ASN Organizations: The Companies Behind the Internet's Routing System

Open a terminal and trace the route to any website. Between your device and the destination, you'll pass through autonomous systems with names like COMCAST-7922, ATT-INTERNET4, GOOGLE, and CLOUDFLARENET. These aren't random labels. They're the registered identities of the organizations that actually operate the Internet — the companies, universities, and government agencies that own the routers, lease the fiber, and decide how your packets travel.

Every autonomous system has a number. Behind every number is an organization. And that organization has a name, an address, a contact email, and a story. You can look up any of them, right now, for free.

This is the Internet's deed registry, and most people don't know it exists.

What an ASN Organization Actually Is

An Autonomous System Number is a unique identifier assigned to a network that controls its own routing policy¹. But an ASN doesn't exist in a vacuum. Someone had to apply for it. Someone had to justify why they needed it. Someone had to agree to maintain it.

That someone is the ASN organization — the legal entity registered as the custodian of that number. When you see AS13335, that's Cloudflare. When you see AS15169, that's Google. When you see AS7922, that's Comcast. The number is how routers identify the network. The organization is who's responsible for it.

Here's what makes this interesting: these organizations don't own their ASNs. They're custodians. The number is allocated to them by a regional authority, and if they stop using it, it goes back into the pool. The Internet's address system is more like a lease than a deed — nobody owns the numbers, everybody borrows them.

Reading the Names

ASN organization names follow loose conventions that, once you learn to read them, reveal the structure of the Internet like a map legend.

Company names are usually straightforward:

ISPs often include their ASN number in the name:

Large companies operate multiple ASNs for different divisions:

Why would Amazon need multiple autonomous systems? Because each ASN represents a distinct routing policy. Amazon's retail infrastructure, its AWS cloud platform, and its content delivery systems all make different decisions about how traffic should flow. Different routing policies require different ASNs².

Some names carry history:

AS1 — the very first assignable autonomous system number — belongs to Level 3 (now Lumen Technologies), a telecommunications company most people have never heard of whose fiber-optic cables run beneath cities across the country³. AS3 belongs to MIT. AS32 belongs to Stanford. These low numbers are fossils from the early Internet, when the organizations building the network got the first numbers because they were the network.

And AS721 belongs to the United States Department of Defense, managing roughly 29 million IPv4 addresses across thousands of prefixes⁴. The military doesn't just use the Internet — it operates a substantial piece of it.

The Registry System

ASNs don't materialize from nothing. They flow through a three-tier hierarchy:

IANA (Internet Assigned Numbers Authority) sits at the top. It allocates blocks of 1,024 ASNs at a time to the regional registries⁵.

Five Regional Internet Registries (RIRs) divide the world between them:

Organizations apply to their regional registry for an ASN. They need to demonstrate that they have a legitimate need — typically that they connect to multiple upstream providers (called multi-homing) and need to control their own routing decisions.

The cost varies. ARIN charges a flat $250/year for an ASN. RIPE NCC requires Local Internet Registry membership at €1,400/year, though sponsoring arrangements can reduce this. APNIC introduced a policy offering two free ASNs per member⁶.

This system means that if you know an organization's ASN, you can determine which registry issued it, and by extension, which region of the world that network calls home. An ASN in ARIN's range means North America. RIPE means Europe or Central Asia. The numbers carry geography.

How to Look Up Any ASN

The entire registry is public. Here's how to explore it:

Command Line

The simplest approach uses whois:

whois -h whois.arin.net AS7922

This returns Comcast's full registration record — organization name, address, registration date, abuse contacts, everything.

For a broader lookup that works across all registries:

whois AS15169

Web Tools

Several websites make ASN research visual and searchable:

• bgp.he.net — Hurricane Electric's BGP toolkit. Type any ASN and see its announced prefixes, peers, upstreams, and downstreams. This is the Swiss Army knife of ASN research.
• PeeringDB — A community-maintained database showing where networks physically interconnect. Look up AS15169 and you'll see every Internet exchange point where Google peers with other networks⁷.
• IPinfo.io — Clean, modern ASN lookups with visualizations of prefix announcements and geographic distribution.
• CAIDA AS Rank — Ranks autonomous systems by their "customer cone" — the number of networks that route through them.

