My new box (GALINSTAN) is up and working great - I'm writing this from it. However, it is running Windows XP 64bit (which is great fun) and I lack wireless cards that have network drivers (from what I can find out, only one or maybe two companies have got 64bit drivers currently, which is a shame). So I decided to simply route the small physical LAN in my room through one box that can use the wireless. Here's a summary of before:
Nice and simple - each box is on both the wireless (main) LAN using DHCP and also on my physical mini-LAN by fixed IP. I added Galinstan thus:
Then came the fun bit. I needed one of the three original boxes to route between the networks. So I just enable IP routing, right?
A few hours later, I finally found the key - literally.
Set that and reboot. At least ipconfig /all agreed with me now. Of course, it's all very well having the box route, but everyone else needs to know this...
This was easy, luckly, and just involved setting the gateway on each box (BRONZE, SILVER, GOLD and GALINSTAN) to 41 (i.e. GOLD), which I'd picked to be the router. That almost works - packets go flying out onto the wireless network, but of course the replies don't know how to come back! So a single persisten route was added to PLATINUM (the wireless router box) to route anything for the physical mini-LAN to GOLD's wireless IP (which I'd now reserved in the DHCP server so it was effectively static).
I now have 4 boxes in my room, all with 'net access, and all accessible from the house router (meaning I can forward public ports to them for services as nessessary).