Freegal Music Service requires that the last two lines of config.txt are:
SSO -Secret=somesecret -URL=http://www.freegalmusic.com/users/sso?libname=site freegalmusic
where somesecret and site are both provided to you by Freegal.
To access Freegal, you will need to construct a URL similar to:
replacing ezproxy.yourlib.org:2048 with your own EZproxy server hostname and port.
The IncludeIP directive forces all users to authenticate. If you omit this directive, browsers accessed by local users will go into a redirect loop.