How to enable Dead Gateway Detection

How to enable Dead Gateway Detection

Dead gateway detection is used by the TCP component of Windows TCP/IP to detect the failure of the default gateway and to adjust the IP routing table to use the next default gateway when there are multiple default gateways configured.

To enable dead gateway detection, set the registry value EnableDeadGWDetect under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters to 1. To disable dead gateway detection, set the registry value to 0.

Note: 1. Dead gateway detection monitors only TCP traffic. If connectivity fails for other types of traffic, the default gateway is not switched.

2. Dead gateway detection can cause the default gateway configuration to change when a remote router fails. Remote routers in the path between the host and the destination that fail might also cause TCP connections forwarded along that path to fail and for the host to switch its default gateway. Because dead gateway detection relies on an end-to-end protocol (such as TCP), a host can switch its default gateway even when the current default gateway is fully operational.

3. The combination of multiple configured default gateways pointing to disjoint networks and dead gateway detection can cause confusing consequences. If you configure default gateways for both Internet and intranet interfaces, the result can be intermittent connectivity to the Internet or your intranet when dead gateway detection changes the active default gateway. For example, when the active default gateway points to the Internet and dead gateway detection switches the active default gateway to the intranet default gateway, DNS-based name resolution for Internet names and Internet-based connections can fail.

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