VPN services are generally very reliable and, when there are problems, it usually comes down to a configuration issue with the client computer or the hardware that the user is using to access the Internet. Here are three very common VPN errors that people run into and ways that you can troubleshoot and, possibly, repair them on your own.
This error will pop up when your computer is unable to establish a connection to the VPN. Most of the time, this stems from a problem with a firewall on the user’s computer or their router. In some cases, it may also be caused by a slow connection.
The first thing you’ll want to do is check your firewall. The exact process for fixing the problem will differ depending upon which firewall you use, but the port that is the problem will be the same. Your VPN needs to communicate over port 1723. Open up the port for IP protocol 47. This protocol is also known as GRE.
Other potential culprits include the NAT settings. If you have additional hardware between you and your VPN, check to make certain that the correct ports are open.
This usually happens when you have a piece of hardware between you and your VPN that does not allow GRE communication. It may also occur because you’re unable to get an IP from the DHCP for the VPN. The solution to this error is largely the same as the solution to error 800. Check your firewall and make certain that TCP port 1723 is open for IP protocol 47 communication.
This error occurs when you cannot complete the connection to the server, though you may be connected to some degree. The solution is usually to take a look at your security and see if it conforms to the requirements of the VPN. It may be something as simple as an unsecured password.
In some cases, hardware issues may also cause this error. One possible solution is to re-download your drivers and, if necessary, your firmware to make certain that everything is compatible with the VPN service. In some cases, this issue will require you to make rather complex changes to your active directory. If this is the case, you will need to consult with the documentation for your VPN determine what the settings should be set to.