April 2004
Intermediate to advanced
320 pages
9h 10m
English
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Control Login Access with PAM
Seize fine-grained control of when and where your users can access your system.
In traditional Unix authentication there is not much granularity available in limiting a user’s ability to log in. For example, how would you limit the hosts that users can come from when logging into your servers? Your first thought might be to set up TCP wrappers or possibly firewall rules [Hack #33] and [Hack #34] . But what if you wanted to allow some users to log in from a specific host, but disallow others from logging in from it? Or what if you wanted to prevent some users from logging in at certain times of the day because of daily maintenance, but allow others (i.e., administrators) to log in at any time they wish? To get this working with every service that might be running on your system, you would traditionally have to patch each of them to support this new functionality. This is where PAM enters the picture.
PAM, or pluggable authentication modules, allows for just this sort of functionality (and more) without the need to patch all of your services. PAM has been available for quite some time under Linux, FreeBSD, and Solaris, and is now a standard component of the traditional authentication facilities on these platforms. Many services that need to use some sort of authentication now support PAM.
Modules are configured for services in a stack, with the authentication process proceeding from top to bottom as the access checks complete successfully. You can ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.