ASN Lookup

Look up any autonomous system number (ASN), IP address or network name: who holds it and what kind of network it is, how many people use it, the prefixes it announces and how widely they're seen, and its providers, peers and customers.

Updated October 24, 2026

Routes: RIPE RIS, Oct 23, 2026 · relationships: CAIDA, Oct 1, 2026 · users: APNIC Labs, Oct 15, 2026 · registrations: the five RIRs

Takes AS13335, 13335, asdot 1.10, an IPv4 or IPv6 address or prefix, a domain or URL, or a name like “deutsche telekom”.

Try

What is an ASN (autonomous system number)?

An ASN (autonomous system number) is the number that identifies one network on the internet's routing map: a group of IP prefixes run by one or more operators under a single routing policy (RFC 1930). That is the ASN meaning in networking: never an advance shipping notice or a nursing degree.

Networks use it in BGP, the protocol they speak to tell each other which addresses they can reach. AS13335 is Cloudflare, AS3320 is Deutsche Telekom. Each network announces its prefixes to its neighbours, and those announcements, passed on from network to network, are how a packet for 1.1.1.1 finds Cloudflare.

Prefixes: RIPE RIS, Oct 23, 2026 · links: inferred by CAIDA from BGP paths and IXP route-server data (AS Relationships, Oct 1, 2026): Cogent is a provider of Sonic and Cloudflare; Cogent and Cloudflare both peer with Telekom · rank: CAIDA AS Rank.

How to find the ASN of an IP address (IP to ASN)

To find an IP address's ASN, take the most specific route that covers the address and read that route's origin AS. Type the address above, or ask Team Cymru's DNS: dig +short TXT 8.8.8.8.origin.asn.cymru.com (the address goes in backwards: 192.0.2.44 becomes 44.2.0.192).

Wider routes often cover the same address. 8.8.8.8 also sits inside Lumen's 8.0.0.0/9 and 8.0.0.0/12, but routers always follow the longest match, so Google's 8.8.8.0/24 decides: the address belongs to AS15169.

% dig +short TXT 8.8.8.8.origin.asn.cymru.com

The origin AS, the BGP prefix, the country, the registry and the date the block was handed out (not the AS's age).

8.8.8.8: 3 routes cover it, the longest one decides

8.0.0.0/9Lumen AS3356widerseen by 336 RIS peers

8.0.0.0/12Lumen AS3356widerseen by 335 RIS peers

8.8.8.0/24Google AS15169longest matchseen by 374 RIS peers

The most specific route wins: /24 beats /12 beats /9. Its origin:AS15169 Google

Team Cymru · recorded Oct 24, 2026

$ dig +short TXT 8.8.8.8.origin.asn.cymru.com
"15169 | 8.8.8.0/24 | US | arin | 2023-12-28"

$ whois -h whois.cymru.com " -v 8.8.8.8"
AS      | IP               | BGP Prefix          | CC | Registry | Allocated  | AS Name
15169   | 8.8.8.8          | 8.8.8.0/24          | US | arin     | 2023-12-28 | GOOGLE - Google LLC, US

the origin AS of the most specific route
that route: the BGP prefix the address falls in
the registry and the date it handed out the address block, not the AS's own date

Routes: RIPE RIS, Oct 23, 2026, 18:13 UTC (the most-seen IPv4 prefix reaches 447 peers) · answers: Team Cymru, recorded Oct 24, 2026.

Reading the result

The head says in one sentence who holds the network and what kind it is, with its mark; for an ISP, the standing beside it gives APNIC Labs' estimate of its users. The notes under it are the findings that matter, each with its source.

Overview lists the registration (from the registries' statistics and their own record, fetched by your browser) beside the routing facts. Prefixes shows every route RIPE RIS sees and how many of its peers see it, Neighbours the providers, peers and customers CAIDA infers, and Commands the same lookups for a terminal. On the right, the navy column draws the network's place in the internet.

ASN lookup of AS3320 Deutsche Telekom: a Tier 1 ISP's verdict, users, prefixes and its place among the Tier 1 networks — An ASN lookup of AS3320, Deutsche Telekom: the verdict with its standing, the registration and routing facts, and its place in the internet on the right. Select a number to see what each part shows.

