The Cisco AnyConnect VPN client is Cisco’s SSL VPN client offering. Cisco currently supports this VPN client and the legacy IPSec VPN client, called the Cisco VPN Client. The Cisco VPN client will be phased out over time. This can be seen by the Cisco VPN Client FAQ explaining that 64 bit operating systems are not supported by the Cisco VPN client, but are supported by the Cisco AnyConnect VPN client.
With this in mind, it’s important to understand possible scenarios where the AnyConnect VPN client could break. One scenario is shown below. In this scenario, the AnyConnect VPN client works for all users except for one user. This user had the AnyConnect VPN client working for period of time, but found that it didn’t work one day. The error message that the user sees is shown below.
Since other users can connect to the network, through the AnyConnect VPN client, the problem can be narrowed down to something on the user’s computer. The user is using the correct VPN settings. In fact, the error message shows up after successful authentication. There do not seem to be any other settings, within the AnyConnect VPN client, that could be modified to fix the problem.
The key to understanding the problem is recognizing that the AnyConnect VPN client uses SSL. In addition to the client settings, the Microsoft Internet Explorer settings need to be taken into account. For this particular problem, the web proxy settings were set. This caused the failure shown above. In order to get around this, the VPN server IP address, must be added to the “Exceptions” list. This is shown below.
After adding the VPN server IP address to the “Exceptions” list, the AnyConnect VPN client connects successfully. In general, this example serves as a reminder to look at the Microsoft Internet Explorer settings when troubleshooting AnyConnect VPN client connectivity problems.