Exchange Server - Edge server causing mail loop

Asked By Jeff Petschow

20-Nov-09 11:39 AM

I am trying to setup my edge servers. Outgoing mail works fine. When I enable
incoming mail to the edge server I get a DNS mail loop and the mail bounces
back to the sender. I have the accepted domains configured. When I run
Test-Edgesynchronization everything shows as synched.



Our current setup is incoming mail going to a smart host which sends it to
an Exchange 2003 server. I have moved all the mailboxes off the 2003 server
over to the 2007 server. Now all I need to do is get the incoming mail
moved. I change the DNS MX record that points to the smart host and point it
to the edge server. This starts giving me the DNS mail loop.



If I telnet to the edge server and send a mail message to an internal user
the route it takes is from the edge to the old smart host and then over to
the Exchange 2003 server and then the Exchange 2007 hub. Why would the edge
server not send it straight to the hub.



Thanks for any insight into this.



Jeff Petschow

College of DuPage

20-Nov-09 12:55 PM

On the Edge server use NSLOOKUP to be sure that the hosts where you are
pointing things are going to the right place.  Although it is hard to
diagnose your problem with scant information, I suspect that your Edge
server is getting confused between hostnames on the Internet and your
internal network.
--
Ed Crowley MVP
.

20-Nov-09 02:35 PM

Sorry Ed, I am not sure what you mean by the hosts where you are pointing
things are going to the right place. On the edge is there isomething I set to
send it to the hub? On the send connector for inbound to
default-first-site-name on the Network tab I have it set to use DNS MX
records to route mail. Is this the correct setting? It seem that this looks
up the MX record for out domain and tries to route back to itself.

Jeff

20-Nov-09 03:46 PM

The Edge likely will not be looking at MX records.  What I am suspicious about
is the way DNS is configured on Edge might be causing it to route mail to
itself, for example.
--
Ed Crowley MVP
.

20-Nov-09 04:17 PM

I have the edge using are main DNS servers. I think you are correct in that
it is routing back to itself. How should the DNS be configured? Should I
select on the Send Connector to use External DNS settings on the transport
server?

Jeff

20-Nov-09 10:04 PM

Define "main DNS servers".  Follow the path.  Deterine what host it thinks
it should be sending mail, and use NSLOOKUP to see what IP address you get
for that host.
--
Ed Crowley MVP
.

23-Nov-09 04:06 PM

I can do an nslookup of the hub server from the edge server.
The edge servers are using our 2 internal DNS servers. The edge servers are
inside of the firewall. We do not use a DMZ. All exchange servers are on the
internal network and each server can resolve the name of the other servers.