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Autonomous System

AS3527

National Institutes of Health

Announced IPs
331,520
CIDR prefixes
61
ASN
AS3527

Reputation · trust score

A transparent 0–100 signal. Every entity starts at a neutral baseline of 65; threat-intel blocklists, exposure, reverse-DNS, routing and allocation each adjust it up or down. Higher is more trustworthy.

59/100
Caution
How this score is built

Experimental · trust-vectors model v1.1.0 — a transparent heuristic, not a definitive verdict. How it works →

⚠ 1 MOAS prefix — multiple origin ASNs detected

All MOAS anomalies →

A previously stable prefix originated by AS3527 is now also announced by another ASN (MOAS — Multiple-Origin AS), detected from our RIPE RIS collectors. Often benign (anycast, multi-homing, or a recent transfer) — but it can signal a route leak or prefix hijack, so it's worth inspecting.

PrefixOrigin ASNsLast detected (UTC)
165.112.0.0/21 AS3527, AS30387 2026-07-23 09:38:28

Network profile

Source: PeeringDB →
Geographic scope Not Disclosed
Traffic ratio Not Disclosed

AS3527 — global IP footprint

Cities where AS3527 has measurable IPv4 allocation. Click any dot to open that city's page. Size and color scale with IP count.

View on 3D globe →

Top CIDR ranges

CIDRIPsPTR DensityOrganizationCountryStateCity
128.231.0.0/16 65.5K
0.1%
National Institutes of Health US Maryland Silver Spring
137.187.0.0/16 65.5K
0.1%
National Institutes of Health US District of Columbia Washington
157.98.0.0/16 65.5K
0.0%
National Institutes of Health US North Carolina Chapel Hill
156.40.128.0/18 16.4K
0.1%
National Institutes of Health US District of Columbia Washington
165.112.64.0/18 16.4K
0.0%
National Institutes of Health US Virginia Leesburg
156.40.0.0/19 8.2K
0.1%
National Institutes of Health US Maryland Bethesda
156.40.224.0/19 8.2K
0.0%
National Institutes of Health US Maryland Bethesda
162.99.224.0/19 8.2K
0.0%
National Institutes of Health US Maryland Derwood
165.112.64.0/19 8.2K
0.0%
National Institutes of Health US Virginia Leesburg
165.112.160.0/19 8.2K
0.0%
National Institutes of Health US
165.112.224.0/19 8.2K
0.0%
National Institutes of Health US Arizona Phoenix
156.40.32.0/20 4.1K
0.0%
National Institutes of Health US
156.40.64.0/20 4.1K
0.0%
National Institutes of Health US
156.40.112.0/20 4.1K
0.1%
National Institutes of Health US
156.40.208.0/20 4.1K
0.2%
National Institutes of Health US Maryland Silver Spring
156.40.224.0/20 4.1K
0.0%
National Institutes of Health US Maryland Bethesda
165.112.16.0/20 4.1K
0.0%
National Institutes of Health US Maryland Bethesda
165.112.48.0/20 4.1K
0.0%
National Institutes of Health US District of Columbia Washington
165.112.96.0/20 4.1K
0.0%
National Institutes of Health US Maryland Rockville
165.112.144.0/20 4.1K
0.0%
National Institutes of Health US
165.112.208.0/20 4.1K
0.0%
National Institutes of Health US
165.112.224.0/20 4.1K
0.0%
National Institutes of Health US
156.40.56.0/21 2.0K
0.0%
National Institutes of Health US
156.40.80.0/21 2.0K
0.0%
National Institutes of Health US
156.40.104.0/21 2.0K
0.1%
National Institutes of Health US
156.40.200.0/21 2.0K
0.0%
National Institutes of Health US
156.40.248.0/21 2.0K
0.0%
National Institutes of Health US
165.112.40.0/21 2.0K
0.1%
National Institutes of Health US
165.112.112.0/21 2.0K
0.0%
National Institutes of Health US
165.112.128.0/21 2.0K
0.0%
National Institutes of Health US
165.112.200.0/21 2.0K
0.0%
National Institutes of Health US
165.112.240.0/21 2.0K
0.0%
National Institutes of Health US
156.40.48.0/22 1.0K
0.0%
National Institutes of Health US
156.40.88.0/22 1.0K
0.0%
National Institutes of Health US
156.40.100.0/22 1.0K
0.0%
National Institutes of Health US
156.40.192.0/22 1.0K
0.8%
National Institutes of Health US
156.40.240.0/22 1.0K
0.0%
National Institutes of Health US
165.112.0.0/22 1.0K
0.0%
National Institutes of Health US
165.112.12.0/22 1.0K
0.0%
National Institutes of Health US
165.112.36.0/22 1.0K
0.0%
National Institutes of Health US
165.112.120.0/22 1.0K
0.0%
National Institutes of Health US
165.112.136.0/22 1.0K
0.0%
National Institutes of Health US
165.112.196.0/22 1.0K
0.0%
National Institutes of Health US
165.112.204.0/22 1.0K
0.0%
National Institutes of Health US
165.112.248.0/22 1.0K
0.0%
National Institutes of Health US
156.40.54.0/23 512
0.0%
National Institutes of Health US
156.40.96.0/23 512
0.0%
National Institutes of Health US
156.40.198.0/23 512
0.0%
National Institutes of Health US
156.40.244.0/23 512
0.0%
National Institutes of Health US
165.112.4.0/23 512
0.0%
National Institutes of Health US
165.112.142.0/23 512
0.0%
National Institutes of Health US
165.112.192.0/23 512
0.0%
National Institutes of Health US
165.112.254.0/23 512
0.0%
National Institutes of Health US
192.231.146.0/23 512
1.4%
National Institutes of Health US Maryland Rockville
156.40.52.0/24 256
0.0%
National Institutes of Health US
156.40.92.0/24 256
0.0%
National Institutes of Health US
156.40.196.0/24 256
0.0%
National Institutes of Health US
156.40.247.0/24 256
0.0%
National Institutes of Health US
165.112.126.0/24 256
0.0%
National Institutes of Health US
165.112.141.0/24 256
0.0%
National Institutes of Health US
192.231.145.0/24 256
4.7%
National Institutes of Health US

