ISPs often install the cable/dsl modem by connecting it directly to a single client computer to eliminate having to setup local area networks and deal with routers.
Connecting a wireless/wired router between your modem and your clients is not hard, but may require some basic networking knowledge. I'll try to outline some of the main points to keep in mind below:
1. Connect your router between the modem and your client PC(s) - NAT routers should have one external port labeled "WAN" or "Internet" for connecting to the modem, and several "LAN" local Ethernet ports for connecting client devices. Make sure you connect the modem to the WAN port, and clients to the LAN ports. It may be a good idea to have the devices powered down while connecting them.
2. Power cycle the cable/dsl modem every time you connect a new device to it - this is needed not only for safety, but also for the modem to be able to recognize and use the new MAC address for the router or device connected to it.
3. Power cycle the router after the cable/dsl modem - the router needs to obtain its new WAN/Internet IP address from the cable/dsl modem. Most routers are set to obtain an IP automatically via DHCP by default. For some PPPoE dsl connections, you may have to login to the router's admin interface and setup the WAN connection type to PPPoE, and add your username/password.
4. Disable/Enable your network adapter to obtain a new IP from the router - most routers are set to serve internal IPs via DHCP, and your client should obtain one automatically. At this point, you will either get:
- Internet access (if the router was able to connect to the modem, and your client is connected to the router)
- Only local network access (if your computer is only connected to the router, however the router is not connected to the modem/internet properly. In this case you will have to reconfigure the router via its admin interface)
- limited/no network connectivity (this means the router is not set to serve IPs automatically, you will have to manually set your network adapter to a static IP in the router's subnet/range so you can configure your router)
5. Setup your router - routers have a default IP address where you can connect via web browser to set them up. You can find the address for your model in our hardware database, or read the manual. Connect to your router, choose whether you want it to serve internal IPs automatically (act as a DHCP server), configure UPnP, DMZ, static IPs, port forwarding, etc.
6. Secure your wireless router - most routers have known default passwords, and their wireless signal is unsecure by default for easier setup. Don't forget to secure your network.
Notes: In some rare cases, the cable/dsl modem may be bound to the MAC address of a single device/computer. In such cases (if rebooting the cable modem does not connect it to the new device), you will have to find the MAC address of that bound device/network adapter, and then "clone" it in the router's administration interface so that the router appears to be that device. Most routers support MAC address cloning.
