Help need to isolate two networks on same router

[AMD Die Hard]

I own a business and I am sharing an internet connection through a linksys router with another business. My computers are a mix of XP pro and XP home. Their computers are win 98 and ME, but seem to have some advanced networking features. My computers are configured on one network named "A" and the other business on its own network named "B". The problem is that there is noting stopping the "A" comuters from seeing the "B" network and vice versa. How can I keep these netowrks separate and private?

 

[JeffMD]

The cheapest way is a firewall on all your computers to filter out any packets coming from the other computers. Otherwise if you want total iscolaation, get another router for your network, and plug the wan side into the lan side of the first router.

 

[Fardringle]

I actually set up a network very similar to yours recently with three small businesses in the same office and sharing the same DSL Internet connection.

All three offices deal with personal and financial information so are concerned with security. The office was on a pretty slim budget so I ended up buying four identical Linksys BEFX41 routers (fairly inexpensive with a decent feature set) and connected one to the DSL modem as the main router, connected the other three routers as clients to the main router and named them based on the individual business units and gave them each static IP addresses so I can route desired incoming traffic to the appropriate business, then connected the individual business computers to their own separate routers. This gives everyone Internet connectivity, allows me to administer everything easily since all routers are identical, gives full access between the computers in the individual businesses, and completely prevents anyone in one business from accessing resources in the other two business units unless I specifically give them permission to do so on the routers.

It's not a "pretty" set up like a nice SonicWall router/firewall would provide, but it was about 1/4 the cost of even a cheap SonicWall. 🙂

 

[AMD Die Hard]

Thanks Fadringle, that sounds like a winner to me! I have one router, so I need two more to finish setting up two offices.