While trying to login to a Cisco VPN from a Windows 7 laptop using Cisco AnyConnect Secure Mobility software, the software launched correctly, and I got a login prompt. My username and password were correct (as when I tried typing them wrongly I received a “Login failed” message).
The login session failed with an alert pop-up appearing with the text:
Unable to establish VPN
There is very little logging information available for the program. While the error is frustrating, in the majority of cases it has a simple fix, described below.
There may be other reasons why the error message “unable to establish VPN” appears, however this is one possible fix that is worth trying.
Disable Internet Connection Sharing. It turns out that if ICS is enabled on a wireless network interface, then the security settings demanded by the VPN cause the connection to fail.
To disable Internet Connection Sharing, from the Control Panel open “Network and Sharing”, right-click on the wireless connection and select “Properties”. In the window that opens, select the “Sharing” tab and unselect “Share Internet connection”.
Apply the change and try again to connect again, as normal, to the VPN using AnyConnect.
Was this fix helpful to you? Let me know in the comments, or if you resolved it some other way, equally, I’d be curious to find out what it was.
Addendum: This solution applies to Windows 7 (and possibly earlier versions), for Windows 8, a solution can be found here: