[RFCI-Discuss] about FQDN for our smtp servers

[Alan Brown]

On Tue, 11 Apr 2006, Derek J. Balling wrote:

> >>  some MTAs will reject you you if
> >> your helo doesn't resolve.
> >
> > So is this.(*)
>
> No, this is not a RFC violation.
>
> By definition the argument must be a FQDN.  An FQDN is defined as
> something resolvable, I forget the specific location where it is so
> defined. Thus, if you HELO with something that isn't resolvable, it
> isn't an FQDN, and therefore you have not HELO'ed in a syntactically
> valid manner.

The RFC has a MUST NOT clause associated with non-resolving HELO
entries, which makes this claim arguable.

AB