BGP Announced Prefixes

Live BGP anomalies →

Prefixes AS3527 actually originates in BGP, observed across our RIPE RIS collectors. This live routing view can differ from the registry allocation above.

PrefixAnnouncement samplesLast seen
192.231.146.0/24 7,090 2026-07-23 15:47:17
192.231.146.0/23 4,896 2026-07-23 15:47:12
128.231.0.0/16 3,489 2026-07-23 15:47:17
137.187.0.0/16 3,488 2026-07-23 15:47:17
165.112.0.0/16 3,487 2026-07-23 15:47:17
192.231.147.0/24 3,480 2026-07-23 15:47:17
157.98.0.0/16 3,421 2026-07-23 15:47:17
162.99.224.0/19 3,420 2026-07-23 15:47:17
156.40.0.0/16 3,411 2026-07-23 15:47:17
128.231.245.0/24 3,384 2026-07-23 15:47:17
128.231.3.0/24 3,316 2026-07-23 15:47:17
192.231.145.0/24 3,304 2026-07-23 15:47:39
165.112.136.0/21 79 2026-07-23 09:35:44
165.112.0.0/20 78 2026-07-23 09:35:44
165.112.0.0/21 78 2026-07-23 09:35:44

Frequently Asked Questions

What is AS3527?

AS3527 is an Autonomous System Number assigned to National Institutes of Health. An ASN identifies a network that controls a specific set of IP addresses and determines how traffic is routed across the internet via BGP (Border Gateway Protocol).

How many IP addresses does AS3527 announce?

AS3527 announces 331.5K IPv4 addresses distributed across 61 routed CIDR prefixes. The network is registered in United States.

Who operates AS3527?

AS3527 is operated by National Institutes of Health. The organization is based in United States. You can view all IP ranges and related ASNs on the organization page.

What country is AS3527 registered in?

AS3527 is registered in United States. This indicates where the network operator is headquartered, though the IP addresses it announces may serve users globally.

Last updated: 2026-07-23 15:55:31 UTC
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