ASN ranges: 16-bit, 32-bit, private and reserved numbers

AS numbers run from 0 to 4,294,967,295. The first 65,536 are the original 16-bit numbers; the rest are 32-bit numbers, added by RFC 4893 and defined today by RFC 6793. Asdot notation (RFC 5396) writes a 32-bit number as two halves: 65546 is 1.10.

Some numbers are never assigned. AS0 is reserved and may never appear in BGP (RFC 7607), AS23456 stands in for a 32-bit number on routers that only know 16-bit ones, 64496–64511 and 65536–65551 are for documentation (RFC 5398), 64512–65534 and 4200000000–4294967294 are for private use (RFC 6996), and the last number of each range is reserved (RFC 7300). Blocks IANA hasn't handed to a registry yet are unallocated.

Every AS number, 0 to 4,294,967,295

16-bit · 0 – 65,53556,532 assigned · 37,710 announce routes seen by ≥ 10 RIS peers

0reserved: may never appear in BGP; in a ROA it marks space that shouldn't be routedRFC 7607RFC 6483
112AS112: reverse-DNS sink, announced on purposeRFC 7534
23456AS_TRANS: stands in for a 32-bit number on 16-bit routersRFC 6793

enlarged: 64,496 – 65,535

64496–64511 documentationRFC 5398
64512–65534 private use: must be removed before routes reach the internet; leaks still show up in RISRFC 6996
65535 reserved: the last numberRFC 7300

32-bit · 65,536 – 4,294,967,29566,452 assigned · 48,798 announce routes seen by ≥ 10 RIS peers

65,536 – 404,380: documentation, IANA's reserve, the RIRs' 32-bit blocks and unallocated gaps, a hair at full scale

404,381 – 4,199,999,999not yet given out by IANA
4200000000 – 4294967294private useRFC 6996
4294967295reserved: the last numberRFC 7300

asdot RFC 539665546 = 1 × 65536 + 10, written 1.10· 4200000000 is 64086.59904

given to the RIRsdocumentationprivate usereservedreserved by IANAnot yet given out by IANA

Ranges: IANA: Autonomous System (AS) Numbers · Special-Purpose AS Numbers · counts: nro-delegated-stats, Oct 23, 2026 · routes: RIPE RIS, seen by ≥ 10 peers.

Who assigns AS numbers: IANA and the five RIRs

IANA hands blocks of AS numbers to the five regional internet registries, and each RIR assigns them to networks in its region: ARIN (the US, Canada and many Caribbean and North Atlantic islands), RIPE NCC (Europe, the Middle East and parts of Central Asia), APNIC (Asia-Pacific), LACNIC (Latin America and the Caribbean) and AFRINIC (Africa).

Their delegated statistics list 122,984 assigned AS numbers on October 23, 2026; 86,508 of them announce routes that at least 10 RIPE RIS peers see. Some countries add a national registry under the RIR: in APNIC's statistics every number one of them hands out shares that registry's holder ID, so numbers grouped by that ID aren't one company's.

nro-delegated-stats (the five RIRs' combined file), Oct 23, 2026 · routes: RIPE RIS, Oct 23, 2026 · land: Natural Earth in 3° dots, so borders and islands are approximate.

Upstreams, peers and customers: how ASNs connect

Networks connect in two ways: a customer pays a provider (its upstream) to carry its traffic to the rest of the internet, and peers swap traffic between their own networks and customers, usually without paying.

A path climbs from customer to provider, crosses at most one peering link and comes down again. One path along CAIDA's inferred links runs from Sonic up to Cogent, across to Deutsche Telekom and down to Wikimedia. At the top sit the Tier 1 networks, which pay no one for transit. There is no official list: CAIDA uses a fixed clique of 18 transit-free networks as the top of its inference.

Links and counts: inferred by CAIDA from BGP paths and IXP route-server data (AS Relationships, Oct 1, 2026) · the clique: the same file's input clique.

Why prefix counts differ between ASN tools

Prefix counts differ because tools count different things: every route any collector heard, only the routes most of the internet sees, or the address space that ends at the network.

