I've had some success with an IPsec subnet-to-subnet VPN on a test network. However, getting a mobile client to work properly has been a dismal failure.
I'm seeing the following in the IPsec log after attempting a connection with Shrew:
Dec 6 22:00:57 racoon: ERROR: no configuration found for 172.31.254.70.
Dec 6 22:00:57 racoon: ERROR: failed to begin ipsec sa negotication.
From the Shrew side, everything seems fine. It doesn't complain at all. An interface appears with an appropriate IP address on the Windows box. However, pings to the remote network fail. Pings from the remote network back to the Shrew machine also fail.
This seems similar to what was reported here:http://forum.pfsense.org/index.php/topic,34646.0.html
As suggested in that topic, I've tried setting the Policy Generation to Unique and the Proposal Checking to Obey/Strict. Doing so gets Shrew to complain, but doesn't see pings working across the tunnel.
This is pfSense 2.0-RELEASE and Shrew 2.1.7.