VPN Connectivity Troubleshooting Checklist
1. Find out who is affected
a. The first step in troubleshooting any VPN problem is to determine who is affected by it. That information can go a long way toward helping you figure out where to start looking for the problem.
2. Double-check the VPN settings on client
a. Make sure the configuration settings are entered exactly as specified; re-enter the login information just in case.
3. Look for policies preventing connectivity
a. If you find that certain users are having trouble establishing connectivity, have them try to log in from a known good machine. If that doesn't work, there may be a policy in place preventing them from logging in
4. Check to see whether users can establish VPN connectivity
a. Start by determining whether the affected users can establish VPN connectivity. Remember, not all VPN problems involve connection failures. Sometimes, users can connect, but they can't access network resources. Determining whether the user can establish VPN connectivity will help you narrow down the areas in which you should be looking for problems.
5. Can You Access Network Resources?
a. This would not seem possible, if you cannot establish a VPN connection. However, there are many levels of such a connection that may allow you access to some resources on the network, but prevent you from other connections, such as password-protected areas, which may seem like an overall VPN issue. There could also be a an IP address problem. In a dynamic environment (DHCP), your connection could have been assigned an IP address that is in a disallowed range.
6. Check Windows Network Access Protection (NAP)
a. For administrators of Windows Server 2008, check to see if there are any NAP rules in place that would prevent certain types of remote access connections. It could be an issue if the computer connecting is not a member of the domain. NAP also uses a scanning process to vet out any issues pertaining to the...