Jio announces 2,116 IPv4 prefixes that RIPE RIS hears, but only 1,045 are seen by 50 or more RIS peers; for IPv6 the same network shows 4,632, 421 or 132 depending on the cut-off. Addresses differ too: Google's IPv4 prefixes add up to 4.2M addresses, overlaps collapse that to 2.6M, and only 1.4M are routed to AS15169 itself. This page names the collector and the cut-off beside every count.

Three honest answers to “how many prefixes?” and “how many addresses?”

Jio AS55836 · IPv4 prefixes

every route RIS hearsseen by ≥ 1 RIS peer2,116
the prefixes this page listsseen by ≥ 10 RIS peers2,088
seen worldwideseen by ≥ 50 RIS peers1,045

Jio AS55836 · IPv6 prefixes

every route RIS hearsseen by ≥ 1 RIS peer4,632
the prefixes this page listsseen by ≥ 10 RIS peers421
seen worldwideseen by ≥ 50 RIS peers132

Other tools say anything from 132 to 4,620 for this network (our study, Oct 23, 2026).

Google AS15169 · IPv4 addresses

prefixes added upoverlaps counted twice4,206,080
unique addresses it originatesoverlaps collapsed2,615,808
addresses routed to itthe longest match ends at AS15169 (IPtoASN)1,376,768

RIPE RIS, Oct 23, 2026: IPv4 at 18:13 UTC, IPv6 at 18:30 UTC (the most-seen prefix reaches 447 peers on IPv4, 419 on IPv6) · routed: IPtoASN, Oct 23, 2026.

How to get an ASN

To get an ASN you apply to the RIR for your region and show that you'll connect to other networks with your own routing policy. The rules differ: RIPE NCC requires multihoming, ARIN gives an organisation its first ASN on request, and APNIC, LACNIC and AFRINIC ask for a plan to interconnect with other networks.

The paperwork and the fees differ by registry and change over time, so the table lists each RIR's own policy. Most new numbers are 32-bit, and most RIRs no longer let you choose; LACNIC still assigns a 16-bit number if you justify it technically.

Where to apply, who qualifies and what it costs

RegistryWho qualifiesHow to applyWhat it costs

RIPE NCC1,895 new in 20253 of them 16-bit · 2,444 so far in 2026A multihomed network with a new, unique routing policy, written in RPSL with the request.16-bit numbers: no choice since 2010Policy: RIPE-679As a member (LIR), or as an End User through a sponsoring LIR.EUR 1,000 to sign upEUR 1,800 a year per LIR account + EUR 50 a year per ASNfrom January 1, 2027: EUR 1,894 a year, the first ASN includedSponsored End User: the LIR's own price, not verifiedfee page

ARIN1,366 new in 2025634 of them 16-bit · 1,280 so far in 2026Any organisation: its first ASN on request, with no multihoming test. A further one needs its own routing policy or another technical reason.16-bit numbers: no choice: every ASN counts as 4-bytePolicy: NRPM 2025.1 §5Directly, in ARIN Online, then sign the Registration Services Agreement. No membership or sponsor needed.USD 275 a year for up to 3 ASNsfrom January 1, 2027: USD 288.75 a year+ USD 50 for a new Org IDfee page

APNIC1,203 new in 20259 of them 16-bit · 951 so far in 2026A network that is multihomed, or needs to interconnect with another AS, now or soon after.16-bit numbers: no choice since 2010Policy: APNIC-127 §10As a member or a non-member account, or through the economy's national registry.AUD 500 to sign upAUD 500 a year (with an ASN only)two ASNs per account freeNon-member and national-registry fees: not verifiedfee page

LACNIC624 new in 202510 of them 16-bit · 629 so far in 2026A network that interconnects with other ASes now or within 6 months, and details its routing policy.16-bit numbers: on request, with a technical reasonPolicy: LACNIC Policy Manual v2.21 §3Directly, as an ISP or an end user; in Brazil and Mexico through Registro.br and IAR.MX.USD 1,000 onceUSD 500 for a Nano or Micro ISP's first ASNno yearly fee for an ASN alonefee page

AFRINIC175 new in 20257 of them 16-bit · 151 so far in 2026A resource member that interconnects with more than one AS, or shows a unique routing policy, now or within 6 months. Multihoming isn't required.16-bit numbers: no choice since 2011Policy: CPM v1.6 §7As a resource member; an ASN-only End User membership exists.USD 400 once + USD 50 a year (End User, ASN only)The fee page says it reflects 2008 unless amendedfee page

Policies and fees read on October 23, 2026; ARIN's and RIPE NCC's fees change on January 1, 2027.

