I will say from the beginnning that I am a beginner when speaking about pam. I have a system which was thowing errors in /var/log/secure like these:


crond[27099]: pam_tally(crond:account): unknown option: no_magic_root


So I was advised by soemone (who absolutely swore he new what he was doing) to copy the /etc/pam.d/system-auth-ac file from another system to clear these errors.

I did what he suggested now I am locked out of the box. Can not log in as root from console, and I can not get to single user mode by editing the line in grub.

Anyone have any ideas to help??

You can download disk 1 of CentOS from www.centos.org.

Let the machine boot from the disk.

Type linux rescue to boot the machine in rescue mode.

Choose the option to allow access to the hard drive

If you had made a copy of your original configuration file, you can use it to replace the one that is causing the problem.

If you didn't make a copy, you can backup the existing file and then edit it.

You should be able to do something similar with a live cd from Ubuntu.

The ability to boot from cd's is the main reason why security documents always recommend limiting physical access to your servers. It really doesn't matter which operating system you use.

It is very important to copy configuration files to a safe place before editing or replacing them.

1 members found this post helpful.

Thanks so much, I did make a backup of the file in the same directory.

I have copies of the redhat install CD's can I also boot with those?

CentOS is a clone of Red Hat. You can boot from the Red Hat cd 1.

Let us know how it turns out.

Thats for the help, everything worked out great!

Learn something new everyday! I really appreciate your assistance.

Cool... No problem...

It must be scary when you can't log into your server.

Please mark the thread as solved. It might help someone else.