Windows NT 4.0 build 1249

Windows NT 4.0 build 1249.1 is a build of Windows NT 4.0, mentioned in an internal Microsoft document named  from the Windows NT 4.0 source code. It identifies this build as the Shell Update Release (SUR) and also mentions IIS 1.0 build 157, which was codenamed Gibraltar.

1. The performance of Gibralatar (157) on NT 4.0 (SUR) build 1249 showed about 5 to 10% improvement. Most of the improvements came from SUR kernel and TCP driver changes. 2P on x86 showed the largest improvement of about 20%.