There are different problems that can occur with Virtual Private Network (VPN) connections. Given that establishing a VPN requires you to first establish an Internet connection then connect to the VPN server, there are two points of failure, which makes troubleshooting more complex.
A VPN connection requires that both the client and the VPN server be connected to the Internet. The client connection can be either via a direct dedicated connection or a dial-up connection to the client user’s Internet Service Provider (ISP).
The dial-up connection presents the first point of failure, so it is important to ensure that the client is properly connected to the ISP. Do this by checking the status of the dial-up connection. Attempt to ping an Internet host. If you are able to do so, you have a connection to the ISP. If not, you will need to troubleshoot your modem configuration and/or Dial-up Networking.
The most common VPN connection problems fall generally into one of the following four categories:
- Problems related to the Internet connectivity on one or both sides
- Problems related to VPN server configuration
- Problems related to VPN client configuration
- Invalid credentials (logon failure)
You must have a valid username and password that will allow you to connect to the VPN server. Otherwise, you will receive this message:
Your credentials have failed remote network authentication
You will be prompted to re-enter your username and password (and logon domain, if applicable). Ensure that you are entering the proper account name and password.
Your user account must be set on the server to allow remote access (although this is a server configuration problem, it is one to be aware of if your credentials are rejected by the VPN server). If you are sure the credentials you entered are correct, contact the network administrator or check the settings on the Dial-in tab of the user account properties sheet on the server.