dBpoweramp CD Ripper in particular uses a number of internet addresses in relation to metadata:

reg.dbpoweramp.com // to activate perfectmeta

accuraterip.com // accuraterip secure ripping results

dmr.allmusic.com // amg
gdwebservice.getdigitaldata.com // GD3 metadata
74.86.240.219 // Musicbrainz
freedb.org // freedb metadata