Same as what Mr. Bungle said: if all you are doing with 3 routers is merely to extend the wireless signal to the whole house, you better off with dedicated wireless extenders.
The 3 routers setup you described is usually use for splitting a network into 2 separate networks. For that case you need to assign all 3 with different IPs and DHCP IP ranges, to avoid conflicts and to keep them separate.
If you want to use 3 routers to extend the network by wire, you need to:
1. Set each router with a different IP in the same subnet (e.g. 192.168.1.1 / 2 / 3)
2. Use the main router (connected directly to the modem) as the only DHCP server.
3. Disable DHCP on the other 2 routers and connect them by wire to the main router, LAN port to LAN port. (Basically turning the routers into access points.)
4. Setup different wireless SSIDs for the 2 extending routers. Very important step, if they have the same SSID they may conflict with each other. If you use the wireless from the main router as well, then you need to have 3 SSIDs in the house.
5.Only connect your computer(s) to the closest router, either by wire or by using that router's wireless SSID.
If you want to use 3 routers to extend the network wirelessly, you need to:
A. Do the same as 1) and 2) above as for "by wire"
B. All 3 routers MUST have wireless repeater capability, with one of them able to act as the WDS host to the other two. Otherwise, you can't do this!
C. Setup the 2 extending routers as wireless repeater bridge to the main router. Consult with your routers' manuals for instructions on this, since different routers may have different procedures for setting this up.
D. If all goes well, the 3 routers would be bridged together wirelessly and all share the same SSID. So you can use 1 SSID throughout the whole house.
As you can see it's not that straight forward and may be confusing for someone not savvy with networking. Also, basically you are making some of the routers dumber, and not using its routing capability. If you just want a plug-and-play solution, you better off with dedicated device(s) designed for the sole purpose of extending wireless network.
The 3 routers setup you described is usually use for splitting a network into 2 separate networks. For that case you need to assign all 3 with different IPs and DHCP IP ranges, to avoid conflicts and to keep them separate.
If you want to use 3 routers to extend the network by wire, you need to:
1. Set each router with a different IP in the same subnet (e.g. 192.168.1.1 / 2 / 3)
2. Use the main router (connected directly to the modem) as the only DHCP server.
3. Disable DHCP on the other 2 routers and connect them by wire to the main router, LAN port to LAN port. (Basically turning the routers into access points.)
4. Setup different wireless SSIDs for the 2 extending routers. Very important step, if they have the same SSID they may conflict with each other. If you use the wireless from the main router as well, then you need to have 3 SSIDs in the house.
5.Only connect your computer(s) to the closest router, either by wire or by using that router's wireless SSID.
If you want to use 3 routers to extend the network wirelessly, you need to:
A. Do the same as 1) and 2) above as for "by wire"
B. All 3 routers MUST have wireless repeater capability, with one of them able to act as the WDS host to the other two. Otherwise, you can't do this!
C. Setup the 2 extending routers as wireless repeater bridge to the main router. Consult with your routers' manuals for instructions on this, since different routers may have different procedures for setting this up.
D. If all goes well, the 3 routers would be bridged together wirelessly and all share the same SSID. So you can use 1 SSID throughout the whole house.
As you can see it's not that straight forward and may be confusing for someone not savvy with networking. Also, basically you are making some of the routers dumber, and not using its routing capability. If you just want a plug-and-play solution, you better off with dedicated device(s) designed for the sole purpose of extending wireless network.
