Microsoft KB Archive/197511

= UDP Broadcast Issues with Service Pack 4 =

Article ID: 197511

Article Last Modified on 10/31/2006

-

APPLIES TO


 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 4.0 Standard Edition

-



This article was previously published under Q197511



SUMMARY
When you apply Service Pack 4 for Windows NT version 4.0, TCP/IP, Windows Sockets, and Simple TCP/IP services are modified to be resistant to attack. This modification may cause a loss of functionality in programs that use User Datagram Protocol (UDP) broadcasts.



MORE INFORMATION
Because of the security issues fixed in Service Pack 4, the default behavior of Winsock sockets has been changed. Sockets now receive broadcast datagrams such as UDP broadcasts only if they have been explicitly set to do so. Prior to these fixes, any program that issued a Recvfrom call would receive broadcast datagrams.

Programs affected by this change should be modified to operate as expected with Windows NT 4.0 Service Pack 4 or later.

