FreeRADIUS Beginner's Guide

Time for action – using regular expressions

Unlang allows regular expression evaluations in condition checking. These usually are Posix regular expressions. The operators =~ and !~ are associated with regular expressions. For a simple proof of concept we will modify the previous exercise:

1. Edit the sites-available/default virtual server under the FreeRADIUS configuration directory and add the following inside the post-auth section, at the top of the section:

   if(request:Framed-Protocol =~ /.*PP$/i){
       update reply {
           Reply-Message := "Regexp match for %{0}"
       }
   }

2. Restart FreeRADIUS in debug mode and try to authenticate as alice. First add a 1 to the end of the radtest command, then omit the 1.

   Take note how the regular expression match changes the value ...