Hi Linux gurus, we are using centralized Sudoers file for all our RHEL servers, we have assigned lower cases for users in sudoers file. But on few servers users are created using both upper and lower case letters and on those servers the sudo doesn't workl for them, Is there way we can ignore the cases in sudoers file to avoid this kind of issue? Following is an example:

host01:/# id markt
uid=1008(MarkT) gid=1(staff) groups=2209(informix)

host01:/# grep markt /etc/sudoers
User_Alias UA_UNIXTEAM = root,kevinge,rtomines,markt,tammon,amohamme,adsharma

host01:/# sudo -l -U markt
User MarkT is not allowed to run sudo on txcomregappqa51.

I have not tested this, but, as Linux is case sensitive, I don't think so. The best course of action would be to educate your users, but I know that that can be a thankless task.

You may find something useful in this document (PDF) that describes how to use NAME_REGEX to enforce rules for user names. I can't test this, but I hope it helps.