing I'd do would be to run tcpdump on your client and watch all 
of the traffic to and from the server, and any ICMP. When the connection 
is interrupted, the last few packets should show the cause.  I'd expect 
you to see either a TCP reset or one of a few ICMP messages.  So, open a 
terminal, start a tcpdump, and let it run until your ssh connection (in 
another terminal, obviously) is reset.  Use Ctrl+C to stop tcpdump.

# tcpdump -nn host or icmp