We are testing a VPN connection in L2TP/IPSec with a pre-shared key in ms windows 2003 server.
The VPN is working correctly when used from an ADSL line that goes thru a Netgear adsl router (udp ports 500, 4500 and 1701 are opened) but FAILS when we use an ADSL line that goes thru a CISCO 2800 router.
We cant directly view or modify the CISCO 2800 configuration so we ask here.
We have analyzed the traffic with ethereal and the communication logs seems to fail in communicate ESP packet.
Can be a problem of the CISCO 2800 configuration? The ESP traffic must be enabled to work or is enabled by default when the port 500, 4500 are opened?
Thank You Roberto