VPN over GRE Tunnel drop connection

[dwhisinnand]

Senerio:

We have on site contractors that are trying to use a VPN to establish a connection to their HQ through our guest network. The contractors on our site are at site B and our internet router is at site A?the two site Guest Network is connected via a GRE Tunnel.

Problem:

The contractors can initially establish a VPN connection to the HQ, but the VPN will eventually disconnect anywhere between 5 and 30 minutes.

Is this an mtu problem somewhere? Any ideas welcome

[dwhisinnand]

I see the clients the following message in the VPN Client log:

8 17:53:15.646 07/26/06 Sev=Warning/2 IKE/0xE3000099

Immature Navigation Termination due to error (Navigator:195)

[radwayscisco]

CSCei73829

Symptoms: Cisco VPN Client 4.6.x connected to a Cisco IOS router configured as the VPN Server passes traffic correctly but after phase 2 SA rekeys, repeated phase 2 SA rekeying occurs and the Cisco VPN Client disconnects. The client log shows:

2007 20:18:34.732 08/06/05 Sev=Warning/2 IKE/0xE3000099

Immature Navigation Termination due to error (Navigator:195)

The router debug shows:

IPSEC(update_key_lifetimes): volume lifetime reached 0, dropping SA sibling

Conditions: This symptom has been observed with Cisco VPN Client 4.6.x connected to a router configured as the VPN Server and running Cisco IOS Release 12.4(2)T.

Workaround: Downgrade the router to Cisco IOS Release 12.4(3).