You're right. Slackware doesn't. They're notable for that, and I don't think any other mainstream distribution (if Slackware even counts as that) excludes it.

You're right. Slackware doesn't. They're notable for that, and I don't think any other mainstream distribution (if Slackware even counts as that) excludes it. At least in the multi-user environments I manage, PAM works well, and we maintain some custom PAM modules to do things like handle unpaid accounts with warnings then lockout. It's a little complex but I don't know of any viable alternative -- setting up Kerberos on Slackware is a big pain last I checked. Maybe not relevant to single user machines, but that's not the context we're talking about here.