scp hangs intermittendly

[skt_skt]

HP-UX 11.11
#ssh -V
OpenSSH_4.2p1-hpn, OpenSSL 0.9.7i 14 Oct 2005
HP-UX Secure Shell-A.04.20.004, HP-UX Secure Shell version


Here are the hung scp processes.
As we see here, there is a another process getting created with scp and looks like that process is hung and if that is causing the trouble

[A known sshd hang problem exists on the server(80p) and it happens once in three months(like that) and we need to bounce the sshd to fix it. i am working on the root cause still. IN between we observed that scp issued from another server to this server hangs intermittently(4 time this month), which uses the same ssh version.(no sshd hung occured during those time when we had hung scp).]

#ps -aex|grep scp

18715 ? 0:00 scp -p adedd80p:/opt/emc/maps/vgeb_rdo0_p_a_mgr.map /opt/emc/maps
18716 ? 0:00 /opt/ssh/bin/ssh -x -oForwardAgent no -oClearAllForwardings yes adedd80p scp -p -f /opt/emc/maps/vgeb_rdo0_p_a_mgr.map

10754 ? 0:00 scp -p adedd80p:/opt/emc/maps/vgeb_rdo0_p_a_bin.map /opt/emc/maps
10755 ? 0:00 /opt/ssh/bin/ssh -x -oForwardAgent no -oClearAllForwardings yes adedd80p scp -p -f /opt/emc/maps/vgeb_rdo0_p_a_bin.map

6612 ? 0:00 /opt/ssh/bin/ssh -x -oForwardAgent no -oClearAllForwardings yes adedd80p scp -p -f /opt/emc/maps/vgeb_rdo0_p_a_mgr.map
6611 ? 0:00 scp -p adedd80p:/opt/emc/maps/vgeb_rdo0_p_a_mgr.map /opt/emc/maps

3686 ? 0:00 scp -p adedd80p:/opt/emc/maps/vgeb_rdo0_p_a_arc.map /opt/emc/maps
3687 ? 0:00 /opt/ssh/bin/ssh -x -oForwardAgent no -oClearAllForwardings yes adedd80p scp -p -f /opt/emc/maps/vgeb_rdo0_p_a_arc.map


[/etc/opt/ssh]# grep -i Forward sshd_config
#AllowTcpForwarding yes
X11Forwarding yes


tusc just shows the process is sleeping

( Attached to process 6611 ("scp -p adedd80p:/opt/emc/maps/vgeb_rdo0_p_a_mgr.map /opt/emc/ma") [32-bit] )
1200346572.072329 [6611]{6935190} read(8, 0x6d3f04f0, 1) .............................................. [sleeping]

any hints/suggestions..

[Steven E. Protter]

Shalom,

See /var/adm/syslog/syslog.log

Check the system or event log on the target server.

It could be a network hang.

Also, it could be a problem with secure shell (open ssh) for HP-UX.

You might want to try a newer version because this software is updated with great frequency.

SEP

[skt_skt]

Infact in this case we are NOT able to read the syslog as we have enabled the debug7 logging for sshd and redirected to /dev/null for a troubleshooting purpose. The sshd debug log will be directed to a file(updating syslog.conf) only when the said sshd hang occurs...

We use the same ssh version across all servers..Only one server is giving trouble.

At this moment we suspect the "MaxStartups" [man sshd_config]..

[skt_skt]

it was a big with ssh version.. We are planning to update to version 04.70.009..

for 11.00 servers verison 04.30.014 would be used as this is the latest supported for 11.00