Removing MX Records from internal DNS

Singnetsvc
Singnetsvc used Ask the Experts™
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I want to find out that if I were to remove my MX records from my internal DNS would this have an adverse affect on my e-mail sending and receiving via Outlook/Exchange. I do not look after my own MX records for the outside world this is done by my ISP and as far as I am aware I have no need for them internally
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Commented:
You shouldn't have any MX records on your internal DNS.

If you are using your internal DNS and exposing it to the Internet as the authoritative DNS zone then you might want to think about fixing that.

If you're not doing it then you don't need MX records internally. Exchange does a GC lookup to see where the recipients mailboxes are and then DNS to send the email to the that right box.
Dont remove MX record from your Internal DNS...it is required for mail delivery

How many exchange servers do you have in your environment
Singnetsvc: Please ignore my comment...

czcdct: if we have mutiple servers in different sites do we need MX record or just GC lookup is enough..
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Commented:
Mohdabsar,

An Exchange server organisation does not use any MX records. If you had other domains, sub domains or whatever else that were connected then you could use connectors. If you didn't want to do that then you could indeed use MX records to receive mail from an Exchange organisation to (say) a Unix based solution, Notes environment or a different Exchange organisation in a different forest that was connected to your network.

Commented:
<quote>
Singnetsvc: Please ignore my comment...

czcdct: if we have mutiple servers in different sites do we need MX record or just GC lookup is enough..

You do not need any MX records in your AD Forest. If a user on mail server A wants to send a message to user123 the Exchange will do an AD lookup to find the homemdb attribute of user123. Exchange will then send the email direct to that server unless a routing and bridgehead topology is in place, in which case the email will go to that server via the routes it needs. At no stage are MX records involved.
czcdct: Thanks a million for Clarification
Donnie4572IT Manager
Commented:
Obviously, someone has inadvertently added mx records to your active directory dns. You should remove them. Internal mail flow does not use mx (mail server records)

The only time that your exchange server uses a MX record is to connect to a remote mail server for mail delivery. You exchange server contacts the public dns server that is responsible for that remote domain to obtain those MX records and not your internal dns.

Donnie4572IT Manager

Commented:
No MX record is needed to route mail between exchange servers that are in the same exchange organization/active directory forest.

However, MX records will be needed to route mail between two active directory forest.
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Commented:
The only reason I can think of to have MX records in the internal domain is if you have another SMTP server that uses the AD DNS, but is NOT an Exchange server and sends email directly.

Simon.

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