SSH Hangs - Errors

[T. Rectenwald]

I have a server running 11.23 with SSH installed (A.04.30.007 HP-UX Secure Shell). The sshd daemon is continually hanging. A restart will correct this, but then it'll hang again. This seems to be triggered by SFTP processes coming into the server. The messages I get in the syslog.log are below:

Mar 19 10:08:16 sshserver sshd[1781]: Accepted publickey for user1 from 10.20.30.40 port 4165 ssh2
Mar 19 10:08:17 sshserver sshd[1781]: subsystem request for sftp
Mar 19 10:08:17 sshserver sshd[1781]: Pam Creds are not available
Mar 19 10:08:22 sshserver sshd[1781]: Received disconnect from 10.20.30.40: 11: Internal error.
Mar 19 10:08:22 sshserver sshd[1781]: pam_setcred: error Permission denied
Mar 19 10:11:42 sshserver sshd[8947]: Accepted publickey for user2 from 10.20.30.50 port 61817 ssh2
Mar 19 10:11:43 sshserver sshd[8951]: Debug level set to ffffffff.
Mar 19 10:11:43 sshserver sshd[8951]: pam_acct_mgmt: error Permission denied

The PAM messages seem to occur normally, but I'm not sure what the 11: Internal Error or "Debug level set to ffffffff" indicates, or how an SFTP process can put SSHD in a stable state. Has anyone seen something like this?

Best Regards,
Tom

[Michael Steele_2 · Accepted solution]

a) "Debug level set to ffffff". No I haven't. But here's a link describing how to set debug log levels in HP-UX sshd.

http://docs.hp.com/en/5991-7493/ch07s05.html

b) So you are on the right track setting ssh debug to be enable. Now refer to /var/adm/messages unless you're redirecting this data into /var/adm/syslog/syslog.log. Check /etc/syslog.conf for this.

Also refer to the sshd.log file which should be under /var/adm/syslog/sshd.log.

More data for you:

http://docs.hp.com/en/5991-7493/ch07s05.html

[T. Rectenwald]

Michael,

Thank you for the assistance with this. After placing SSHD in debug mode and doing some more research, it appears that there are SFTP jobs hitting the server that run simultaneously, rather than sequentially. I.e. someone runs this in bulk in the background. I changed MaxStartups in sshd_config from 10 to 20 and the hangs have stopped. So, that looks like the root cause. Thanks for pointing me in the right direction!

Regards,
Tom