From an IP Address

You can also work backward. If you have an IP address and want to know which organization is responsible for it:

whois 8.8.8.8

This reveals that 8.8.8.8 belongs to Google (AS15169). Every IP address on the Internet maps to an ASN, and every ASN maps to an organization.

What the Numbers Reveal

Start exploring ASN data and patterns emerge that reveal the Internet's actual structure — not the abstract cloud diagram, but the physical and corporate reality.

The Internet Is Surprisingly Concentrated

AT&T's AS7018 announces over 89 million IPv4 addresses across more than 8,000 prefixes⁸. Comcast's AS7922 covers nearly 68 million IPv4 addresses⁹. Amazon's AS16509 controls over 48 million¹⁰. A handful of organizations control vast portions of the Internet's address space.

CAIDA's AS Rank tracks this concentration. The top 10 autonomous systems, measured by customer cone, serve as transit for enormous percentages of global Internet traffic. The Internet may be decentralized in theory, but in practice, it passes through a remarkably small number of organizations.

Corporate Mergers Leave Routing Fossils

When one company acquires another, the acquired company's ASN often survives. Level 3 absorbed multiple telecommunications companies over the years, and their old ASNs still appear in routing tables. CenturyLink acquired Level 3, then rebranded to Lumen Technologies — but AS1, registered as LVLT-1, still carries the Level 3 name¹¹.

ASNs can be transferred during mergers and acquisitions, but the process requires legal documentation and registry approval¹². The result is that the Internet's routing tables contain corporate archaeology — you can trace the history of telecom consolidation by reading ASN records.

Universities Were Here First

The lowest ASN numbers read like a roll call of the institutions that built the Internet. MIT holds AS3. Stanford holds AS32. These numbers were assigned in the 1980s and 1990s when the Internet was still an academic project. The fact that universities hold some of the earliest ASNs isn't trivia — it's a reminder that the Internet was built by researchers, not corporations.

The Military Is Wired In

The Department of Defense doesn't just send traffic over the Internet — it operates autonomous systems within it. AS721 manages roughly 29 million IPv4 addresses. The DoD Network Information Center (DNIC) maintains multiple ASN blocks, reflecting the military's deep integration with the global routing system.

The 16-Bit Wall

Originally, ASNs were 16-bit numbers, limiting the total to 65,536 possible assignments. By the mid-2000s, this ceiling was approaching fast. In 2007, the IETF extended the ASN field to 32 bits, expanding the pool from 65,536 to over 4.2 billion possible numbers¹³.

The original 16-bit range (1–65535) is now referred to as "2-byte ASNs," and the extended range (65536–4294967295) as "4-byte ASNs." Most new assignments come from the 4-byte range. The transition took years — BGP routers needed software updates to understand the larger numbers, and some older networks were slow to upgrade.

As of 2025, roughly 120,000 ASNs have been allocated worldwide¹⁴. That's less than 0.2% of the 16-bit space and a vanishingly small fraction of the 32-bit space. We won't run out of ASNs again.

Why This Matters

Understanding ASN organizations changes how you see the Internet.

When your connection slows down, a traceroute might show your packets passing through AS7018 (AT&T) before reaching AS13335 (Cloudflare). Now you know exactly which organizations are involved and can identify where the problem lies. When a news headline says "major cloud outage," you can check which ASN was affected and understand the blast radius.

More fundamentally, ASN data makes the Internet's power structure visible. The Internet isn't an abstract cloud. It's a specific set of organizations, operating specific networks, making specific routing decisions. Those organizations have names. They have addresses. They have phone numbers. And every one of them is listed in a public registry that anyone can search.

The Internet is not mysterious. It just requires you to know where to look.