|Why do you think you need to do that ? |
The two routers can't have the same URL (192.168.xxx.xxx) to access their configuration - if they do, you have to change the URL of one of them.
Have you tried connecting a computer to a port in each router ?
If you're using a high speed cable modem, I would think you should be able to connect to the internet on all available ports on the routers other than WAN , in theory ??. You should be able to connect to the internet through available ports in the network switch, but they won't have hardware firewall protection. A cable modem connection usually requires you register the wired adapter MAC address of the modem, or a serial number of the modem, with the ISP, so anything that connects to the modem directly or indirectly should be able to connect to the internet. However, you may have problems if you use the NAT features of the two router's configuration.
If you're using a DSL or ADSL connection, some of the ISPs require you register the wired adapter MAC address of your router or the wired network adapter on your computer with them. That's done by the installation software the ISP provides, or sometimes you can go to one specific URL to do that, even when you can't access the internet otherwise..
In that case...
- you can clone one computer's network adapter address when it's the only one connected, or type in one, in the router's configuration, but sometimes only one MAC address is allowed, and no two networked devices can use the same MAC address. Even if two MAC addresses are allowed, both routers can't connect to the modem and the ISP at the same time
- you wouldn't be able to connect computers to the available network switch ports to connect to the internet
What will work for sure - all or nearly all the available ports will work to connect to the internet and have the protection of one router's hardware firewall settings ...
- connect the modem to one router's WAN port, connect the network switch to the same router's port other than WAN
- connect the modem to one router's WAN port, connect the network switch to the same router's port other than WAN, connect the other router to either a port on the network switch or to a port other than the WAN port on the first router.
The two routers can't have the same URL (192.168.xxx.xxx) to access their configuration - if they do, you have to change the URL. of one of them.
The second router has to have it's DHCP disabled - that essentially makes it a switch - it then no longer uses hardware firewall features. You may not be able to use the WAN port on that second router to connect a computer to.
You may need to change the default range of addresses the second router can assign to devices connected to it.
Recent or fairly recent network switches and routers will usually auto detect whether the network cable is straight through wired or cross wired and the connection will work with either type of cable, but in any case, if the led for the port lights up, it's connecting.