A CDDB (Compact Disc DataBase) server can be queried by applications like CD rippers and CD players to obtain artist, album, track listing and other information about a given CD.
CD applications used to use CDDB servers such as freedb.freedb.org and freedb.musicbrainz.org. However, these servers have shut down in 2020.
Thankfully, the server at GNUDB continues to serve out CDDB info and is updated by users with info about new CDs.
To use the GNUDB server with my CDex ripper application, I had to use these settings:
gnudb.gnudb.orggnudb.gnudb.orgHTTP80/~cddb/cddb.cgiyour@email.com