pam_realm verifies if the user name follows the format user@realm, where realm is provided as input.
Thankfully, pam_realm provides users with a number of helpful options to customize the tool to fit their needs. For instance, the debug option doesn't actually do anything at present, but may be useful in future updates or for those working to understand the tool's programming.
Another great option is realm=realm, which allows you to specify the realm you want to check usernames against. This is particularly helpful since usernames vary from realm to realm and this option ensures your username check is tailored to your specific use case.
pam_realm also includes the allowbare option, which allows you to broaden the scope of your username check by including usernames without the "@realm" portion. Meanwhile, the nostrip option can be helpful for those who need to check the format of a username without removing the "@realm" portion.
As an example, you might use pam_realm in the following way:
auth requisite pam_realm.so realm=mail.example.com
auth require pam_unix.so.
Overall, pam_realm is a solid tool for any software developer in need of user name checking functionality.
Version 0.2: N/A