Why Google Owns AS15169 and Cloudflare Owns AS13335
Most people know what an IP address is.
Ask someone what 8.8.8.8 is, and there's a good chance they'll recognize it as Google's DNS server.
But ask them what AS15169 is?
Silence.
And that's exactly why attackers, bug bounty hunters, and security researchers pay attention to Autonomous System Numbers (ASNs).
Because while IP addresses tell you where a device lives, ASNs tell you who owns the neighborhood.
Once you understand that difference, the internet starts looking very different.
The Day I Stopped Looking at IP Addresses
When I first started learning reconnaissance, I was obsessed with domains and IPs.
I'd find a website.
Resolve its IP.
Run some scans.
Move on.
Simple.
Then I discovered ASN enumeration.
Suddenly, a single IP address wasn't just a server anymore.
It became a clue.
A breadcrumb leading to hundreds—sometimes thousands—of other assets owned by the same organization.
That's when I realized:
IP addresses show individual houses.
ASNs show entire cities.
And that's where recon gets interesting.
What Is an ASN?
An Autonomous System Number (ASN) is a unique identifier assigned to a network or group of networks controlled by a single organization.
Think of the internet as a giant global postal system.
Every house has an address.
That's your IP address.
But houses belong to neighborhoods.
Neighborhoods belong to cities.
Cities belong to states.
An ASN is like the official identifier for that city.
Instead of tracking one address, you're identifying the organization responsible for an entire section of the internet.
The Simple Analogy
Imagine you're standing outside a warehouse.
You see one truck parked outside.
That truck is an IP address.
Most people stop there.
But a hacker asks:
"Who owns the logistics company?"
The logistics company is the ASN.
Once you know who owns the company, you can discover:
- Other warehouses
- Delivery centers
- Distribution hubs
- Regional offices
The same principle applies online.
Why Does Google Own AS15169?
Google operates one of the largest networks on Earth.
Millions of servers.
Data centers on multiple continents.
Global infrastructure.
To manage all that traffic, Google owns:
AS15169
This ASN represents a massive portion of Google's network infrastructure.
If you look up AS15169, you'll find countless IP ranges associated with Google services.
Examples include:
- Search
- Gmail
- YouTube
- Google Cloud
- Maps
- Android services
When internet providers need to route traffic toward Google, they don't think in terms of individual servers.
They think in terms of AS15169.
It's the network's identity card.
Why Does Cloudflare Own AS13335?
Cloudflare's ASN is:
AS13335
If you've spent any time in cybersecurity, you've probably encountered Cloudflare without realizing it.
Millions of websites rely on Cloudflare for:
- DDoS protection
- CDN services
- WAF protection
- DNS services
Because Cloudflare sits in front of enormous amounts of internet traffic, it maintains its own massive autonomous system.
When you identify AS13335 during reconnaissance, you're often looking at infrastructure connected to Cloudflare's global network.
And that can reveal useful context about how a target's infrastructure is structured.
Why Hackers Care About ASN Enumeration
Here's where most guides stop.
They explain what an ASN is.
Then they move on.
But the real value comes from understanding what ASNs reveal.
Let's say you discover:
example.com
Most beginners start looking for subdomains.
That's fine.
But an experienced recon practitioner asks:
"Which ASN owns this infrastructure?"
Because one ASN can expose far more assets than a single domain ever will.
From One Domain to Hundreds of Assets
Imagine this chain:
example.com
↓
ASN Discovery
↓
Associated IP Ranges
↓
Additional Hosts
↓
Expanded Attack Surface
One domain becomes:
- Multiple subdomains
- Multiple IP ranges
- Multiple services
- Multiple opportunities for discovery
That's why ASN enumeration is often considered one of the most powerful reconnaissance techniques available.
A Real-World Example
Think about a shopping mall.
A website is one store.
An IP address is the store's street address.
Most people stop there.
An ASN tells you who owns the entire mall.
Now you can investigate every other store inside the property.
Different entrances.
Different businesses.
Different security levels.
The perspective changes completely.
How to Find ASN Information
One of the easiest tools for ASN research is:
he.net
Hurricane Electric's BGP Toolkit allows you to search:
- Domains
- IP addresses
- ASNs
- Routing information
For example:
google.com
can lead you to:
AS15169
From there, you can explore:
- Advertised prefixes
- Network ownership
- Associated ranges
- Routing paths
It's like moving from a street map to a satellite view.
The Hidden Recon Advantage
Here's what many beginners never realize.
A vulnerability scanner only examines what you already know exists.
Reconnaissance helps you discover what you didn't know existed.
And ASN enumeration is one of the fastest ways to expand that visibility.
A forgotten server.
A legacy IP range.
An acquired company's infrastructure.
A regional deployment.
All of those can become visible through ASN research.
Not because you're scanning harder.
Because you're thinking bigger.
Common ASN Numbers You Should Recognize
The more reconnaissance you do, the more familiar these become.
| Organization | ASN |
|---|---|
| AS15169 | |
| Cloudflare | AS13335 |
| Microsoft | AS8075 |
| Amazon | AS16509 |
| Meta (Facebook) | AS32934 |
Over time, seeing these numbers becomes second nature.
Just like recognizing a familiar domain.
Why This Matters More Than Ever
Modern organizations don't operate from one server.
They operate from cloud platforms, regional networks, CDNs, APIs, and distributed infrastructure.
That means understanding ownership is becoming more valuable than understanding individual hosts.
And ownership is exactly what ASNs reveal.
Think about it this way:
IP addresses tell you where something is.
ASNs tell you who it belongs to.
That's a much more powerful question.
Final Thoughts
Most people learn domains.
Some learn IP addresses.
Very few learn ASNs.
That's a mistake.
Because the moment you understand Autonomous System Numbers, the internet stops looking like a collection of websites and starts looking like a collection of interconnected networks.
And that's how hackers, bug bounty hunters, and security researchers see the web.
Not as pages.
Not as servers.
But as infrastructure.
The next time you discover an IP address, don't stop there.
Ask a better question:
Who owns the network behind it?
That's where the real reconnaissance begins.