Re: Fixed but no idea why.

I put mail.windward.net as the FQDN because of posts in this NG saying
that was necessary so spam filters do not throw away messages as they
would be coming from a box that is not a MX record for us.

That was a pretty nonsensical suggestion. There is no requirement --
zip, nada -- that messages from your domain originate from a published
MX from your domain! The only time a similar restriction exists is
when _you_ deliberately publish a policy, using SPF for example, that
instructs those remote machines that check SPF records to reject mail
that does not originate from a specified collection of senders.

Furthermore, setting your mailserver, which is on a different IP with
(presumably) its own PTR entry or no PTR entry at all, to impersonate
another IP's canonical name is _more_ likely to cause rejections
because you fail the PTR/A roundtrip check. What you want is
simplicity and circularity. The mailserver IP's PTR --> the A record
for that PTR --> the IP your of your mailserver.

Our topology is that the IIS SMTP server box is outside our firewall
(going to a co-lo facility soon) while our exchange box is inside our
firewall. So they have distinct IP addresses.

Then they should also have distinct PTRs, and thus different FQDNs.

Do I not need to set the FQDN? Or is that necessary as the box has an
IP address that is not in our MX.

As above, being an MX is not a requirement to originate mail. Passing
a DNS roundtrip check _is_ a requirement.

--Sandy


.

Relevant Pages

  • Re: Fixed but no idea why.
    ... I set the FQDN to the name of the box it is on and it seems to be ... that does not originate from a specified collection of senders. ... its own PTR entry or no PTR entry at all, ... The mailserver IP's PTR --> the A record ...
    (microsoft.public.inetserver.iis.smtp_nntp)
  • Re: Need a hand deciphering this NDR
    ... the PTR lookup was initially done by www.dnsreport.com and both came ... Our mailserver, however, is not configured to do reverse lookups... ...
    (microsoft.public.exchange.setup)
Loading