September 22, 2023 Network security: How do I change my router/modem password?

Modem-routers have a tiny web server inside them, you can connect to that (like any other web server, using a web browser), and change the settings. Indeed, this is where the danger is – if the modem/router has default settings, potentially anyone can log in to it, and see everything you do on the internet! Changing the admin password for this device is a two step process; first we find out how to connect to the modem/router by its IP address, then we log in to change the admin password.

Finding the modem/router IP address, for Windows

1. Start menu, type “command”, run the “command prompt” program
2. Type, “ipconfig”, press enter
3. Look for the “Default Gateway” IP address
4. Write this down
5. Type “exit” to close the window

ABOVE: Finding gateway IP in Windows. (1) Issuing the command “ipconfig” (2) “Default Gateway” section (3) The IP address we need, highlit in yellow.

Finding the modem/router IP address, for MacOS

1. Click the Apple icon (at the top left of the screen) and select System Preferences.
2. Click Network.
3. Select your network connection and then click Advanced.
4. Select the TCP/IP tab and find your gateway IP address listed next to Router.

Finding existing modem/router password

Now we know the IP address, we know how to find the modem/router… but how do we log in? There are a few ways:

• The modem/router might use a default username and password, like “admin” and “admin”, or “admin” and “password”
• You could search online for that modem/router brand and model number, to see what the default setting is
• The modem/router might have a sticker on it that says what the router login details are (see example below). The sticker might be on the back, side or bottom of the device – might be easiest to take a pic of it with your smartphone!
• The manual that came with the modem/router might have this information
• Your ISP can provide this information

Once known, write this down, it’s needed in the next step.

ABOVE: an example router/modem sticker. It has wifi network names and passwords, and below the second barcode, router login details – that’s what we need!

Changing the modem/router password

1. Visit the IP address for the Gateway (Router) as found in the previous step
2. Enter the existing username and password, as found in the previous step
3. Change the admin password
   1. Every modem/router is a little different. Look in the menu for “admin settings”, “management”, “access control” or similar
   2. Set a strong and complex password, it does not need to be memorable. Use https://passwordsgenerator.net/, at least 16 characters
   3. The router may reboot after changing the password, meaning no internet for a few minutes 😱
4. Record the new password
   1. Add it to your personal password manager (while you can add it to your work LastPass account, that’s not ideal we do not need to know it)
   2. Add the modem/router’s IP address to the record as well, and name it “Home modem/router” or something useful
5. Bask in the nerdy feeling of being more secure 🙂