I've read in many places that it's a good idea to tighten security by disallowing the root login using SSH and simply login via SSH as an unprivlidged user and then su to become root to perform actions that can only be done using the root login.

I have disabled root logins by (first) changing the /etc/passwd file to /sbin/nologin for the root account and (second) went into sshd.conf and turned off root logins.

I'm currently using Putty for all my SSH activity, and I've been logging in as an unprivlidged user and then su to become root. When I do this, if I try keying in "service smb start" or "service qmail stop", it returns an error... something like "unknown command". The only way I can start and stop services this way is if I login as root. When I do this, I can do everything I need.

It's almost acting like I'm not getting all of the root privlidges when I su root. How can this be? What settings do I need to change to make root have all the needed privlidges?

in order to get a full root shell (i.e. with all your environment variables, path, etc. set) use "su -" instead of "su"

actualy you are getting the root previliages but you just dont get the path variables so to run or stop services use /sbin/service sbin is the directory where system specific command lives.

Ok, I see now. Thanks for the help!