> 20741, so direct SPF RR hits is about one third of those using TXT RR, > small, but, insignificant? I wouldn't really say so, but some might. I > suspect the SPF wanting to be deprecated is because of the lack of > take-up, due to lazy admins, there are some resolvers in use from > ancient debian boxes that are so old, they dont understand the SPF RR, > yes I know, they have bigger problems than that, but, again, comes down > to laziness, DNS is not rocket science, I'm sure given ARM and access to > google, a 13yo kid could get at least the "basics" right.
Laziness?--nonsense. Postel's Law and simple logic predict the deprecating of the SPF type as well as the continued practice of publishing only TXT records by those with rational reasons to publish SPF data. 1. SMTP servers (mail receivers) that have wanted to honor SPF -all been forced to look for for SPF data in TXT records since the beginning. There have been far more TXT records with SPF data than SPF records. Therefore, the best course for SMTP servers has been to request TXT and only request SPF if the TXT request gives NODATA. Requesting both SPF and TXT types would cost extra bandwidth and raise questions about what to do if both are present and differ. Occassional differences between SPF and TXT are inevitable due to caching in recursive resolvers even when the authoritative server always changes both simultaneously. 2. Rational operators of SMTP clients (mail senders) know that well maintained SMTP servers understand #1 and so request TXT first or request neither SPF nor TXT. Publishing only SPF type records would double an SMTP client's DNS costs. Pubishing both SPF and TXT would not help well mantained SMTP servers, but cost maintenance complexity and so potential errors. Therefore, it is best to publish only TXT for well maintained SMTP servers. Badly maintained SMTP servers are likely to only check TXT records. Unlike the situations with IPv6 and DNSSEC, there are only costs and no benefits for rational operators SMTP clients or servers to change those two tactics. Those interested in wider perspectives about SPF and TXT RRs than any single domain or the perceptions of SPF enthusiasts might consider the tables reporting surveys in RFC 6686. One can ignore everything specifically about SenderID and read only about popularity of SPF and TXT records. https://www.rfc-editor.org/rfc/rfc6686.txt Vernon Schryver v...@rhyolite.com _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users