Follow these simple steps to log into your Router with a 192.168.178.21 ip address.
Connect router cable to your computer. (You can also use a wireless network). Double-check the device that you wish work on is connected to the wi-fi.
Pro Tip - It's a good idea to use a wired connection while making any changes. This avoids the risk of suddenly being logged off when you click the Save button.
Open your chosen web browser and type the router's IP address in the address bar. You can find it on the back of your router packaging. If the address fails, you'll need to grab your router manual. The IP listed as Default Gateway is the correct one.
It's time to enter the default username and password of your router by accessing the admin panel. You can try the login credentials given below. The default values for admin are:
root | user | admin
If none of the above are successful, type your router’s name into your browser to locate the default login username and password you need. You should be directed to the models' configuration page where the network and the router settings can be managed.
If you can’t log in to your router, then you are probably entering the wrong username or password. Also, remember to make a note of both after you've changed them.