Unable to start sshd

[Chris Billson]

I've been following two guides to try and get an Ubuntu server to use MFA, SpanKey_QuickStart.pdf and OpenOTP_PAM.pdf

I managed to get it working on one server, but not another two, so i'm reasonably sure the WebADM server is in a good state.

The issue starts when i add the lines below to my /etc/ssh/sshd_config

AuthorizedKeysCommand /usr/libexec/spankey/authorized_keys

AuthorizedKeysCommandUser root

With these in, when i restart ssh, it fails to start, i get these logs.

/var/log/auth.log

Aug  4 16:07:24 SERVER sshd[1266]: Received signal 15; terminating.

ssh stop/waiting

ssh start/pre-start, process 5119

/var/log/syslog

Aug  4 16:07:24 SERVER kernel: [  539.088638] init: ssh main process (5109) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.088660] init: ssh main process ended, respawning

Aug  4 16:07:24 SERVER kernel: [  539.094238] init: ssh main process (5112) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.094256] init: ssh main process ended, respawning

Aug  4 16:07:24 SERVER kernel: [  539.100063] init: ssh main process (5115) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.100082] init: ssh main process ended, respawning

Aug  4 16:07:24 SERVER kernel: [  539.105757] init: ssh main process (5118) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.105775] init: ssh main process ended, respawning

Aug  4 16:07:24 SERVER kernel: [  539.112946] init: ssh main process (5121) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.112964] init: ssh main process ended, respawning

Aug  4 16:07:24 SERVER kernel: [  539.119944] init: ssh main process (5124) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.119963] init: ssh main process ended, respawning

Aug  4 16:07:24 SERVER kernel: [  539.125416] init: ssh main process (5127) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.125434] init: ssh main process ended, respawning

Aug  4 16:07:24 SERVER kernel: [  539.130787] init: ssh main process (5130) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.130805] init: ssh main process ended, respawning

Aug  4 16:07:24 SERVER kernel: [  539.136120] init: ssh main process (5133) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.136138] init: ssh main process ended, respawning

Aug  4 16:07:24 SERVER kernel: [  539.141443] init: ssh main process (5136) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.141488] init: ssh main process ended, respawning

Aug  4 16:07:24 SERVER kernel: [  539.146882] init: ssh main process (5139) terminated with status 255

Aug  4 16:07:24 SERVER kernel: [  539.146910] init: ssh respawning too fast, stopped

When i remark out the lines above, and restart, it starts ok.

I've checked files between the two machines, and they're all the same.

/etc/spankey/spankey.conf

/etc/openotp/openotp.conf

/etc/pam.d/sshd

/etc/ssh/sshd_config

/etc/nsswitch.conf

/etc/pam.d/common-account

/etc/pam.d/common-auth

also, if i use the test command "getent passwd" - i'm able to see it retrieve user names from the WebADM server.

Is anybody able to give me any pointers on how i can troubleshoot this further, or anything i may have missed?

Thanks

Chris

[Benedetto Lo Giudice]

Chris,

could you please try to start sshd manually, just to make sure that sshd is not printing any error which is not caught by syslog?

/usr/sbin/sshd -Ddp 10999

this starts sshd in foreground, in debug mode on a non-standard port.

Ctrl-C to kill it.

Maybe there is a typo in the sshd_config file?

Thanks for using our products!
Kind regards
Benedetto

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Kind regards
benedetto

[Chris Billson]

Thanks for your quick reply, its appreciated. 

I wasn't aware of the debug option, so thanks for that, it gave me some more output, but not anything i didnt already think i knew.

/etc/ssh/sshd_config: line 34: Bad configuration option: AuthorizedKeysCommand

/etc/ssh/sshd_config: line 35: Bad configuration option: AuthorizedKeysCommandUser

/etc/ssh/sshd_config: terminating, 2 bad configuration options

 although both boxes are the same version of Ubuntu, are these commands sshd version sensitive?

[francois...@rcdevs.com]

Hi Chris 

Which is your version of Ubutnu and sshd ?