The wording of your original post was a bit confusing to me. I understand
what you were saying now. Thanks for clarifying.
And to clarify how MX lookup works, when you have multiple MX records for a
domain, although the cost of the record plays a major factor, just because
you have one MX with a cost of 10 and another with a cost of 20 doesn't mean
that the one with the cost of 10 will guaranteed receive 100% of e-mail
destined for your domain. The MX with the cost of 20 will almost assuredly
be receiving queries.
The only advice that can be given at this point is to make sure that every
single MX record that is listed for your domain (whether that be your server
or your ISP's) has a valid PTR record that matches the A record.
Gardner & White
Exchange FAQ's: http://www.swinc.com/resource/exch_faq.htm
Exchange 2000 FAQ's: http://www.swinc.com/resource/e2kfaq.htm
> Hey Ben,
> Disagree with you. The MX record is looked up during resolution of the
> destination mail address.
> And in case you misunderstood me, I am pointing out the situation from the
> domains that Terry is trying to send to, not from Terry's perspective.
> > Doesn't work that way. MX Records deal ONLY with receiving mail, not
> > sending.
> > --
> > Ben Winzenz
> > Network Engineer
> > Gardner & White
> > Exchange FAQ's: http://www.swinc.com/resource/exch_faq.htm
> > Exchange 2000 FAQ's: http://www.swinc.com/resource/e2kfaq.htm
> > > Hi Terry,
> > > Dunno if this applies to your situation:
> > > We have a secondary MX record for our domain at the office which is a
> > > server with our ISP. Here I have not enabled the reverse lookup - too
> > > genuine mails dropped. However our ISP has to enable it on their side.
> > > Thus: if your sending domain does not resolve to the originating IP
> > address
> > > and you pick up a connection on the primary MX, your mail will be
> > accepted.
> > > If you get a connection onto the secondary MX, then it will be
> > > I hope this sheds a bit more light!
> > > Mark
> > > > Once in a great while we have an issue with sending to certain
> > > > This rarely happens and it always seems to be the same few domains.
> > > > this reason I tend to think it is an issue with the foreign host.
> > > > When a user sends to this particular recipient they get an NDR that
> > > states:
> > > > You do not have permission to send to this recipient. For
> > > > contact your system administrator.
> > > name
> > > > possibly forged [<ip address>]>
> > > > We looked at the SMTP logs and it would appear as though it queries
> > > > wrong MX host. The user can try to send the message again a few
> > > > later, the correct MX record is found and it sends just fine.
> > > > Any advice would be appreciated!
> > > > Terry