I have recently had an issue with a clients ADSL line, which decided to be a right pain, it usually had around 4mbps, then one week it decided to drop down to dial-up speed. It was absolutely awful, very difficult to do anything, when they have an office with 30 workstations chugging away.
We raised a ticket with the ISP in question and long-story short, we had to get a new line installed, it turns out the line was damaged somewhere between the building and the exchange.
So now that we were presented with a new IP range, we had to reset lots of devices, printers, scanners, access points and of course the servers, proxy server and static-ip PC’s.
All the DHCP PC’s would automatically get the new IP once we had change the scope on the DHCP server, so we thought.
But it didn’t and the reason is, that you must remember to restart both the DNS and DHCP services otherwise the Microsoft Server 2008 will not use the new scope!