Internal DNS vs External DNS

Hello everybody,

I have  a questions regard the internal and external DNS form exchange server 2010.

My internal DNS is the same as my external dns. Is there any problem for using the same name (internal) (external). If there is a problem what should I do?

I'm configuring exchange server 2010. Other question is: Is there any problem to install exchange on Domain controller?

Dercio TembeIT AssistantAsked:
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you can use the same dns name for both internal and external access. but the main concern is to make sure all your internal users are using local DNS server for name resolution, and the DNS server is configured with correct records.

It is highly recommended by Microsoft to have separate server for exchange installation and not to use the DC.

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Ideally, if you host your own website, you should separate your front-end web server from your internal subnet. That is a precaution against web-based exploits using makeshift requests.
Best idea for a small organization is to have the web server in a DMZ with a secured pipe between back-end applications, if any (product or client databases, etc.)

If you can separate the two, then it's no problem in using the same DNS.

In DNS management the following is essential:
having good forwarders. User the ones provided for free by your ISP plus one good free DNS forwarder like
Also make sure root hints are activated.

Also have a good firewall or endpoint protection (AV on your client machines).
Madan SharmaConsultantCommented:
you can use the same dns ENTRY  internal and external users without having any issue. There will not be any issue in installing exchange or DC in y our environment.

But if you have any hosted app or website with any third hosting service provider then please take care about them to point out them with appropriate IP of service provider

Good luck..
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There's no problem having the same name for Internal and external DNS. My professional advice is to differentiate the Internal with a .local e.g., ABC.local for internal and ABC.COM for external. Ensure that all internal users are directed and pinted to the right DNS for quick resolution of addresses and webseite while the Internal DNS points to the External DNS as well.

Secondly, Installing your Exchange on a DC is not much of a problem depending on the size of your organisation and the size of your mailbox server. professionally, it is better to install Exchange on a seperate server for so many reasons such as;
Not over working the DC
Allowing enough hardware resources for both servers
Alternatively, you can also make the Exchange server a secondary DC for replication just incase anything goes wrong with the primary DC.

Hope this helps :)
Dercio TembeIT AssistantAuthor Commented:
Thank you every body!!!!! Good answers! I have one more question regarding exchange server.
My organization have 1 DC  (where is installed AD+DNS on windows 2008 R2):
I joined other server as member of this domain to install exchange server 2010. I did the installation succefully without any error message.
EXTERNAL DNS ------  My ISP give me the external domain ( with MX and A record and also the reverse DNS for the public IP.

INTERNAL DNS--------- I have to do any configuration in my internal DNS to receive and send mail? Is there anything to do with MX Record? I have to add the MX Record on Domain controller/DNS ??? Is there anything to do in domain controller that function as  internal DNS?

Thanks you every body!
Madan SharmaConsultantCommented:
You have to point the mx records to your exchange 2010 to receive mails on it. Do a netting with your exchange local IP to public IP on your firewall and allow the required ports on your firewall i.e. 25 (SMTP) 80, 443 (Web Access) 135 UDP for outlook etc. Also configure send / receive connector on exchange. Once all this will setup then point the mx record to your exchange. And also set A records for your outlook wep app.
Dercio TembeIT AssistantAuthor Commented:
You mean the MX Record will be on DNS Server (Domain Controller) and pointing to my mail server?

Madan SharmaConsultantCommented:
I mean to your external DNS. You have to point mx to exchange in external DNS to receive mails globally.
This article will assist you with understanding MX records and configuration of MX records on your DNS. There are different scenarios which I believe covers yours. See link here

Hope this helps :)
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