Summary

This chapter looked at authentication in FreeRADIUS. Specifically, we have covered:

• Authentication protocols: There are three popular authentication protocols, namely, PAP, CHAP, and MS-CHAP. PAP is the least secure in certain situations but also the most versatile.
• How FreeRADIUS handles Access-Requests: When an Access-Request reaches the FreeRADIUS server the authorize section defined in the virtual server determines which authentication method will be used. The value of Auth-Type indicates which authentication section will be used.
• Password storing: Passwords do not need to be stored in clear text and it is better to store them in a hashed format. There are, however, limitations to the kind of authentication protocols that can be used when the passwords are stored as a hash.

Now that we've learned more about authentication, especially about the storing of usernames and passwords in the users file, we're ready to connect to alternative sources of usernames and passwords...