topic Re: Checking ssh authentication in a script in Operating System - HP-UX

Checking ssh authentication in a script

Tony Walker_2 — Fri, 03 Dec 2004 05:45:56 GMT

I'm writing a script which will ssh to our various machines and perform some automated tasks. There are some machines however that do not yet have key authentication set up and as such when I run the ssh command it asks for a password and waits. How can I check for and ignore this behaviour and move onto the next server?

Thanks,

Tony

Re: Checking ssh authentication in a script

Charlie Rubeor — Fri, 03 Dec 2004 14:07:19 GMT

I get around this issue by looking in the authorized_keys file. Before performing the ssh command, I execute the following:

grep root@ /.ssh/authorized_keys

That does not quarantee that the authorized key will be up to date, but it's the closest I could come up with. If you come across a better solution, please let me know!

Re: Checking ssh authentication in a script

RAC_1 — Fri, 03 Dec 2004 14:22:12 GMT

In this case you will need to use expect tool. What this tool does is lloks at "prompts" and keys in things that you want.

There docs about this tool and easy to to understand.

Anil

Re: Checking ssh authentication in a script

Sridhar Bhaskarla — Fri, 03 Dec 2004 22:42:14 GMT

Tony,

You could try forcing the options like this

ssh -o "PreferredAuthentications publickey" -o "StrictHostKeyChecking no" $i "your command"

-Sri

Re: Checking ssh authentication in a script

Florian Heigl (new acc) — Sat, 04 Dec 2004 05:03:07 GMT

Sridhar, this was *very* helpfull - I had always tried with passwordauthentication no, but without success.
Thanks a lot to You :)

Re: Checking ssh authentication in a script

Tony Walker_2 — Mon, 06 Dec 2004 03:16:10 GMT

Thankyou all. Sridhar - your suggestion worked perfectly.