http//192.168.100.1 is a private IP address which come along with certain credential. Keep this credential in the future for accessing the default gateway network. Suppose if you forget your admin password or login id and whenever you have to change the setting of your router this can be possible only through accessing that 192.168.100.1 IP address. This process is called a default gateway IP. The process of accessing that IP 192.168.100.1 address is easy and it is similar to getting inside the master settings of any device. You must have to enter the important credentials.