AS3557 — ISC-AS

AS3557 announces 1 IPv4 prefixes covering 512 addresses and 1 IPv6 prefixes.

About this network

ISC-AS, the network of Internet Systems Consortium, Inc., the non-profit behind BIND, the most widely deployed DNS server software, and the operator of one of the internet's DNS root servers.

What it's used for

• Announcing the address space that carries f.root-servers.net, one of the thirteen root name servers, from ISC's globally distributed anycast nodes.
• ISC's own infrastructure and open-source project hosting.

Notable

• Only about 512 IPv4 addresses, but they are among the most queried on the internet: every DNS resolver that starts a lookup from the root may reach one of them.
• The same prefix is announced from many sites worldwide via anycast, so its geography is effectively global even though ISC is a US organisation.
• Critical infrastructure, not consumer or hosting address space.

Interesting

• ISC also develops the DHCP and Kea software many networks run, making it one of the small number of organisations whose code and whose packets both sit on the internet's critical path.

This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy.

Announced prefixes

• 192.5.4.0/23
• 2001:500:2e::/47

Upstream networks

• AS13335 Cloudflare, Inc.
• AS30132 Internet Systems Consortium, Inc.
• AS33071 Internet Systems Consortium, Inc.
• AS1280 Internet Systems Consortium, Inc.
• AS205488 Internet Systems Consortium Inc.

Adjacent networks

• AS13335 Cloudflare, Inc.
• AS30132 Internet Systems Consortium, Inc.
• AS33071 Internet Systems Consortium, Inc.
• AS1280 Internet Systems Consortium, Inc.
• AS205488 Internet Systems Consortium Inc.