Cato Networks Knowledge Base

IP Routing Prevents Windows Client Authentication

  • Updated


When IP routing is enabled on Windows, authentication of the SDP client will fail.



Determine If IP Routing Is Enabled:

To determine whether IP routing is enabled on your Windows device, execute the 'ipconfig /all' command.


If the IP routing is enabled, the SDP client will not be able to connect. The reason is because when IP Routing is enabled, it interferes with the SDP Client authentication process. The authentication serviceĀ  only accepts requests with a source IP the client received on establishing the unauthenticated tunnel (, otherwise authentication requests are ignored.

With the IP Routing feature disabled, the source IP used is determined by the authentication service destination IP. The operating system will find in the routing table which interface has route to the authentication service destination IP. SDP Client then adds a route to the authentication service IP via the Cato tunnel interface, so it takes the correct source IP of Cato tunnel interface.

On the other hand, if IP Routing is enabled, Windows can choose a source IP from other interface (for e.g., the WiFi interface), so the authentication requests were ignored


Disable IP routing on Windows so that the SDP client will use the IP address of the CatoNetworks adapter forĀ  authentication. To do that,

  1. Open the Windows Registry Editor by pressing Win + R, typing "regedit," and pressing Enter.

  2. Navigate to the following registry key:

    • If the "IPEnableRouter" value doesn't exist, you can assume IP routing is already disabled.
    • If the "IPEnableRouter" value exists and is set to "1," it means IP routing is enabled. To disable it, right-click on "IPEnableRouter," select "Modify," and change the value to "0."

      In the right pane, look for a DWORD value named "IPEnableRouter."

  3. Close the Registry Editor.


After making this change and rebooting Windows, IP routing should be disabled.

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