Autonomous system
AS3557 ISC-AS
Unclassified ARIN
Summary
Internet Systems Consortium (ISC)
enterprise research legacy
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. Source, and how to suggest an edit.
Interconnection
Peering at a glance
Internet exchanges
No exchange port on file. Many exchanges publish no participant list, so this is not proof of absence.
Transit providers
7 upstream, 0 downstream and 11 adjacent networks observed; most-used upstreams first.
Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-19, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 1 prefixes · 512 addresses IPv6 1 prefixes
| Country | Name | Prefixes |
|---|---|---|
| US | United States of America | 2 |
Registry
Allocation record
- Registry
- ARIN
- Handle
AS3557- Registry name
- ISC-AS
- Registrant
- Internet Systems Consortium, Inc.
- Abuse contact
- abuse@isc.org
- Registered
- 1994-04-21
- Last changed
- 2012-04-02
- Allocation
- assigned
Routing security
RPKI and IRR
- RPKI
- 100% valid · 4 valid, 0 with no ROA
- ROAs
- 2 authorising AS3557
- ASPA
- no ASPA record
- IRR
- 100% registered · 4 of 4 announcements
- Route objects
- 12 naming AS3557
Reputation
Classification and threat
Unclassified Not in the curated lists. Most of the ~80,000 allocated ASNs are not.
Spamhaus DROP
Not on ASN-DROP The network as a whole is not listed.
No DROP prefixes None of its announced space is on the DROP prefix list.
Spamhaus DROP ("Don't Route Or Peer") lists space and networks run by, or hijacked for, spam and cybercrime operations: 442 networks and 1,783 prefixes, as published 2026-10-20. A short, high-confidence list, so a match is worth taking seriously, and absence from it says little on its own.
FBI IC3
No IC3 indicators Nothing from the FBI IC3 feed.
IC3 threat data is alpha. Absence of an indicator is not evidence of good behaviour, only of absence from this one feed.
Elsewhere