>As an aside, I don't believe there's anything that prevents use >of TXT records, as currently specced, with wildcards, other than >lack of support in the more widely used nameservers.
It depends on what your plan for using TXT records is. If you're planning to use a prefix like _ssp.example.com, internal wild cards like _ssp.*.example.com aren't ever likely to work because it would be a compatibility issue. (Think of the fun when a secondary that doesn't handle them AXFRs a zone.) There's been some suggestions for internal wild cards marked by ** but I gather that has unpleasant interactions with DNSSEC. The alternative is to do what SPF did, put the TXT record directly at the name and use version strings at the beginning of each record to tell them apart. Beyond the gross ugliness, there's concerns about how likely client code is to reliably ignore the records it doesn't understand, and there may also be some issues where the names you want to wildcard for SSP overlap with the ones for SPF. We've gone around this enough times that I think that if there were a reasonable way to do wildcards with TXT records, we'd have stumbled across it by now. R's, John _______________________________________________ NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html