How to know if I'm blacklisted

[Glenn Steen]

On 18/01/2008, Matt Kettler <mkettler at evi-inc.com> wrote:
> Matt Kettler wrote:
> > Glenn Steen wrote:
> >> On 16/01/2008, Matt Kettler <mkettler at evi-inc.com> wrote:
> >> (snip)
> >>> The other part is your HELO is mail2.CANAL4. That really should be a
> >>> valid
> >>> hostname. It's technically not against the RFC's to spew garbage
> >>> here, but it
> >>> does show poor server administration, and some misguided sites seem
> >>> to think
> >>> HELO must be a valid hostname and filter such things (the RFC's
> >>> merely say
> >>> SHOULD, not MUST). You might want to fix the hostname your mailserver
> >>> thinks of
> >>> itself as.
> >>>
> >> Um, not misguided as in "that could be anything". At least 2821 is
> >> pretty clear that the argument to EHLO (use of which is only a SHOULD
> >> in conjunction with the stipulation that "if you don't use EHLO you
> >> MUST use HELO", more or less) need be a FQDN, unless you are operating
> >> in a situation where such isn't valid (no valid reverse lookup or
> >> dynamic allocation of IP etc), in which case it "should" be an address
> >> literal... So rejecting on an invalid domain (or address literal)
> >> SHOULD be quite OK;-).
> >
> > True, but if a system is using HELO instead of EHLO, anything goes.
> > There's no MUST in the requirements for HELO, merely SHOULD.
> >
> > ie: it is 100% in RFC spec to issue:
> >
> > HELO somerandomgarbage
> >
> > Although it is not in-spec to do that for EHLO, as you point out.
> >
>
> Note: I retract this based on RFC 1123, however, RFC 1123 does prohibit refusing
> mail based on HELO verifications.
>
On the contrary, if the domain name is malformed ... the return is
501;-). Look at the DISCUSSION, the second paragraph starting
"Note...".

The blurb about not rejecting based on verification is in regard to
(IP) address verification ... You're not prohibited to do an MX lookup
on the HELO string, but you're not allowed to reject based on that.

Cheers
-- 
-- Glenn
email: glenn < dot > steen < at > gmail < dot > com
work: glenn < dot > steen < at > ap1 < dot > se