Note

PAM allows stacking of authentication mechanisms. It is also possible to pass information obtained within one PAM module through to the next module in the PAM stack. Please refer to the documentation for your particular system implementation for details regarding the specific capabilities of PAM in this environment. Some Linux implementations also provide the pam_stack.so module that allows all authentication to be configured in a single central file. The pam_stack.so method has some devoted followers on the basis that it allows for easier administration. As with all issues in life, though, every decision has trade-offs, so you may want to examine the PAM documentation for further helpful information.