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Re: [PLUG] Odd email problem
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Is there a middle hop in here somewhere? Is something looking up the
fqdn and relaying the message after substituting the hostname?
I hate to be 'that guy' but 3.6.2 of rfc 1034 seems to suggest that mx
records shouldn't be cnames.
Section 10.3 of RFC 2181 goes a little further and has this to say:
10.3. MX and NS records
The domain name used as the value of a NS resource record, or part of
the value of a MX resource record must not be an alias. Not only is
the specification clear on this point, but using an alias in either of
these positions neither works as well as might be hoped, nor well
fulfills the ambition that may have led to this approach. This domain
name must have as its value one or more address records. Currently
those will be A records, however in the future other record types
giving addressing information may be acceptable. It can also have
other RRs, but never a CNAME RR.
Now, the reason I asked if there was another hop on the way was
because obviously something is looking up the fqdn of the host. If the
hostname weren't a cname you wouldn't be seeing the 3 card monty with
the hostname.
That all said, the setup you're describing isn't exactly extra
ordinary. It usually works just fine, i wish I could point you at a
direct cause.
On Fri, Sep 26, 2008 at 1:10 AM, JP Vossen <jp@jpsdomain.org> wrote:
> I'm trying to diagnose an odd email problem with a GNU Mailman list.
> One list member is using Outlook to send email to the correct address,
> PANTUGGeneral@lists.pantug.org, but each message is being rejected as
> destined for PANTUGGeneral@mail.pantug.org. Note the @lists. vs. @mail.
> parts.
>
> We've gone so far as to sniff the outgoing traffic, but as far as I can
> tell it looks like normal SMTP leaving the local machine on the wire and
> going to the correct address. But Postfix logs a reject to the wrong
> address.
>
> For this, and other reasons he's switched hosting providers, and the
> problem persists. We're not aware of any SMTP proxies, and find it hard
> to believe that a proxy would swap parts of an address... OTOH, the
> reverse lookup of the server *is* mail. (not list.), so it's possible
> something is trying to be "helpful." We just can't figure out what.
>
> We've hacked around the problem by creating a local account and the
> necessary .forward file (/etc/aliases didn't work for mail domain
> reasons), but it's still really bugging me.
>
> Does anyone have any idea how this could happen, or suggestions on where
> else to look?
>
> Thanks,
> JP
> ----------------------------|:::======|-------------------------------
> JP Vossen, CISSP |:::======| jp{at}jpsdomain{dot}org
> My Account, My Opinions |=========| http://www.jpsdomain.org/
> ----------------------------|=========|-------------------------------
> "Microsoft Tax" = the additional hardware & yearly fees for the add-on
> software required to protect Windows from its own poorly designed and
> implemented self, while the overhead incidentally flattens Moore's Law.
> ___________________________________________________________________________
> Philadelphia Linux Users Group -- http://www.phillylinux.org
> Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
> General Discussion -- http://lists.phillylinux.org/mailman/listinfo/plug
>
--
J.
___________________________________________________________________________
Philadelphia Linux Users Group -- http://www.phillylinux.org
Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
General Discussion -- http://lists.phillylinux.org/mailman/listinfo/plug
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