|"Your options it seems are to use ICS..."|
Guess what Internet Connection Sharing (ICS) uses? Our good buddy NAT! Still gotta do port forwarding configs, etc. to allow things to function.
Difference there is one Windows computer is publicly facing to the internet, which means if a hacker hacks that PC, they'll get to the other one very easily since both are windows machines. ICS is also more prone to problems than a good SOHO router, and requires the ICS hosting computer to absorb all connection attempts, do the actual NAT computations, and run a DHCP service. You also lose Stateful Packet Inspection (SPI) firewalls built into most current SOHO routers (SPI doesn't cause the problems the original poster was complaining about). Therefore, it's what he has now, but slower, less reliable, and less secure.
Therefore, his only real option is to get an additional IP address from his ISP, and use a hub or switch instead of a router. Again, you lose quite a bit of security and some in performance.
My point is it's common for people to get annoyed by port forwarding, etc. However, many overlook the benefits of being more secure.
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