Cannot access server in different subnet

There is also another trick you can do to get around the router changes requirement. If you give all your computers a 2nd IP Address in the subnet of the servers then you will automatically be on that subnet and have a route to it as being "local".

This of course requires that the servers and the PC computers be on the same physical network (or wireless network).

A lot of people don't realize that you can send more than one subnet across a network switch hub. For example if you had to configure a new box hooked up to the network switch hub, but you are static IP to a different IP Address Range than the new box. Just add an IP Address to your workstation or laptop in the same range as the new box. And then you are able to reach that new box and change it to an IP Address in your normal networks range.

All computers and routers talk at Layer 2 across switch / hubs. They all use ARP - Address Resolution Protocol to find out the MAC Address for a particular IP Address. Once you configure 2nd IP address to a computer and try to access another IP Address on that new subnet, your computer will tell "Arp who has x.x.x.x" and the corresponding box (computer or whatever) will answer and tell its MAC address. Then your talking!!!!

So in the Internet, how is it that networks on different networks can communicate with each other? What exactly do you configure on the router that allows it to be able to allow two two different networks communicate with each other? Is a SOHO router capable of this?

thanks
K

It depends on which SOHO router you are talking about. Many inexpensive ones are based on Linux Operating System installed in flash in the router, and many can be updated with after-market firmware.

Usually SOHO router only needs to know about 2 networks anyway. The local area network (LAN) and the Internet. When the Internet connection is up it will already have the Internet network route. This is usually the 0.0.0.0 route or the Default Gateway. Cisco has Gateway of Last Resort www.cisco.com/warp/public/105/default.html#route0.0

Default gateway is all you need to get to "all other" networks in the Internet. The router will basically consider "if it isn't local" then it goes to the Default Gateway. It is assumed the Default Gateway knows what to do with packets sent for all other networks.

Now if you want to have more than one Local Area Networks that's another game. Most SOHO routers don't do that easily but it is quite possible. The "normal" way as others have mentioned is for the router to have more than one physical interface with multiple Local Area type interfaces connected to seperate physical local networks. Then you end up with quite an adventurous SOHO router. Most don't have that many interfaces. And cannot have them added. You could teach it to handle more than one local area network by programming it for that. You might want an after-market firmware to do that. Cisco routers of the SOHO type usually won't have any problem being configured for that.