Article ID: 225344 - View products that this article applies to.
This article was previously published under Q225344
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/256986/EN-US/ )Description of the Microsoft Windows Registry
Your computer running Windows NT may stop responding (hang) or the computer's performance may degrade drastically when connected to an internetwork segment or to the Internet. Other symptoms may include:
This problem is caused by the receipt of multiple Internet Control Message Protocol (ICMP) Redirect packets that are used to change routing table entries. Too many ICMP Redirect packets in a short period of time may cause Windows NT to dedicate an inordinate amount of CPU time to update the routing table and cause the computer to stop responding. In many cases, this scenario indicates a denial of service attack through the use of a program to send multiple ICMP Redirect packets against a specific TCP/IP address.
To resolve this problem, obtain the latest service pack for Windows NT. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/152734/EN-US/ )How to Obtain the Latest Windows NT 4.0 Service Pack
After you have installed Windows NT 4.0 Service Pack 5, you can enable a Windows NT registry entry that allows your computer to disregard ICMP Redirects. To disable ICMP Redirects:
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows NT version 4.0 Service Pack 5.
For additional information about ICMP Redirect packets, please see the following article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/195686/EN-US/ )Explanation of ICMP Redirect Behavior
Article ID: 225344 - Last Review: September 11, 2007 - Revision: 2.2