IPv4 private addressing refers to a range of IP addresses reserved for use within private networks. These addresses are not routable on the public internet, meaning routers on the internet will not forward packets destined for these addresses. Instead, they are intended for use within local area networks (LANs) or for internal communication within organizations.

The Internet Assigned Numbers Authority (IANA) has reserved three blocks of IP addresses for private networks, as defined in RFC 1918:

1. 10.0.0.0 – 10.255.255.255 (a single Class A network)
2. 172.16.0.0 – 172.31.255.255 (16 contiguous Class B networks)
3. 192.168.0.0 – 192.168.255.255 (256 contiguous Class C networks)

These ranges provide a significant number of addresses for use in private networks, allowing for the creation of large networks without the need for public IP addresses for each device.

Private addressing is commonly used in home and business networks where multiple devices need to communicate with each other but do not need direct access to the internet. Network Address Translation (NAT) is often used in conjunction with private addressing to allow devices with private addresses to access the internet indirectly through a router that has a public IP address.

Private addressing helps conserve public IP address space by allowing many devices to share a single public IP address for internet communication, reducing the demand for public IP addresses.