Re: [cobalt-users] How To: Automatically restart login services

[Gerald Young <me@xxxxxxxxxxx>]

Hello Joe.

Thanks for the script I have been playing locally (redhat 7 ) and it works a
treat. When we got hacked we lost cron and most of the controil panel except
the install software portion. So i think ill put up a cron version as well as
making a password protected web version that can be used to restart ssh or
telnet. 
Being locked out is no fun :(

Sys adminmag is on my reading list good stuff.
best wishes Gerald Y

On Sat,
28 Jul 2001, you wrote: > I have seen many posts about users who "are not able
to telnet or SSH" > into there cobalt's for many reasons.  I was reading an
article in Sys > Admin Magazine (www.sysadminmag.com (If you don't read it I
would > recommend it, very straight to the point with real world solutions)) by
> Hiu F. Ho (plug) that talked about automatically restarting login
> services on a remote host.  Below is a synopsis that does work on a RAQ3
> and should work on all other cobalt boxes, actually it should work on
> any Linux and *nix platform.  The standard disclaimer applies, Use at
> your own risk.  I will say that I am using this on my Cobalt, a bunch of
> Solaris and some Red Hat 7.0 servers.  
> 
> Step 1 - Find out the process name of you login daemon 
> 
> $ ps ax 
> 494 ?   s       0:02 /usr/sbin/shhd 
> 679 ?   s       0:05 /usr/local/psionic/portsentry/portsentry -atcp 
> 681 ?   s       0:00 /usr/local/psionic/portsentry/portsentry -audp 
> 
> This will list the processes that are currently running on your box.
> Look for the name that you are currently looking to automatically start.
> i.e. SSH or Telnet (please install SSH if you are still using Telnet).
> Write down the process name it will have to be entered into the perl
> script later. Also If you don't have the portsentry process running I
> would recommend installing it.
> 
> Step 2 - Specify the path to the login daemon 
> 
> $ which sshd 
> /usr/sbin/sshd 
> 
> This list the path to the Daemon that you are looking to restart
> automatically. White the output down this will also have to be entered
> into the perl script.
> 
> Step 3 - Copy the perl script to your box. 
> 
> #!/usr/bin/perl -w 
> #  This script was written by Hiu F. Ho and posted 
> #  to Cobalt users by Joe Seitzer (joe@xxxxxxxxxxxxxx) 
> 
> # The first line looks for your process 
> # name, output from step 1 
> # You may need to customize. 
> 
> $ps_entry = "/usr/sbin/sshd"; 
> 
> # The next line sets the path to the 
> # process you want to restart, 
> # output from step 2. 
> # May need to customize 
> 
> $sshd_path = "/usr/sbin/sshd";             
>   
> # There is nothing else that you need to edit. 
> # The next 8 lines will determine if the 
> # process you specified is running 
> @processes = `ps ax`; 
> $n = @processes; 
> $is_running = 0; 
> for ($i=0; $i<$n; $i++) { 
>   if ($processes[$i] =~ /$ps_entry/) { 
>     $is_running = 1; 
>   } 
> } 
> 
> # If the process you specified is not running 
> # the next 3 lines will start it 
> if (not $is_running) { 
>    `$sshd_path &`; 
> } 
> 
> 
> 
> Step 4 - chmod and chown so that it can only be read, written and run by
> root. 
> 
> $chmod 700 chk-sshd.pl 
> $chown root chk-sshd.pl 
> 
> Step 5 - Add a new cron job for root or append to one that already
> exists. Below is the line you want in the cron tab.  I have it set to
> check the sshd every 5 min, you can change this.
> 
> 0.5.10.15.20.25.30.35.40.45.50.55 * * * * /path to script/chk-sshd.pl 
> 
> after you have added the above line re-run crontab to check for errors. 
> 
> $ crontab -u root mycrontab 
> 
> You are done.  You should now have an almost fool proof login service.  
> 
> You can test this by killing the login service and logging back in 5 min
> latter. 
> 
> $ killall -9 sshd 
> 
> After 5 min you should be able to log back into you box.  Remember this
> is only good if your Login Daemon stops or is killed.  This will not
> help if you lose conductivity, hardware failure, software crash or have
> any other problems with your server. 
> 
> Enjoy:-) 
> 
> Joe Seitzer 
> www.pkicentral.net 
> 
> 
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