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  • Change to a new ISP

    Dear all,

    Currently our email exchange is running using ISP A.
    We were planning to change to a new ISP B.
    What are the thing that I need to be aware when changing to a new ISP.
    I try to compile checklist before I change.
    1. new public ip at firewall?
    2. dns?
    3. mx?

    TQ

  • #2
    Re: Change to a new ISP

    Very important: Confirm ISP will give you SMTP email -- some don't

    Get new static IP
    Change MX Records
    Reconfigure router etc.
    Change exchange smarthost if required
    Check/test mail flow
    Tom Jones
    MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
    PhD, MSc, FIAP, MIITT
    IT Trainer / Consultant
    Ossian Ltd
    Scotland

    ** Remember to give credit where credit is due and leave reputation points where appropriate **

    Comment


    • #3
      Re: Change to a new ISP

      What I always do is get the new IP addresses in advance, and create an additional A record for the new IP address. Set that host as an MX record with the same cost. Then when it comes to switch over, the DNS change is already live. You just need to change the IP address on the existing A record.

      Simon.
      --
      Simon Butler
      Exchange MVP

      Blog: http://blog.sembee.co.uk/
      More Exchange Content: http://exchange.sembee.info/
      Exchange Resources List: http://exbpa.com/
      In the UK? Hire me: http://www.sembee.co.uk/

      Sembee is a registered trademark, used here with permission.

      Comment


      • #4
        Re: Change to a new ISP

        Hi all,

        Tq,

        Sembee, I think, it might be not possible to get the ip in advance. So how about that?

        Comment


        • #5
          Re: Change to a new ISP

          Expect disruption of email for up to 48 hours while the new MX records propagate
          Tom Jones
          MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
          PhD, MSc, FIAP, MIITT
          IT Trainer / Consultant
          Ossian Ltd
          Scotland

          ** Remember to give credit where credit is due and leave reputation points where appropriate **

          Comment


          • #6
            Re: Change to a new ISP

            normally they should be able to tell you in advance

            In addition to the things the others mentioned, you need to ensure you have a static ip.

            If you change your TTL on your MX records down to 1 hour might also decrease the time it takes to propagate
            Please do show your appreciation to those who assist you by leaving Rep Point https://www.petri.com/forums/core/im.../icon_beer.gif

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            • #7
              Re: Change to a new ISP

              deal all,

              the new line will either be ADSL or SDSL, I will gave a shot and ask the ISP if they will able to tell me the new public ip if i subscribe the new line.

              One more.
              ISP a dns = a.a.a.a
              new ISP b dns = b.b.b.b

              i should change the dns also right?

              Comment


              • #8
                Re: Change to a new ISP

                No need for disruption.
                Use the dynamic DNS method.

                Get a free Dynamic DNS host name with someone like dyn.com.
                Set the host to your current IP address.
                Add the host name to your MX records with the same cost. Make sure the TTL time on the dynamic DNS host account is low.

                When you change ISP, change the IP address on your dynamic DNS account first to the new IP address. That will be live within minutes. Also change your live MX record.

                Wait 48 hours and then remove the dynamic DNS host name (or not, as it can be useful to have in place).

                With regards to external DNS, why use ISP DNS anyway? Internal machines should be using only AD for DNS. If you want to use forwarders on the AD servers for DNS then use one of the generic ones like OpenDNS, DNS Advantage or Google DNS. Then you aren't dependant on the ISP for anything.

                Simon.
                --
                Simon Butler
                Exchange MVP

                Blog: http://blog.sembee.co.uk/
                More Exchange Content: http://exchange.sembee.info/
                Exchange Resources List: http://exbpa.com/
                In the UK? Hire me: http://www.sembee.co.uk/

                Sembee is a registered trademark, used here with permission.

                Comment

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