1. Determine if you are having performance problems. Sometimes, you may find that although a VPN connection is functional, it is very slow. When this happens, you have to do some performance monitoring on your basic organization servers to ensure that they are not experiencing performance delay in progress.

Public service or system servers are the source of performance problems, you will usually have multiple users complaining about poor performance. If only a single user is complaining, the problem is likely to be related to that user's Internet connection. I at a friends place whose Internet service was so slow that I hardly checked my email. If that happened to an end user, he or she might assume that the hotel's Internet service was running at a normal speed but that the VPN server was having problems.


2. Double-check the VPN settings. If you're an employer, you IT Department will have provided you with instructions and login information for the VPN, and possibly a software client to install. Make sure the configuration settings are entered exactly as specified; re-enter the login information just in case.

3. Test connecting to resources by IP address rather than server name. You should try connecting to network resources by their IP address instead of their name. If you can access previously difficult to get resources by using IP addresses, you can bet that a DNS problem is to blame. If that happens, you should check to see which DNS server VPN clients are configured to use.

4. Make sure you have a working Internet connection. Launch your browser and try visiting different sites to make sure your Internet access is really working. If you're on a wireless network and have Internet connection or signal strength problems, you'll need to first solve wireless connection problems before you can use VPN.

Read complete list at: http://trendymediablog.com/2014/07/vpn-troubleshooting-guide-for-remote-workers/