New numbers: AS numbers whose current assignment is dated that year, nro-delegated-stats, Oct 23, 2026; a re-assigned number counts in its new year. Each registry's own page is the authority.

Is an ASN's country where its users are?

Not always. An ASN's country is where its holder registered it, which is often, but not always, where its addresses are used.

Jio is registered in India, and DB-IP places 99.9% of its IPv4 space there. Cloudflare is registered in the United States, but its anycast addresses answer from data centres around the world: DB-IP's guesses spread its space over 124 countries. To place one address, use an IP lookup; for a CDN there's no single place to find.

Registration: nro-delegated-stats · IPv4 space: RIPE RIS (seen by ≥ 10 peers, overlaps collapsed) joined with IP Geolocation by DB-IP (City Lite, October 2026, CC BY 4.0). Anycast space has no true country.

What is my ASN?

Your ASN is your internet provider's. A home or mobile connection has no AS number of its own: it reaches the internet through its provider's network, and that network's number is the one sites see.

Press My ASN above, or open What Is My ISP: it shows your provider, its AS number and how many people in your country use it. Your own network is shown only on your screen, never in a link or an image.

Whose number your connection uses

Your device192.0.2.442001:db8::44
Your routerno AS number
Your provider's networkAS64496Example Telecom
The internetsees AS64496

What Is My ISPyour provider, its AS number and its users in your country, on your screen only

Made-up example on documentation numbers: AS64496 (RFC 5398), 192.0.2.44 (RFC 5737) and 2001:db8::/32 (RFC 3849).

Sources

Every number on this page comes from one of these, and each one is named beside the number it gives. The credits stay in English, as their licences ask.

Routing data: RIPE NCC Routing Information Service (RIS), https://www.ripe.net/ris (riswhoisdump IPv4 2026-10-23 18:13 UTC, IPv6 2026-10-23 18:30 UTC).
IP-to-AS ranges: IPtoASN (iptoasn.com), PDDL 1.0.
Registration dates and countries: the RIRs' delegated statistics (AFRINIC, APNIC, ARIN, LACNIC, RIPE NCC), NRO combined file of 2026-10-23.
The CAIDA UCSD AS Relationships (serial-2) - 2026-10-01, https://catalog.caida.org/dataset/as_relationships_serial_2
The CAIDA UCSD AS to organizations mappings (AS2Org) - 2026-10-01, https://catalog.caida.org/dataset/as_organizations
The CAIDA UCSD AS Rank - 2026-10-01, https://catalog.caida.org/dataset/as_rank
Users per network: APNIC Labs (stats.labs.apnic.net/aspop), 2026-10-15. (C) APNIC Pty/Ltd. Re-use with attribution permitted.
IP Geolocation by DB-IP (CC BY 4.0), 2026-10.
Live IP-to-AS: Team Cymru IP-to-ASN mapping.
Registry records are fetched by your browser directly from the registry and shown as received; that registry's terms apply.

The RIPE Routing Information Service (RIS) is a RIPE NCC service. With the help of network operators all over the world, RIS employs a globally distributed set of Remote Route Collectors (RRCs), typically located at Internet Exchange Points, to collect and store Internet routing data. Volunteers peer with the RRCs using the BGP protocol and RIS stores the update and withdraw messages. RIS data can be accessed via:
RIPEstat, the “one-stop shop” for all available information about Internet number resources. RIPEstat uses individual widgets to display routing and other information
RIS Live, a real time BGP streaming API allowing server-side filtering of BGP messages by prefix or autonomous system
RIS Raw Data, available for each route collector, with state dumps and batches of updates made available periodically
RISwhois, that searches the latest RIS data for details of an IP address using a plaintext “whois”-style interface. It is useful when querying RIS data using scripts.

ASN lookup: frequently asked questions

What does ASN stand for?

