Shared address space used by ISPs for carrier-grade NAT. Not routable on the public internet; allows providers to run large NAT pools without colliding with private RFC 1918 space.
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. 100.100.100.0/30 is a sub-block of 100.64.0.0/10, the defining reserved range.
All 4 IP addresses in 100.100.100.0/30
BGP Routing
Live BGP anomalies →This block is announced in BGP, observed across our RIPE RIS collectors.
Frequently Asked Questions
What is 100.100.100.0/30?
100.100.100.0/30 falls inside 100.64.0.0/10 — a Carrier-grade NAT (CGN) range reserved by RFC 6598. Shared address space used by ISPs for carrier-grade NAT. Not routable on the public internet; allows providers to run large NAT pools without colliding with private RFC 1918 space.
Is 100.100.100.0/30 routable on the public internet?
No. 100.100.100.0/30 is part of IANA-reserved special-use space (100.64.0.0/10, RFC 6598). Packets with these addresses are either filtered by backbone routers or handled as local/special traffic — they never reach the public internet.
Who owns 100.100.100.0/30?
100.100.100.0/30 is not allocated to any organization or ISP. It is part of the Carrier-grade NAT (CGN) block reserved by IANA under RFC 6598 for every network to use privately.
