If your main PC is connected to LAN2, and you want to remotely manage equipment on LAN1 ( ie. IP Phones, ATA adapters, etc), then this procedure is your holy grail!!!
sample system specs:
LAN1 = 10.10.10.1
LAN2 = 18.104.22.168
1. NO ip routes are needed on the IPO system!!
2. Enable NAT ONLY under LAN1
3. Using the above specs as an example, add a new route to the PC connected to LAN2 (route -p add 10.10.10.0 mask 255.255.255.0 22.214.171.124)
4. end of procedure!! simple huh?
this took me a while to figure out, weeding out all the relavant data here on Tek Tips. This procedure is solid, and should work great for you. If done correctly, you should be able to ping anything on LAN1 from your LAN 2 connected PC. I didnt test the reverse of this procedure (LAN1 to LAN2), but i imagine it would work equally as well considering the proper routes were setup on your PC and NAT is enabled under LAN2.