Limiting SSH Access
Remote access are enabled by using SSH. Whilst this surely makes it more secure than telnet, there are times when you want to have finer-grained control over what SSH commands can be executed from remote. Right now, there is no built-in facility to accomplish this so a Perl-based script, authprogs, can do this for you. For a more detailed how-to, check out this article.
Image from Flickr:haynes.