No announcement yet.

Different SMTP Domains under single exchange 2007

  • Filter
  • Time
  • Show
Clear All
new posts

  • Different SMTP Domains under single exchange 2007

    Dear admin,

    I have gone through the article how to configure different smtp domains in exchange server 2007 using Authoritative domains and am clear about the point. But now my query is how to configure the MX records according to my below scenario which am implementing right now.

    AD root forest : abc.local (single forest single domain)
    Exchange server: (exchange server 2007 Sp1)
    We have 4 divisions under one roof, right now they all are using external hosting email. According to that I configured authoritative domains, now I have to re-configure the MX records from my hosting control panel to my new exchange server. (my doubt is here, letís take the below example of 1 division)

    Registerd Domain name:

    My public IP is configured on my juniper firewall from there I can create a rule to NAT it to my Internal exchange hub transport server (, now which name I have to use for configuring the A record and MX record? Below am configuring the same correct me if am wrong A 83.xx.xx.xx
    group1 MX 10

    Doubt 1

    If I configured like this there is no such servers inside my LAN named I have only, yes itís true that I have an authoritative domain+ email address policy for the, but do I have to change anything in my internal DNS? External request will hit my firewall from there I will NAT to the hub transport server. Am I doing right guys? anything else is required? Why am asking because is now pointed to external email hosting company and email is running live, weekend am planning for the MX change and it will take 24 hours to propagate.

    Doubt 2

    I have to publish my OWA and POP3 for the external users. How can I publish? Beacsue I cannot register my abc.local, am okie with any name like

    and for POP3 I would like to have , where I have to configure all this? I am planning to use direct publishing by using Client access server, but from the ISP side what all I have to do?

    Kindly give me your valuable suggestions, thanks allot

  • #2
    Re: Different SMTP Domains under single exchange 2007

    Here are answers for you:

    Doubt 1: It doesn't matter what the internal server name is. The public DNS A record of just needs to be set to the public ip address that you are going to NAT to your internal Exchange server. So for example the public DNS A record of is and you NAT that to your internal Exchange server ip address of Also, it won't take 24 hours to propogate. DNS records don't propogate. No other DNS server except the ones at your hosting company have a copy of your DNS records. What happens is this: A host looks up the MX record for your domain and finds it and the corresponding A record and puts that info in it's DNS cache for the period of the TTL of those records. It will not look up that info again for the period of the TTL. When you change the MX and A records it will only affect hosts that have performed a lookup and still have the info in their DNS cache as they will not perform a new lookup and get the new info until their DNS cache for those records flushes out (again, for the time period of the TTL for those records). For hosts that don't have the info in their DNS cache they will perform a lookup and get the new info immediately. As you can see, it is likely that only a very small number of hosts will be affected when you change the A and MX records. If the TTL of those records is 8 hours then only hosts that have looked up that info in the last 8 hours will be affected. So what is the current TTL of those records?

    Doubt 2: Again, this is the same as Doubt 1. It doesn't matter what the external name is as long as you NAT it to the correct public/private i address combination and get the common name of your SSL certificate correct. If you want OWA to be then that will be the common name of the SSL certificate.


    • #3
      Re: Different SMTP Domains under single exchange 2007

      thx alllotttttttttttt joeqwerty for your quick response, I would like to clarify one more point

      if I want to use without SSL what i have to configure? now my internal owa url is its using the Self certificate, do I have to delete the certificate from IIS? or I just have to NAT the to my CAS server?

      kindly revert


      • #4
        Re: Different SMTP Domains under single exchange 2007

        You shouldn't need to delete the certificate, just NAT to the server. Depending on how IIS is set up you may or may not need to use https externally.


        • #5
          Re: Different SMTP Domains under single exchange 2007

          a'right, i will update once my setup is complete...thnx once again