Like me, you may have a couple used routers sitting around, but they’re password protected, so you can’t do anything with them as is. Thankfully, resetting them is fairly easy. Routers are configured by opening a web-based setup page and logging in. The web page address is simply the IP address of your router. Most routers default to 192.168.1.1 when reset, but some may not.
First, plug the router into an outlet and unplug all ethernet cables. Then find the reset button, and hold it down for 30 seconds.
Step 1: Finding the Default IP Address
Next, you’ll want to check what your router’s default IP address is. One way of doing this is searching online for the default IP address of your router (use the model number and brand name to search).
If you do not have internet access, there is another option; however, I only know how to do it with Windows. First, plug in the router to an outlet, and connect it to your PC. You can do this over WiFi or an ethernet cable. Either way, make sure it is the only connection active. Then go to Control Panel > Network and Sharing Center. Under the only active connection (the router), find “Connections:” near the middle of the screen, and click the following link. Click “Details” and then find the item with “Default Gateway” in the name (See picture above). Again, for most routers, this will be 192.168.1.1.
Step 2: Logging in and Changing Settings
Now, making sure your only active connection is the router, simply go to any internet browser and enter the IP address in the search bar. It should come up with a page similar to what's shown above. The login credentials reset along with everything else, so it will be back to default. These may also be different for each brand. For example, Linksys uses no username, just "admin" in the password field, and Netgear uses "admin" for the username, and "password" for the password. If neither of these work, you'll need to search online, or it may be printed on your router somewhere.
After you log in, you'll get the setup page, which is different for each brand. Everything can be customized there.