This is an interesting scenario and one which I was able to play with using my current setup. I run XP under Parallels on my Mac mini. I regularly use a Cisco VPN under XP. I *thought* the solution would be to simply add a static route in OS X which used XP as the gateway (I use bridged networking). Despite much Googling and hair-pulling I didn't get it to work, but I know I'm on the right track. I figured I'd post the details of what I tried in hopes that someone else might be able to build upon it. Here goes:
XP IP details:
IP (via Parallels bridged networking): 192.168.10.6
Subnet mask: 255.255.255.0
Default gateway: 192.168.10.1
IP (from Cisco VPN client): 10.1.2.3 (last 3 octets changed to preserve anonymity)
Subnet mask: 255.0.0.0
The target network is 130.140.0.0 (first 2 octets changed to preserve anonymity) and the following entry exists in the routing table:
130.140.0.0 255.255.0.0 10.1.2.3 10.1.2.3 1
OS X IP details:
IP: 192.168.10.5
Subnet mask: 255.255.255.0
Default gateway: 192.168.10.1
I added what appeared to be the correct route:
sudo route add -net 130.140.0.0/16 192.168.10.6
End result: while I can ping machines on the target network from XP, I cannot ping them from OS X. I also tried adding the same route with netmasks of /8 & /24, but still no luck.
BTW - this post isn't meant to be a Parallels support request. I'm just a networking geek trying to help figure out what looked like an interesting problem.
