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Our ISP is changing our static IP soon and we have a Windows 2003 server that's running as a webserver: hosting web pages, e-mail with Exchange, DNS and Active Directory.

My question is: is it as simple as logging into the domain registrar and pointing to the new IP, or is there more work involved on Windows 2003?


I logged into the domain resister and I found that the www, @, mail and all the IPs were identical to our internet external IP, but the MX records have 5 entries with completely different IPs than our external IP.

So my question is do I keep those MX records unchanged after we change our internet IP?

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2 Answers

It depends. How are you using the current ip address? Do you have the ISP assigned ip address assigned directly to the server or are you NAT'ing it in your firewall to a private ip address on the server? If you're NAT'ing it then it should be a simple matter of changing your external DNS to reflect the new ip address and changing the NAT rules on your firewall.

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I'll more or less echo joeqwerty. However, you'll want to set up a temporary, secondary MX with the new IP address before the switchover, so you can avoid delays in email delivery. Find out what the TTL (cache lifetime) for your DNS is set at, and make sure that the time difference between adding the MX and changing the IP is greater than that. Or, just turn down the TTL to an hour or less, to prevent clients from caching the DNS for too long -- again, do this well before the changeover.

So in addition to updating DNS, you'll need to change the external IP address of your router, or of the server if it is directly connected to the Internet.

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