UDP Broadcast Issues with Service Pack 4 (197511)
The information in this article applies to:
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Server 4.0
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.
REFERENCES
Winsock supports a socket option (SO_BROADCAST) that can be set to allow
the Recvfrom() call to pass broadcast datagrams to the program. The
default setting for this option is "Off." More information about the
SO_BROADCAST option and the functions used to set socket options is
documented in the Platform Software Development Kit (SDK), which is
available online at the following Microsoft Web site:
Modification Type: | Major | Last Reviewed: | 8/10/2001 |
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Keywords: | kbinfo KB197511 |
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