AS27321 Internet Systems Consortium, Inc.

ISC-F-AS - Internet Systems Consortium, Inc. · registered in the United States

IPv4 addresses2,0486 prefixes · <0.001% of announced IPv4

Rank in United States#6,097largest network in US by IPv4 space, of 18,338 · <0.01% of US

Rank worldwide#22,647of 79,396 networks with IPv4

IPv61 x /481 prefixes

CountryUnited States18,679 ASNs registered there

Open AS27321 in ASN lookup Look up an IP in this network (149.20.0.1) All networks in United States

IPv4 prefixes

All 6 prefixes, in address order.

149.20.0.0/24
149.20.2.0/23
149.20.4.0/24
149.20.57.0/24
149.20.66.0/24
192.158.248.0/23

IPv6 prefixes

All 1 prefix.

2001:500:6b::/48

Other ASNs named Internet Systems Consortium, Inc.

6 other networks use the same organisation name; together with AS27321 they announce 37,120 IPv4 addresses.

ASNNameIPv4 addresses

AS1280ISC-AS-1280 - Internet Systems Consortium, Inc. US23,296

AS30133ISC-F-AS - Internet Systems Consortium, Inc. US9,984

AS30132ISC-F-AS - Internet Systems Consortium, Inc. US768

AS3557ISC-AS - Internet Systems Consortium, Inc. US512

AS33071ISC-F-AS - Internet Systems Consortium, Inc. US256

AS23713ISC-SEL1 - Internet Systems Consortium, Inc. KR256

Similar-sized networks in United States

ASNNameIPv4 addresses

AS8046#6094 NAPANET - NapaNet2,048

AS14145#6095 REGIONS-ASN-3 - REGIONS FINANCIAL CORPORATION2,048

AS26716#6096 NETCRACKER - NetCracker Technology, Corporation2,048

AS27500#6098 ICANN-MEETINGS - ICANN2,048

AS29906#6099 WESTAT-AS1 - Westat, Inc.2,048

AS30006#6100 TOP-BUSINESS-INC - TOP BUSINESS INC2,048

IP-to-ASN data: iptoasn.com (public domain). Snapshot downloaded 2026-11-11, refreshed daily. Ranges are what each network announces in BGP, not registry allocations. Data sources