Hi all, My issue got sorted on the bind mailing list. FYI, I needed a zone file like the following to get the query to work: localhost A 127.0.0.1 $ORIGIN 8.6.4.e164.arpa. 9 IN NAPTR 100 10 "u" "e2u+sip" "!^.*$!sip:4251@aastra.com!" . Cheers, Marc