ICANN apparently released an advisory back in late 2007 that they would be moving one of the root servers (one of twelve) to another IP address.
Unfortunately, most system administrators have missed this tip, since not everyone pays attention to ICANN advisories (I’ll admit that I sure don’t). This means that suddenly one of your root servers will go which will wreak havoc on your DNS. It also means that if someone were to rogue server the old IP address, then there could be DNS poisoning.
The older IP is 184.108.40.206 whereas the new IP address is 220.127.116.11.
So if your DNS servers need to be updated, do a quick check and make the change.