Class E block reserved by the IETF for future use. Not currently routable on the public internet and not in general operational use.
This range is reserved by IANA — it is not allocated to an organization, ISP, or regional internet registry. Addresses here appear on every private/internal network that follows the standard, so lookups will not identify a specific owner. 251.0.0.0/8 is a sub-block of 240.0.0.0/4, the defining reserved range.
First 256 of 16,777,216 IP addresses in 251.0.0.0/8
Frequently Asked Questions
What is 251.0.0.0/8?
251.0.0.0/8 falls inside 240.0.0.0/4 — a Reserved for future use range reserved by RFC 1112. Class E block reserved by the IETF for future use. Not currently routable on the public internet and not in general operational use.
Is 251.0.0.0/8 routable on the public internet?
No. 251.0.0.0/8 is part of IANA-reserved special-use space (240.0.0.0/4, RFC 1112). Packets with these addresses are either filtered by backbone routers or handled as local/special traffic — they never reach the public internet.
Who owns 251.0.0.0/8?
251.0.0.0/8 is not allocated to any organization or ISP. It is part of the Reserved for future use block reserved by IANA under RFC 1112 for every network to use privately.
