> On the other hand, your usage agreement probably restricts your
> "internet service" to a single computer, despite the tendency of
> providers to look the other way WRT things like NAT routers and
> wireless APs...

Nearly all Cable and DSL providers now explicitly permit multiple machines. 
I think the market forced them into it.

Do check your terms of service with Comcast. I am guessing that your 
residential service (which I am assuming it is) cannot be legally used by a 
business entity (which I understand is in the second house). Still: this 
does not give them the right to chop up your cable. On the other hand, to 
stay on the  right side of their terms of service you might have to be able 
to show them that the business side can't access the Internet.

A configuration like this would do it:

Cable modem in house A
-- ip addrfess between modem and router in house A to please ISP
Router in house A
Router in house B
-- local segment in house A is 192.168.0.x
-- link betwen houses is 192.168.2.x
-- local segment in house B is 192.168.1.x

Router B set up with explicit routing table with the only entry set up being 
from 192.168.0.x to go out over the 192.168.2.x link only an entry from 
192.168.0.x

Bob Ammerman
RAm Systems

ps: re: using a wireless system to share your Internet connecion with other 
households is almost certainly a violation of the terms of service 

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