Sisäosoite

Sisäosoite, often translated as internal address or private address, refers to a numerical label assigned to a device connected to a computer network. Unlike public or external IP addresses which are routable across the internet, internal IP addresses are used for communication within a private network, such as a home or office local area network (LAN). These addresses are typically assigned by a router using a Dynamic Host Configuration Protocol (DHCP) server.

The primary purpose of internal IP addresses is to enable devices on the same network to communicate with each other without needing a unique, globally addressable IP. This conserves the limited pool of public IPv4 addresses. When a device with an internal IP address needs to access the internet, the router acts as an intermediary. It uses Network Address Translation (NAT) to map the internal IP address to its own public IP address, allowing the request to reach the external network and the response to be returned to the correct device.

Common ranges for internal IP addresses are defined by RFC 1918. These include the 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 address blocks. Any IP address falling within these ranges is considered a private IP address. Devices with these addresses cannot be directly accessed from the internet. If direct external access is required, port forwarding or other network configuration techniques are necessary, which involve directing incoming traffic from a public IP and specific port to a particular internal IP and port.