Free ASN Lookup: Find an IP's Network Operator Instantly
What is an ASN lookup?
An autonomous system is a network on the public internet operated as a single unit, with a single routing policy. ISPs, hosting providers, cloud platforms, and large enterprises each operate one or more, and each one is identified by a unique Autonomous System Number (ASN). Google operates AS15169. Cloudflare is AS13335. Amazon Web Services spans dozens, anchored by AS16509.
An ASN lookup takes an IP address and returns:
- The ASN itself (for example, AS15169)
- The organization name registered for that ASN (Google LLC, Cloudflare, Inc., Amazon.com, Inc.)
- The ASN type: business, ISP, hosting, education, or government
The lookup goes one direction only: IP to ASN. It does not return the full list of IP ranges an ASN announces to the global routing table; that is a different lookup served by BGP routing tools.
How ASN lookup works
When you submit an IP address, the lookup runs three steps:
- Input parsing: The IP is parsed and validated as IPv4 or IPv6. Both address families are supported.
- BGP cross-reference: The IP is mapped to the autonomous system currently announcing the block that contains it, using current routing-table data. This is the same source the global routing layer uses, not a stale registry record.
- Response enrichment: The result includes the ASN, organization name, ASN type, and geographic context (country, region, city) plus a hosting flag, in one response.
ASN data refreshes continuously from BGP route announcements published by the network operators themselves, so the result reflects the network currently announcing each IP. Most cases complete in under 200ms.
IP-to-ASN vs. ASN-to-IP-ranges
Both questions involve ASN data but go in opposite directions, and they are answered by different tools.
IP-to-ASN lookup (what this tool does) takes an IP and returns the autonomous system that owns the block containing it. The standard direction for traffic attribution, log enrichment, abuse research, and any decision that keys off who is operating the network behind a given IP.
ASN-to-IP-ranges goes the other way: paste an ASN and get back every CIDR block that ASN announces to the global routing table. Useful for building network-wide allow or deny lists, scoping research to a specific operator, or BGP routing analysis. This direction is not offered by Abstract. BGP.he.net (Hurricane Electric) and RIPEstat are free, well-maintained, and built for that workflow.
Use this tool when you have an IP and want to know which network operates it. Use BGP.he.net or RIPEstat when you have an ASN and want to enumerate its IP space.
Use cases for ASN lookup
Network and security debugging: Investigate suspicious traffic in your logs. Get the ASN, organization, and ASN type for any IP in your incident timeline. A request from AS15169 (Google) reads very differently from one out of a residential ISP or a small hosting ASN with abuse history.
Traffic attribution and analytics: Group inbound traffic by network operator instead of by raw IP. See how much of your API traffic comes from AWS, GCP, and Azure versus residential ISPs. Useful for capacity planning, rate-limit tuning, and abuse-pattern detection.
Hosting and cloud detection: Detect requests originating from datacenters and cloud providers. ASN type "hosting" is a strong signal that a request is not a typical end user. Combine with the abuse and proxy fields for sharper rules.
Abuse reporting and take-downs: When you need to report an IP, you need the operator's contact path. The ASN identifies the network responsible, which is the starting point for filing an abuse report with the right party rather than guessing.
See what the API returns
Response parameters
ip_address
security.is_vpn
security.is_proxy
security.is_tor
security.is_hosting
security.is_relay
security.is_mobile
security.is_abuse
asn.asn
asn.name
asn.domain
asn.type
company.name
company.domain
company.type
domains.domains
location.city
location.city_geoname_id
location.region
location.region_iso_code
location.region_geoname_id
location.postal_code
location.country
location.country_code
location.country_geoname_id
location.is_country_eu
location.continent
location.continent_code
location.continent_geoname_id
location.longitude
location.latitude
timezone.name
timezone.abbreviation
timezone.utc_offset
timezone.local_time
timezone.is_dst
flag.emoji
flag.unicode
flag.png
flag.svg
currency.name
currency.code
currency.symbol
API Endpoint
curl --request GET \
--url https://ip-intelligence.abstractapi.com/v1API Response
{
"ip_address": "185.197.192.65",
"security": {
"is_vpn": true,
"is_proxy": true,
"is_tor": false,
"is_hosting": false,
"is_relay": false,
"is_mobile": false,
"is_abuse": false,
},
"asn": {
"asn": 136787,
"name": "PacketHub S.A.",
"domain": "packethub.tech",
"type": "isp",
},
"company": {
"name": "PacketHub S.A.",
"domain": "packethub.tech",
"type": "isp",
},
"domains": {
"domains": []
},
"location": {
"city": "Miami",
"city_geoname_id": 4164138,
"region": "Florida",
"region_iso_code": "FL",
"region_geoname_id": 4155751,
"postal_code": "33197",
"country": "United States",
"country_code": "US",
"country_geoname_id": 6252001,
"is_country_eu": false,
"continent": "North America",
"continent_code": "NA",
"continent_geoname_id": 6255149,
"longitude": -80.1946,
"latitude": 25.7689,
},
"timezone": {
"name": "America/New_York",
"abbreviation": "EST",
"utc_offset": -5,
"local_time": "12:07:51",
"is_dst": false,
},
"flag": {
"emoji": "🇺🇸",
"unicode": "U+1F1FA U+1F1F8",
"png": "https://static.abstractapi.com/country-flags/US_flag.png",
"svg": "https://static.abstractapi.com/country-flags/US_flag.svg",
},
"currency": {
"name": "US Dollar",
"code": "USD",
"symbol": "$"
}
}ASN Lookup FAQ
What is an ASN?
An Autonomous System Number (ASN) is a unique identifier assigned to a network on the public internet. Internet Service Providers, hosting and cloud providers, and large organizations each operate one or more autonomous systems, and each one has an ASN. ASNs are how routers on the internet decide where to send traffic. Google's network is AS15169, Cloudflare's is AS13335, Amazon Web Services has dozens spanning AS16509 and others.
What is an ASN lookup?
An ASN lookup takes an IP address and returns the autonomous system that owns the IP block it belongs to. The result includes the ASN number (for example, AS15169), the organization name (Google LLC), and the ASN type (business, isp, hosting, education, government). Abstract returns this in under 200ms.
How is ASN lookup different from WHOIS?
WHOIS returns the legal registrant of an IP block (the entity that paid the regional registry for it), which is often outdated, sometimes shielded, and may differ from who actually operates the network. ASN data reflects the network operator currently announcing the IP block to the global routing table, which is closer to the question most people are actually asking: who is sending or receiving this traffic?
Can I look up an ASN to find all the IP ranges it owns?
Not with this tool. Abstract's ASN lookup goes IP to ASN: paste an IP, get the ASN. The reverse direction (paste an ASN, get all the CIDR ranges it announces) is a different lookup served by BGP routing tools. BGP.he.net (Hurricane Electric) and RIPEstat are good free resources for that.
How accurate is the ASN data?
ASN data is highly accurate because it comes from the same source the global routing table uses: BGP route announcements published by the network operators themselves. Abstract refreshes the underlying ASN-to-IP-block mappings on a continuous basis, so the result reflects the network currently announcing each IP, not a stale snapshot.
Is the ASN Lookup tool free?
Yes. The online tool is free with no signup required for individual lookups. For programmatic access, Abstract's IP Intelligence API offers a free tier with 1,000 requests per month. View pricing for higher-volume plans.
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