Microsoft KB Archive/183902

= Dead Gateway Detection Is Not Triggered During Logon =

Article ID: 183902

Article Last Modified on 12/5/2003

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APPLIES TO


 * Microsoft Windows NT Server 3.5
 * Microsoft Windows NT Server 3.51
 * Microsoft Windows NT Server 4.0 Standard Edition
 * Microsoft Windows NT Server 4.0 Enterprise Edition
 * Microsoft Windows NT Workstation 3.5
 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows 95

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This article was previously published under Q183902



SYMPTOMS
A Windows 95-based or Windows NT-based computer that is configured with multiple default gateways may be unable to connect to its logon server when the computer starts.



CAUSE
If the first default gateway is unavailable, the logon process does not trigger dead gateway detection. Without a domain controller on the local network segment, you are unable to log on to the domain.



RESOLUTION
To resolve this issue, use one of the following methods:  Install and configure a domain controller on the local network segment. Install a routing protocol on your Windows NT-based computer, such as Routing Information Protocol (RIP) for Transmission Control Protocol/Internet Protocol (TCP/IP) on Windows NT Server or Silent RIP for Windows NT Workstation. For more information, please see the following articles in the Microsoft Knowledge Base:

172514 Silent RIP for IP Available for Windows NT Workstation

169161 Registry Parameters for RIP for IP version 1

NOTE: Silent RIP is not available for Windows 95.

  For Windows NT, Windows 95, and Windows 98-based computers, you can enable the Internet Control Message Protocol (ICMP) Internet Router Discovery Protocol (IRDP) packets on all of your routers. The following text is an excerpt from Request for Comments (RFC) 1256:

     The ICMP router discovery messages are called "Router      Advertisements" and "Router Solicitations. " Each router periodically multicasts a Router Advertisement from each of its multicast interfaces, announcing the IP address(es) of that interface. Hosts discover the addresses of their neighboring routers simply by listening for advertisements.

This is one way of testing for dead gateways. This solution requires that routers be configured to send IRDP packets, but currently has not been implemented in Windows NT 4.0. Windows 95 requires a Windows Socket update 2, while Windows 98 natively supports IRDP. For additional information, see the following article or articles in the Microsoft Knowledge Base:

182108 Availability of Windows Sockets 2.0 for Windows 95



For additional information, see the following article or articles in the Microsoft Knowledge Base:

223756 IRDP Client Support Added to Windows NT 4.0



MORE INFORMATION
Switching to the second gateway occurs only if there is already an existing connection-oriented TCP session over the route to the first configured gateway. Connectionless datagram-based traffic such as an ICMP or Network Basic Input/Output System (NetBIOS) packet does not trigger the change to a secondary gateway.

For more information, please see the following articles in the Microsoft Knowledge base:

128978 Dead Gateway Detection in TCP/IP for Windows NT

171564 TCP/IP Dead Gateway Detection Algorithm Updated for Windows NT

You can obtain additional information from RFC 816, "Fault Isolation and Recovery."

For information about obtaining RFCs, please see the following article in the Microsoft Knowledge Base:

185262 How to Obtain Request for Comments Documents from the Internet

Keywords: kbnetwork kbprb KB183902

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