Home » Windows » Help Desk Processes » [solved] The VPN client was unable to successfully verify the ip forwarding table modification. A VPN connection will not be established

[solved] The VPN client was unable to successfully verify the ip forwarding table modification. A VPN connection will not be established

Users may get the “A VPN connection will not be established”  while trying to connect to the VPN using anyconnect.

The below message is somewhat misleading , it points to the internet/cable provider. however there is a easy fix that works all the time.

“The VPN client was unable to successfully verify the ip forwarding table modification. A VPN connection will not be established” 

This is also documented that it is known bug by Cisco

https://quickview.cloudapps.cisco.com/quickview/bug/CSCvf16310

Cisco Bug: CSCvf16310 – IPv6 Addresses intermittently assigned to AnyConnect clients

Products (1) Cisco ASA 5500-X Series Firewalls

Known Affected Releases

9.6(3.1) 9.7(1.2) 9.8(1)

Below is the screenshot of the error message you may get.

 

“solution”

Here is what you will need to to.

  1.  Go to “start” “run” “cmd” and type the command “ncpa.cpl” launch the network connections window.

 

2.  This is just  a quick way to get to your network connections screen and you can also launch the network connection window by navigating to the control panel.

 

3. Right click the connection and choose properties and un-check  the “Internet Protocol Version 6(TCP/IPv6)”

Now right click the Cisco Anyconnect client and choose “Network Repair” and this should fix the problem.

 

 

Try connecting again and this time it will work and the reason behind is that your adapter chooses IPV6 which may a preferred path by the service provider.

let us know and thanks for reading this.

 

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