ASN stands for autonomous system number: the number that identifies one network in internet routing. An autonomous system is a group of IP prefixes run by one or more operators under a single routing policy, such as Cloudflare (AS13335) or Deutsche Telekom (AS3320). The same letters mean an advance shipping notice in logistics and an associate of science in nursing, which is why search results mix them.

Is an ASN the same as an IP address?

No. An IP address identifies one device or service, while an ASN identifies a whole network that holds many addresses. AS15169, Google's main network, announces 1,247 IPv4 and 176 IPv6 prefixes that RIPE RIS sees widely, among them 8.8.8.0/24, the block that holds 8.8.8.8. Routers use the ASN to choose a path to the network and the address to reach the device.

How many AS numbers are there?

The RIRs' delegated statistics list 122,984 assigned AS numbers on October 23, 2026, out of 4,294,967,296 possible ones. 86,508 of them announce routes that at least 10 RIPE RIS peers see; the rest are registered but announce no route that many peers see. RIPE NCC has assigned the most (40,072), followed by ARIN (34,249), APNIC (31,432), LACNIC (14,415) and AFRINIC (2,816).

Can one company have more than one ASN?

Yes. Large networks often hold several, for separate regions, products or acquisitions. Deutsche Telekom's RIPE NCC record lists 12 AS numbers and Google's ARIN record 9, among them AS36040 for YouTube. This page lists the numbers in the same registry record under Overview, apart from upstreams and customers, and says which ones announce nothing.

What is a private ASN?

A private ASN is a number anyone can use inside their own network without registering it: 64512 to 65534 in the 16-bit range and 4200000000 to 4294967294 in the 32-bit range (RFC 6996). It's used for BGP inside a data centre or towards a provider that removes it, and must be removed before routes reach the internet; leaks still show up in RIPE RIS.

What is a Tier 1 network?

A Tier 1 network reaches every other network through peering and its own customers, without paying anyone for transit. There's no official definition or list: CAIDA uses a fixed clique of 18 transit-free networks, among them Lumen, Arelion, Cogent, NTT, Deutsche Telekom and AT&T. A network outside the clique can still be very large: Cloudflare and Google peer with hundreds of networks but aren't in it.

Why does RIPE NCC show 1970-01-01 as the registration date?

RIPE NCC's RDAP, the registry's own lookup service, shows 1970-01-01 for some older records and a 2002 database date for many others; neither is the assignment date. AS3320's record shows 1970-01-01, while RIPE NCC's delegated statistics say February 23, 1995. This page always takes the assignment date from the delegated statistics and treats an epoch date as unknown.

What is asdot notation?

Asdot (RFC 5396) writes a 32-bit AS number as two 16-bit halves joined by a dot: the high half, then the low half. AS65546 becomes 1.10 (1 × 65,536 + 10), and AS4200000000 becomes 64086.59904. Numbers below 65,536 look the same in both forms. You can type either form in the box above; the page shows the plain number.

What is AS0?

AS0 is reserved and never assigned. It may never appear in BGP: a route with AS0 in its path is malformed, and routers treat it as withdrawn (RFC 7607). It does have one use in routing security: a ROA that names AS0 says a block of addresses should not be routed by anyone (RFC 6483), which holders use for space they don't announce.

Why does my provider's ASN show another country?

An ASN's country is where its holder registered it, not where you are. Networks that serve several countries often register in one: Cloudflare is registered in the United States, while its addresses answer from data centres everywhere. For where an address is used, an IP geolocation database is the better guess, and it can still be wrong for mobile and anycast networks.

Do the networks know I looked them up?

The network isn't contacted. A plain AS number is answered from static tables on our site, and your browser asks the registry (ARIN, RIPE NCC, APNIC, LACNIC or AFRINIC) and CAIDA directly, so they see your IP address and the number you asked for, as with any visit to their sites. We keep no log of what you look up.

Where does this page get its data?

Routes come from RIPE NCC's Routing Information Service, IP-to-AS ranges from IPtoASN, assignment dates and countries from the five RIRs' delegated statistics, relationships, rank and organisations from CAIDA's datasets, user counts from APNIC Labs, and address locations from DB-IP. The registry record is fetched by your browser from the registry itself and shown as received.

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ASN Lookup

What is an ASN (autonomous system number)?