Mailing List Archive

MSAs' role as a shield for recipient MTAs against garbage HELOs (was: HELLO macro and PTR)
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Arthur Kahlich wrote on spf-devel:
> Julian Mehnle wrote:
> > Stuart D. Gathman wrote:
> > > Unfortunately, way too many of my clients customers send their email
> > > with OEMCOMPUTER as the HELO name. Rejecting on invalid HELO in
> > > general is regrettably not an option at this late stage of RFC2821
> > > apostasy.
> >
> > That shouldn't be an issue. End-user software should never be allowed
> > to connect to recipient MTAs directly. Instead, they should be
> > channeled through a sender-side submission server (MSA) with
> > authentication. The MSA can then ignore any brain-dead input data and
> > override it when relaying the mail.
>
> I have been a lurker on [the spf-devel] list up until now, but I have a
> common use case that seems to contradict what Julian has said [above].
> Unless I am missing some subtlety here, whenever I send email to another
> user on my mail server my end-user software is connecting directly to my
> recipient MTA, using the same mechanism that a remote mail server would
> use to deliver mail to my mail server. The validation mechanism is
> different in that a login is required, but that is the only difference I
> know of. Since I administer a small organization I can enforce proper
> HELO names, but in general this is not true.

(This really belongs on spf-discuss, so please follow up there.)

Arthur, in your scenario, your internal MTA is dual-acting as the MSA,
given that your end-user software still authenticates with it when sending
mail to other users on that server. So my statement still holds.

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