select the wrong remote mail server

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dt1649651@yahoo.com - 30 Jul 2008 16:35 GMT

When I send emails to users at one particular domain, my exchange
server keep making smtp connections to the backup mail server of that
domain, instead of the primary. The remote backup mail server is an
old one so not all mailboxes exist, and I get the rejected email that
those users do not exist.

When I open a dos window and manually telnet to port 25 of the remote
primary mail server and manually send smtp command ehlo, mail from.
rcpt to, data .... then it works just fine.

Why my exchange server do not use the primary one ?

Any advice is greatly appreciated.

Thanks,

DT

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Mark Arnold [MVP] - 30 Jul 2008 16:47 GMT

>When I send emails to users at one particular domain, my exchange
>server keep making smtp connections to the backup mail server of that
[quoted text clipped - 13 lines]
>
>DT

There must be a connector that's telling Exchange to route mails to a
server that isn't there as a "bridgehead". Exchange doesn't route
something to a non existent place for the heck of it.

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Steven - 31 Jul 2008 01:47 GMT

This actually sounds like the MX record for this one particular domain
are setup so that the old server has a higher priority than the new one.
From your Exchange server, when you do an NSLOOKUP for the domain, does
the older server show having a higher MX preference? If so, that's
probably why.

-----Original Message-----
From: dt1649651@yahoo.com [mailto:dt1649651@yahoo.com]
Posted At: Wednesday, July 30, 2008 11:35 AM
Posted To: microsoft.public.exchange.admin
Conversation: select the wrong remote mail server
Subject: select the wrong remote mail server

When I send emails to users at one particular domain, my exchange
server keep making smtp connections to the backup mail server of that
domain, instead of the primary. The remote backup mail server is an
old one so not all mailboxes exist, and I get the rejected email that
those users do not exist.

When I open a dos window and manually telnet to port 25 of the remote
primary mail server and manually send smtp command ehlo, mail from.
rcpt to, data .... then it works just fine.

Why my exchange server do not use the primary one ?

Any advice is greatly appreciated.

Thanks,

DT

Reply to this Message

dt1649651@yahoo.com - 31 Jul 2008 21:36 GMT

> This actually sounds like the MX record for this one particular domain
> are setup so that the old server has a higher priority than the new one.
> From your Exchange server, when you do an NSLOOKUP for the domain, does
> the older server show having a higher MX preference? If so, that's
> probably why.

It was the first thing I checked. The backup server does have lower MX
preference.

I found out the problem: my server did contact the primary server in
the first place. This server refused the connection with my server
therefore my server tried the backup. I had a typo the ip address of
the primary server so I could not find it in the smtp log. The remote
primary server has a grey listing engine and it wants my server
sending a dns-resolvable greeting name in the EHLO command. After
changing the greeting name, everything works fine. The odd thing is
all other servers do not refuse the connection with my Exc server with
the non-dns-resolvable greeting name.

Thanks everybody.

DT

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