We have a 3000 VPN concentrator that we
use to connect remote users to our internal network. It works fine when users originate the connection from behind a device that does NAT. If the users are behind a PAT device they can connect to us (using the Cisco VPN client) and I can
see the TX and RX counters increase on our side but on the client side they typically see the TX counter increment but not the RX counter. On the Concentrator I enabled "IPSEC over NAT-T" and then none could connect. Any ideas?