Adding AAAA records for existing nameservers will NOT cause TC to be set where it would not be set without AAAA records unless you do a "ANY" lookup of the nameserver where it MAY result in TC being set. All current implementations, including named, fail to set TC when adding glue records to a referral in contradiction on RFC 1034. This issue has been raised with the IETF dnsext wg. Fixing this would result in most COM/NET referrals, from the root, setting TC. Note: recent version of named will add glue which matches the question section is added to a referral in preference to other glue and if that glue rrset won't fit it then named will set TC to prevent the resolution process getting wedged. Usually only EDNS/512 + DO=1 queries result in a referral which fits the critera to set TC even then most such queries don't. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org