Define IP address, subnet mask and default gateway.

These three settings together allow a computer to communicate inside its own network and on the internet. They are seen in ipconfig output and router setup.

1. IP Address — identity of device: An IP address is a unique numerical label given to every device on a network. Example IPv4: 192.168.1.10. Without it, data does not know where to go — like a house without address. IPv4 is 32-bit (4.3 billion addresses), IPv6 is 128-bit for future need.

2. Subnet Mask — separates network vs host part: Subnet mask tells which portion of IP is network ID and which is device (host) ID. Example: 255.255.255.0 means first 3 parts (192.168.1) = network, last part (.10) = device. Two computers with same network part can talk directly; different network part needs router. It also allows dividing one large network into small subnets for offices.

3. Default Gateway — door to other networks: Default gateway is the IP of the router that connects your local network to other networks/internet. Example: your PC is 192.168.1.10, gateway is 192.168.1.1 (router). When you open google.com (outside network), your PC sends packets to the gateway, and the gateway forwards them to the internet.

Together in one line: IP = who am I, Mask = who is in my group, Gateway = how do I go outside. In Nepal offices, wrong gateway is the most common reason “internet connected but no browsing”.