Re: DNS Records for an Exchange Server serving multiple domains

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From: Ace Fekay [MVP] (PleaseSubstituteMyActualFirstName&LastNameHere_at_hotmail.com)
Date: 07/09/04 

Date: Thu, 8 Jul 2004 22:16:44 -0400

In news:5chre01pud2od6es3vq6r20sla1ltd0rqv@4ax.com,
hal@nospam.com <hal@nospam.com> asked for help and I offered my suggestions
below:
> On Thu, 8 Jul 2004 17:16:37 -0400, "JP"
> <NO_SPAM_PLEASE_pangjo@netzero.com> wrote:
>
>> Sorry for crossing-posting. I really don't know which NG should I be
>> posting this question.
>>
>> We are currently running an Exchange server, which is serving the
>> users in the head office under domain-A. We have a few sales
>> offices which also have users who requires email access. They want
>> to use their own email domain (i.e. domain-B, domain-C and so forth)
>> due to the nature of our business. Therefore, we want the same
>> Exchange server to send and receive email for multiple domains.
>>
>> On the Exchange side, I can add other domain names in the ESM and
>> set up proxy email address under each user's account property. But I
>> do not know what would be the best practice on the DNS side. I am
>> thinking of requesting the ISP to add the MX records for domain-A,
>> domain-B and domain-C accordingly. They should all be pointing to
>> the same IP address as the one we use for domain-A.
>
> Yes, that is correct.
>
>> However, the technician from my ISP disagreed with
>> that. He said that it would upset reverse-DNS lookup if an IP
>> address is used by different domains.
>
> He is not correct. Reverse DNS does not matter.
>
> Hal

Hi, just wanted to add that I host 25 customer domains and I do it this way.
But my reverse points to the main machine's name and IP, not all the
customer domains, so this way if any recipient domains are performing
Reverse DNS lookups, it will come back as valid. So for the original poster,
don't worry about what the tech says, just let the reverse point to your
machine's actual FQDN.

I think the tech thinks you wanted a reverse for each one so there will be
multiple PTRs for the same IP, which won't work anyway, besides, I've tried
that in the beginning and found that MS DNS winds up removing all but the
one. There is no Round Robin for the reverse. 

-- 
Regards,
Ace
Please direct all replies ONLY to the Microsoft public newsgroups
so all can benefit.
This posting is provided "AS-IS" with no warranties or guarantees
and confers no rights.
Ace Fekay, MCSE 2000, MCSE+I, MCSA, MCT, MVP
Microsoft Windows MVP - Active Directory
HAM AND EGGS: A day's work for a chicken;
A lifetime commitment for a pig.
-- 
=================================

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