Masataka Ohta <mo...@necom830.hpcl.titech.ac.jp> wrote: > > > See RFC 1123 section 5.2.2. This requirement was dropped in RFC 2821 and > > successors. > > Perhaps, it is a misunderstanding of a suggestion of rfc974: > > Note that the algorithm to delete irrelevant RRs breaks if LOCAL has > a alias and the alias is listed in the MX records for REMOTE. (E.g. > REMOTE has an MX of ALIAS, where ALIAS has a CNAME of LOCAL). This > can be avoided if aliases are never used in the data section of MX > RRs.
No, that's about MX pointing at CNAME, which is frowned on but generally works. The fix for the problem mentioned in the quote above is to resolve MX targets all the way to IP addresses before discarding ones after the current host, instead of relying on host names only. CNAME pointing at MX is a different problem, which does not work consistently in practice. The requirement in RFC 1123 is a restatement of RFC 821 section 3.7 (last paragraph) and page 30 (penultimte paragraph). Tony. -- f.anthony.n.finch <d...@dotat.at> http://dotat.at/ Fair Isle: Northerly 6 to gale 8, but 5 at first in east. Moderate at first in southeast, otherwise rough or very rough. Rain or showers. Good, occasionally poor. _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
