How to know if I'm blacklisted

Glenn Steen glenn.steen at
Sat Jan 19 08:52:47 GMT 2008

On 18/01/2008, Matt Kettler <mkettler at> wrote:
> Glenn Steen wrote:
> >>
> >> So, using such validation to refuse mail is RFC non-compliant.
> >
> > The magic is in:
> > -----
> >              Note also that the HELO argument is still required to have
> >              valid <domain> syntax, since it will appear in a Received:
> >              line; otherwise, a 501 error is to be sent.
> > -----
> Fair enough, so you can deny it if it doesn't conform to the domain syntax.
> Note this doesn't mean it must be resolvable, or even be a valid domain, it just
> has to logically conform to the syntax requirements of a domain. "mail2.canal4"
> is valid domain syntax, even if it's not a valid domain.
> > ... which is a bit further down. Your quote below is in regard to
> > doing an MX lookup on the string.
> Or any DNS lookup. It would appear the only time you can refuse is if it's
> syntactically invalid.
Yes. Exactly. One such invalidity is to use an email address syntax
(... at ....), which an amazing amount of spam senders use that.
One can argue about what is deemed a valid domain name, from a
syntactical viewpoint.... For instance, a bare word (xxxxx) isn't
syntactically correct either. Fortunate that the RFCs are pretty clear
on that too:-)
Hm. Perhaps one shouldn't be talking about this in a public forum....
the B*stards might get a clue:-).

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

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