A friend of mine running debian showed me a nice config item for the vpnc.conf file that sadly didn't work on my gentoo box. This works on debian: Target Networks 1.2.3.4/24 Resulting in the following route: 1.2.3.0 * 255.255.255.0 U 0 0 0 tun0 Thus making it easier to configure a vpn while still having access to other networks. Of course it is workaroundable by setting up the route manually.
This is applied upstream and we now use svn-snaps for vpnc.