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?

**Update:**

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?