Short message translation:
There are DoS conditions in Windows 2000 built-in NAT server. Tested configuration: Windows 2000 English Standard/Advanced Service Pack 4 + Update Rollup 1 for Service Pack 4 with NAT server enabled. While routing packets with options "Loose Source and Record Route" defined by RFC 791 through server, Windows crashes to BSOD with error in tcpip.sys or ntoskrnl.exe, or system hangs or system began instable work. It doesn't metter if packets are from internal or external networks. Use attached script to test vulnerability. On Windows 2003 problem doesn't present. It's also likely same problem to present in Windows 2000 + ISA 2000.