On Wed, Jul 05, 2017 at 03:11:57PM -0400, Miles Fidelman wrote: > The language in RFC 5231 does not explicitly say that the HELO name > should be resolvable, but strongly implies it.
No, it does. Note that "domain" is given as the argument to EHLO, and see how "domain" is defined in 2.3.5. See also the discussion of EHLO in 2.3.5: " o The domain name given in the EHLO command MUST be either a primary host name (a domain name that resolves to an address RR) or, if the host has no name, an address literal, as described in Section 4.1.3 and discussed further in the EHLO discussion of Section 4.1.4." That's a MUST. Either resolve to an address or use an address literal. If we're RFC-lawyering, however, note that it does not explicitly require that the EHLO name resolves to the connecting client's address, just to "an address". And continuing, any site MAY have policies which are not set out specifically in RFC 5321 or other standards. So this whole discussion probably is pointless. :) -- http://rob0.nodns4.us/ Offlist GMX mail is seen only if "/dev/rob0" is in the Subject:
