What happens when I plug a router into another router?

Question

I've recently switched ISPs, and the new one provided me with a modem (that what you call those things?) that doubles as a router.

I used a router on my previous ISP for wireless networking, but I've since taken it out of the equation to simplify things.

Basically, my setup went from:

WiMax Cable -> Modem -> MyRouter -> PC/Laptop

To:

Broadband Cable -> Modem/Router -> PC/Laptop

But, there are some problems.

For one thing, my ISP forbids me from changing my router password. I'm not concerned about security, as the password is long and complex enough, but that's the problem - every time a guest comes over and asks for access I have to recite this long string from a box. I'd much rather have my own password that I change regularly.

Second, during times of questionable connectivity, I often restart the modem. And I'm pretty sure that would also take down the wireless network, right?

Finally, the modem/router's range is pretty poor. My own router can at least spread the connection beyond the house. This one can barely push it out of the room it's in.

So, I want to change my setup from above, into this:

Broadband Cable -> Modem/Router -> MyRouter -> PC/Laptop

I'll be treating the Modem/Router as a Modem and plug in to my router via LAN cable.

What I want to know is:

• Will it affect my internet connectivity / introduce latency etc., etc.
• Will it affect my network / jumble up IP addresses and make local connections more of a pain than it already is.

Thanks.

Answer 1

If you are unable to make changes to the ISP router, then I would use your own wifi router, but use it as a layer 2 device, rather than as a router.

All this means is that the devices that connect to your router are on the same network as if they were connected directly to the ISP router.

The way to do this is to disable DHCP on your router, and connect it to the ISP router using LAN ports. This is important. Your router probably has a WAN port - ignore this and connect one of the lan ports to the router LAN port.

Now anything that connects to your router will issue a DHCP request for an IP address. Your router DHCP will be disabled, and as the LAN ports are connected, the ISP router will see the DHCP request and respond.

This is far simpler than the alternative of trying route twice. I would recommend disabling the wifi on the ISP router if you can, otherwise it is just using up radio bandwidth.