Re: SMTP Reverse DNS incoming option and external Email

From: Mike (anonymous_at_discussions.microsoft.com)
Date: 02/17/04 

Date: Tue, 17 Feb 2004 06:23:53 -0800

Hi Patrick,
   Thanks for your reply. That would be strange but would
it not stop their mail from coming internal as opposed to
stopping our mail from reaching them?
   Keep the thoughts coming though :)
   Mike

>-----Original Message-----
>Hi Mike,
>
>With that option "on" we only do a reverse lookup with no
other action. The
>only thing I can think of is that the other domain does
not allow reverse
>lookups of their domain. Even that would be strange....
>
>--
>Patrick Genova
>Pgenova@online.microsoft.com
>Please do not send mail directly to this alias. This
alias is for Newsgroup
>purposes only.
>This posting is provided "AS IS" with no warranties, and
confers no rights.
>
>"Mike" <anonymous@discussions.microsoft.com> wrote in
message
>news:11b6401c3f508$9773fb90$a501280a@phx.gbl...
>> Hi,
>> We have a very strange issue. We are using Exchange
>> 2000, we recently were approached by a user who was
>> unable to send Email to an external vendor Email
address.
>> The user was able to receive Email from the vendors
>> address but unable to reply. Long story short, here is
>> kind of a lowdown on what we did. Firstly I verified all
>> internal DNS and Exchange settings. After everything
>> appeared to be correct, I approached our ISP. They found
>> that the reverse DNS was missing for our Exchange
server,
>> it was added. The problem was still evident. I found
that
>> the FQDN was pointing to the servername as opposed to
the
>> MX alias. I changed it, no go. We troubleshot DNS, spam
>> rules, telnet, blacklists all to no avail.
>> We finally found the problem to be that the SMTP
>> virtual server on our Exchange server was performing
>> reverse DNS lookups on incoming Email. For some reason
>> this was not allowing us to send Email to this 1 domain.
>> No other problems with any other domains. I find it odd
>> that the incoming reverse DNS option would even have any
>> affect on outgoing SMTP mail.
>> Has anyone else seen this problem? Our ISP actually
>> found they had the problem also. This seems like a bug
in
>> EX2K if you ask me?
>> Thanks for any insight!
>> Mike <><
>
>
>.
>

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