Our remote users in Germany are provided with a mixture of Vodafone 3G Mobile Connect Cards (PCMCIA) and "USB sticks" for cellular broadband access. Installed on their laptops is Vodafone's Mobile Connect Client & Cisco VPN client version 5.
To connect, they first connect to Vodafone's "VPN access point" -- Vodafone's VPN only service offering. Once connected, they VPN into the network with the Cisco client. All users connect to a Cisco 3020 Concentrator.
Users are able to access network resources, however, they lose connectivity after 5-10min. What's unusual is, it doesn't look like the VPN session drops since the padlock in the right hand corner remains locked; they just can't access network resources.
a) We had a user establish a VPN session then immediately start a continuous ping to an internal device's IP address. The connection stayed up for 20min before requests started timing out.
b) We enabled "IPSec over TCP" on the client and Concentrator side, no change.
What could possibly be causing this behavior?