router installed, lost aol.com transferability

[crabby117]

A while back, we installed a cheapo Linksys router between our Exchange server and the outside world so that we could configure the Linksys to direct FTP traffic to an alternate box.

Exchange was/is configured to reach out to one aol account and deliver the mail to a specific mailbox. It can no longer do that. Also, all outbound email (from any user) to aol.com gets stuck in the queue and we get an SMTP protocol error. All other email is fine, in both directions.

We didn't do any special configuration to the router (i.e. block ports) other than redirect FTP traffic. Did we miss a configuration step or cause a problem by introducing the router's static IP between the Exchange's IP and the outside world? (The Exchange's external IP did not change.)

Thanks much.

 

[xmsre]

And, somehow that's a bad thing?

Seriously, somewhere out in realworld DNS is an MX record that points to the outside interface of the linksys. In addition you'll have an A record and a ptr record. Given the behavior, I bet the new router has a different IP. If there is no matching ptr record for the a record in outside real world DNS, AOL thinks you're a spammer. Call your ISP and make sure your DNS records are up to date.

 

[crabby117]

Thanks xmsre. I hear you about AOL; I've got no love for them personally.

After talking with the guy who installed the Linksys, he said the ISP's device was put into "bridge mode" (the ISP did this remotely themselves) and the linksys was given the IP that the ISP's device used to have. That being the case, there should be no effect on MX, A, or prt records, right?

 

[xmsre]

This means that, in external dns:

1. an A record exists for the Exchange IP
2. a ptr record exists for the Exchange IP
3. an MX record points to the Exchange IP

These records need to be changed to point to the linksys external IP (the IP of the ISP device). In addition to forwarding ftp to the ftp box, the linksys should forward port 25 to the exchange box.


AOL does a reverse lookup, and the records are mucked up.

It sound like you use the dreaded pop connector. External mail goes to the one pop account. Exchange initiates a connection and retrieves the mail (still works inbound). Outbound, everything goes directly from the exchange server over port 25.

 

[bkuepers]

From you post you're talking about outbound delivery. Reverse lookup could be your issue, but you should also look at outbound name resolution of aol.com.

There is an issue with the way windows 2003 servers do DNS. This can cause issues with some firewalls or querying other DNS servers.

On the internal DNS server(s) that your exchange server uses, type the following into the command line. This is of course assuming they are 2003 servers.

dnscmd /config /enableednsprobes 0

This fixed the exact same issue for me on lots of servers.

See KB832223 for details.

Good luck.