Special-Purpose IP Address Registries
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M. Cotton, L. Vegoda, R. Bonica, B. Haberman · 2013-04
Abstract
RFC 6890 consolidates and clarifies the IANA registries for special-purpose IPv4 and IPv6 addresses, defining which address ranges have restricted forwarding, global routability, or other special properties. It supersedes earlier fragmented documentation of special-use addresses.
Why This RFC Matters
The internet accumulates special-purpose address ranges over decades — loopback, link-local, documentation prefixes, private ranges, multicast — and operators need a single authoritative reference for how each should be handled. RFC 6890 created that reference, consolidating into one document the routing and forwarding properties of all special-use IP address ranges for both IPv4 and IPv6. Network equipment vendors, security tools, and address validation libraries all use RFC 6890 as the canonical source for determining whether an address is globally routable, reserved, or restricted. Its structured registry format also established a template that subsequent special-purpose address RFCs follow.