VPN Failed To Connect Due To Tunnel Error

Asked By 60 points N/A Posted on -

Now can someone tell me what this tunnel option is?

I am fed up of seeing it again and again.

I was establishing a net lab at a School.

I installed VPN server on the server machine and it worked well.

Then I installed VPN client end on client computers.  

It got installed but the client computer on which I had installed VPN Client gave me this error, "Failed to connect to the server invalid tunnel option".


Failed to connect for the following reason: Invalid tunnel options.

Now I can’t troubleshoot because I don’t know what this tunnel option is and where it is in the client VPN or Server VPN and how to make it valid.

If anyone out there knows what this error means and if  there is any solution to it then, I am waiting for your replies do reply.

Best Answer by Sharath Reddy
Answered By 0 points N/A #121880

VPN Failed To Connect Due To Tunnel Error


The protected network configuration must be checked, in the crypto ACLs on both sides. The local net on the initiator, is the remote net on the responder and vice-versa. Special attention must be paid to the wildcard masks and host addresses versus network addresses.

The 'Type of VPN' must be selected and once you know the type of tunnel to use for your deployment, then set the type of VPN to that particular tunnel type on the VPN client side.

This can be set by clicking, "Network connection' icon on the bottom right of the task bar, select your connection, right click and go to properties then click securities tab under 'Type of VPN'.  

Select the interested VPN tunnel type.

Best Answer
Best Answer
Answered By 574115 points N/A #121881

VPN Failed To Connect Due To Tunnel Error


Since you did not mention anything about the VPN program you used for the server and client computers, it’s hard to determine the cause of the problem.

I think there is no incompatibility problem here since you were able to successfully install the application on both server and client computers and in this case, we can now eliminate this possible cause. As far as I remember, when I was still using a VPN service before, the program needs several factors to be able to establish a connection.

The VPN client needs a TAP driver to work. If your computer doesn’t have it, the client will not be able to establish a connection to the VPN server because the TAP driver is the component responsible for the tunneling of the connection.

Check if the computers are already installed with a TAP driver because if they don’t then this is probably what’s causing the error. To download a TAP driver, visit OpenVPN package for Windows.

The download package includes the TAP-Win32 Virtual Ethernet adapter driver.

To install it, simply run the installer. When the TAP driver installation dialog box appears, select Continue Anyway to proceed with the installation. This is the screenshot of the TAP-Win32 Virtual Ethernet adapter driver installation dialog box.

The VPN client also needs to be configured with the correct UDP and TCP ports to establish a UDP or TCP connection. Also when using a proxy for the VPN, you need to specify the correct IP address for the parent proxy as well as its port number.

Besides setting the UDP and TCP ports, you also need to specify the working local port number that will be bind together with the UDP or TCP port number.

When the VPN client attempts a connection, the local port number set will be used to connect to the specified UDP or TCP port. It is like an ID to enter the correct port and establish tunneling.

To better understand what’s going on with your programs, better consult the manual that comes with it.

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