Multiple reverse DNS records for a single Exchange server environment
Posted on 2010-09-06
One of our clients has multiple companies working out of the same building. All of these
companies, as far as the outside world should understand, are not part of a single entity.
They have a single Exchange 2007 server environment.
The problem we have is when company B sends a mail out, the header comes back with the details of Company A, as this is the reverse DNS setting. I understand this is how Reverse DNS works, it doesn’t matter what address you send out from, as long as there is a “valid” Reverse DNS record in place, then the mail will send out ok.
All email is sent through a Sophos ES1000 appliance, and this appliance is set as the smart host for the Exchange server and this appliance is only capable of handling a single FQDN.
The company has multiple IP addresses to use.
What I would like to seems simple.
I would like the ability to set up multiple connectors in Exchange 2007, each with a different FQDN, and each one with a different Reverse DNS record to a separate public facing IP.
I do understand that this will not be possible if all email is going out through the Sophos mail appliance, so for the purpose of this question, let us rule that out.
There is a Sonicwall NSA2400 in place, and the whole environment is ESX4.0 if this has a bearing on anything.
Do me a favour and don’t past me any links on how Reverse DNS works and how to configure you Reverse DNS record, I do understand this. This problem is I need multiple reverse DNS records.