question firewall and bind

hi all, I used the app "macanalysis" to check a new configured mac os x 10.2.4 server. this app found 2 minor and this "major" security hole: Bind:53 is active (Risk: Very High) Resume: This server respond to an IQUERY and NXT request, this vulnerability can be exploited to gain root compromise. Fix: Restrict access to 53/tcp to local clients and nameservers. unfortunately I don't know how to close this potential security hole, so I would like to ask, if anybody has some advice for me - many thanks in advance! yours sincerely ferdinand