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I'm trying to point a domain to my internal exchange server

Hi all,

My company has an Exchange 2000 server running on W2K server.  We have only been using it for internal mail and have been using an outside company to host our internet mail.  Due to a recent problem with this company I have been instructed to investigate taking control of our email.  I purchased a domain for testing, changed the A record to point to the WAN address of my firewall, and set a rule to route SMTP to the internal address of my exchange server.  Now for the questions!

What should I be pointing the MX record for the domain to?  Should it be pointing to mail.domainname.com or some reference to my internal server?

Should I change the default DNS addresses that come with register.com or should I change them to the ones provided by my ISP?

I have already added the domain in recipients on the exchange server.

Anyone have a link to a simple how to guide for setting something like this up?

Basicly I have an internal mail server and a firewall.  I want to send mail from outside to the internal mail server.  I've tried sending mail to the new domain and this is the response I'm getting.

Permanent Failure: Bad destination system address

Obviously I've got something wrong.

Thanks for the help!
5 Solutions
MX records point to hosts only.
Therefore if you have setup an A record of mail.domain.com to point to, then you set the MX record to point to mail.domain.com

Thats it. Nothing else needs to be changed.
You already have the domain in recipient policy.
Don't change the DNS servers - there is no need.

in a simple single ip scenario you would typically have a single A record (mail.domain.com) and an MX record that would be reference the aforementioned A record.

so if you have a single ip of and you have mail.domain.com the follow should exist:

mail      IN      A
@      IN      MX      10      mail.domain.com.

thats what it sounds like you need to do at least.  That will allow public mailservers to find your email server and deliver accordingly.
Lee W, MVPTechnology and Business Process AdvisorCommented:
Set your MX record to point to your mail server BY NAME.  If your mail (exchange) server is mail.testdomain.com, then you need:

A record for mail.testdomain.com
MX record pointing to mail.testdomain.com

Make these entries on whatever your primary name server is according to your registrar.

And as you have, you need port 25 open (if you have a T1 you almost certainly have the all ports open as far as the ISP is concerned.  If you have DSL or cable, you MAY need to contact them and make sure the ports are open.

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The MX record can point to any name you want...as long as that name resolves to your external IP address. "mail.yourdomain.com" is one convension, but it doesn't need to be.

You can leave register.com controlling the dns...but make sure the records are correct. You need an MX record pointing to some name (mail.yourdomain.com) and that name needs an A record for the external ip address of your network (assuming your exchange server don't have a public IP).  

Then you need to forward port 25 on your firewall (the ip that mail.yourdomain.com points to) to your internal exchange server. If you let us know what kind of firewall you have, we can help you do this too.

Then it should work, assuming the dns changes have propagated.
you need a mx record pointing to yourdomain.com or mail.yourdomain.com
if you use the latter, you need to make sure mail.yourdomain.com will resolve to your ip
joepackagingAuthor Commented:
I have a sonicwall 3060 with enchanced OS.  Just occured to me.  Do I need to point the A record to the Wan interface  public address or the gateway address?
Lee W, MVPTechnology and Business Process AdvisorCommented:
You need to point it to whatever address is visible to the world.

If all traffic goes through that, visit www.whatismyip.com and use the address it reports.
joepackagingAuthor Commented:
I think I see my mistake.  When I changed the A record at register.com I forgot to put "mail" in.  so it was actually pointing to .domain.com instead of mail.domain.com.  Well, 12 to 24 hours before I can test.  I'll let you all know.

Lee W, MVPTechnology and Business Process AdvisorCommented:
Some DNS servers update right away and may not take that long - you may also want to consider hosting your own DNS to have better control over this.  In conjunction with a third party, such as zoneedit.com, you can have a reliable DNS setup (I use it for my own domains and have been hosting my own domains for about 1.5 years now with no problems).
For Register.com does this sound right?

A Record
mail.sasso.com points to xxx.xxx.xxx.xxx

MX Record
Host Name  Priority  Mail Server
sasso.com   High     mail.sasso.com


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