IANA IPv4 Address Space Allocation for Prefix 172/8
Administered by ARIN
LEGACY - allocated by the central Internet Registry (IR) prior to the Regional Internet Registries (RIRs). This address space is now administered by individual RIRs as noted, including maintenance of WHOIS Directory and reverse DNS records. Assignments from these blocks are distributed globally on a regional basis.
- 172.16.0.0/12 reserved for Private-Use Networks [RFC1918]. Complete registration details are found in [IANA registry iana-ipv4-special-registry].