sitelocal

Sitelocal is a term used in computer networking and IT to describe addresses or resources that are intended only for use within a single site or organization and are not meant to be reachable from the wider Internet. The concept is closely linked to private addressing and internal networks, allowing an organization to manage address space without external routability.

In IPv4, the historical concept of site-local addresses referred to blocks reserved for internal use within a site. These addresses were considered non-routable across the public Internet, enabling private networks to function without consuming global address space. Over time, the private addressing framework defined in RFC 1918 became the standard for internal networks, with widely used ranges such as 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. In practice, the explicit term site-local has largely been superseded by these private address spaces.

In IPv6, a site-local addressing scheme existed as fec0::/10 intended for local communications within a site. It encountered problems in multi-site scenarios and was deprecated in favor of other local-scoped addresses, specifically Unique Local Addresses (ULA) with the fc00::/7 prefix, as well as link-local addresses for single-segment communication. Contemporary IPv6 deployments do not rely on site-local addresses.

Today, the term "site-local" is mostly of historical interest, used mainly in discussions of IPv4 private networks and the evolution of IPv6 addressing. In current standards, internal addressing is implemented through private address spaces, local or link-local scopes, and, in some cases, network policies to control access. See also private address, NAT, and Unique Local Addresses.