ASN (Autonomous System Number)

Two addresses in the same city can belong to a home provider and to a rented server room, and the network number is what tells them apart. A site reads it before it reads anything about your browser.

An ASN is the number of the network an address belongs to, and it says who runs that address rather than where it sits.

What the number stands for

The internet is a set of networks that agree to carry each other's traffic. Each of those networks is registered once and carries a number of its own.

Every address lives inside a block that belongs to one of them. The number never changes when you reload a page or clear anything, because it describes the address rather than you.

Why a site looks at it

The number is the cheapest way to sort visitors into groups without knowing anything about them.

It names the operator
A home provider, a mobile carrier and a hosting company are three different registrations, and the number says which one you came from.
It groups whole blocks at once
A rule written against one network covers every address inside it, so one bad neighbour affects addresses you have never used.
It outlives a rotation
A mobile address changes on every rotation and usually stays inside the same registration, so the group you belong to does not move with it.

Home line or server room

Residential and mobile addresses are registered to operators who sell connections to people. Datacenter addresses are registered to companies who rent out machines.

That difference is visible in the registry, which is why the two are priced differently and treated differently. Neither is forbidden anywhere, and the site you visit decides what it makes of yours.

What the app shows

The network panel in the app reads your own connection and shows the provider and the network number when the source it asked supplies them. A row with no value is left out rather than filled with a guess.

The exit check of a proxy is a different answer. It reports the address, the country, the city and the time to first response, and it carries no network number.

Often confused with

The IP address
The address is one point. The number is the whole block that address was issued from, and thousands of addresses share it.
The country
A network can carry addresses in several countries at once, and a country can hold hundreds of networks. Location and registration are separate answers.
The provider name
The name is text and is written differently by every source. The number is registered once and reads the same everywhere.

What this does not do

The app does not show the network number of a profile exit. The proxy check answers with the address, the country, the city and the timing, and stops there.
It does not sort or rank addresses by network. Rows sit in the library in the order they were pasted, and nothing scores them.
It does not tell you that an address belongs to a server room. That reading is made by the site you visit, and the app makes none of it.
It does not change which network you leave through. That is decided by the address you bought, not by anything a browser can set.

Check it

What is read, what is kept and what is left blank, each in a file you can open.

Where the exit answer is read, the network number included: apps/desktop/src/lib/exitGeo.js
The readers run against recorded answers from every source: apps/desktop/test/exit-geo.js
The rows of the network panel, with empty ones left out: apps/desktop/src/manager/renderer.js
What the proxy check answers with, and what it leaves out: apps/desktop/src/main/main.js · apps/desktop/test/proxy-check-uses-bridge.js

Questions

Can I change my ASN?: Not from a browser. The number belongs to whoever registered the address block, so changing it means leaving through a different address.
Does the app show the network number of my proxy?: No. The check through a proxy answers with the address, the country, the city and the time to first response, and nothing about the registration.
Is a datacenter network always a problem?: No. Plenty of sites never look, and the ones that do weigh it against everything else they see. It is one signal, not a verdict.
Does a changed fingerprint hide the network?: No. A fingerprint is read inside the page, and the network is read from the connection that delivered the page. Different layers, separate answers.
Where do I see the number for my own connection?: The network panel at the top of the app. The row appears when the source it asked returns it, and is left out when it does not.

Next to this

Give every profile its own exit

Put an address behind a profile and see the country it answers from before you open a window.

Download ARMANOS Proxies