PAMs are used primarily to regulate access to administrative tools and commands. It works as an additional layer of security for users. A substantial number of services and systems are PAM-aware. In other words, with the right modules, access to those services and systems can be regulated by rules defined in PAM configuration files in the /etc/pam.d/ directory.
To review available PAM modules for your distribution, search the applicable archives. On a Red Hat–based system, you can search with the yum search pam command. On an Ubuntu system, you can search with the apt-cache search libpam command. Just the titles in the output shown in Figure 4-4 provide a feel for the full capabilities of PAM.
FIGURE 4-4
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