Connection test : Net::SSH::Perl : $ssh->login

jxh has asked for the wisdom of the Perl Monks concerning the following question:

Using ActiveState Perl 5.8, Im looking to check some username/password combinations, via ssh connection.


my $ssh = Net::SSH::Perl->new("some_unixhost");

$ssh->login("user", "password");

my ( $out, $err ) = $ssh->cmd("exit");
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Try as I might, I cant figure how to check if my login was sucessful. ( I dont need to do anything further, just check ) In the case of a failure, the ssh->cmd causes an error, but I cant seem to handle this very neatly, I dont think this is the way. $ssh->login doesnt seem to return anything I can use. The 'new' method returns an object, can I do anything with this once Ive called a login ? Stuck.

Comment on Connection test : Net::SSH::Perl : $ssh->login - detecting failure Download Code

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Re: Connection test : Net::SSH::Perl : $ssh->login - detecting failure by u235sentinel (Hermit) on Feb 18, 2006 at 02:18 UTC
I dont think this is the way. $ssh->login doesnt seem to return anything I can use. The 'new' method returns an object, can I do anything with this once Ive called a login ? Stuck. Originally I used IO::SOCKET to check if port 22 was even there. But that didn't check if login worked or not. Since then I've been wrapping $ssh->new and $ssh->login inside eval which seemed to do the trick. I even logged which servers it failed on so I could check later on. You might want to give that a try. It seems to work pretty good.	[reply]
Re^2: Connection test : Net::SSH::Perl : $ssh->login - detecting failure by jxh (Acolyte) on Feb 18, 2006 at 12:03 UTC
Hi, thanks for the response - Ill give the eval a go and post back. My subtle difference between the two posts though : This one will test ssh using the 'key files' ( ie no password supplied ) whereas the Net:SSH::Perl question ( node_id=531107 ) I am using to check I have valid username / password combinations. ( Scenario : should my key files become regenerated / otherwise break - I need to know I can still use the password to log in an correct it ) I think I can apply your suggestion to both problems however.	[reply]
Re: Connection test : Net::SSH::Perl : $ssh->login - detecting failure by mojotoad (Monsignor) on Feb 19, 2006 at 07:52 UTC
I bumped into this issue a while back. While I'm not sure this is the "best" way, I too ended up relying on cmd() failure to figure out whether I was truly logged in or not. In my case the remote machines were all unix/linux based, so I'd issue a simple "uname -n" and see if I got back the same hostname as I was expecting. If the call to cmd() failed, I'd propagate the failure. If the call to cmd() succeeded but the hostname didn't match...well that was a whole other sort of error (which in my case never happens in practice...but it can't hurt to check). One thing I noticed with the various calls to Net::SSH::Perl is that there were two ways to fail...ungracefully, which would die/croak...and gracefully, which would return actual error codes and messages. So consider encapsulating the various calls to "things that might fail" within eval blocks. Then you can check $@ along with the various arguments that are returned via the calls to login(), cmd(), etc. Cheers, Matt P.S. I don't happen to have the code in front of me at the moment, but /msg me if you want to check out my 'cascading' failure with Net::SSH::Perl that pretty much guarantees a working connection or a meaningful error. I'll repost it on request (but don't feel like re-writing it on the fly).	[reply]
Re^2: Connection test : Net::SSH::Perl : $ssh->login - detecting failure by jxh (Acolyte) on Feb 21, 2006 at 19:53 UTC
Hi all, have wrapped in eval an it is now functioning satisfactorily. ( And I have learnt eval as Im still fairly new to this ! ) Case closed. Thanks again. NB - I now have a separate issue, getting error : Protocol error: expected packet type 20, got 93 at C:/Perl/site/lib/Net/SSH/Perl/Packet.pm line 221 when connecting. Can anyone give me any pointers ?	[reply]