ASN Targeting vs Geo Targeting

What an ASN is

The internet is a network of networks. Each one that runs its own routing policy is an Autonomous System, identified by an Autonomous System Number. The guidelines for when a network should have its own ASN were set out in RFC 1930, and the regional internet registries assign the numbers.

Every public IP prefix is announced by an ASN, and that announcement is public. Anyone can look up which ASN originates an address and who holds that ASN. RIPEstat, run by the RIPE NCC, exposes this through an open API. Its AS overview call returns whether an ASN is announced and the name of its registered holder (RIPEstat AS overview), and its network info call maps an IP address to the prefix and ASN that announce it (RIPEstat network info).

Data providers add a classification on top. IPinfo, for instance, labels each ASN as isp, business, hosting or education (IPinfo ASN data). This is why a datacenter proxy is so easy to spot: the ASN belongs to a hosting company. A mobile proxy's ASN belongs to a carrier.

The ASN is also the one network fact a proxy cannot disguise. Headers, browser settings and even the operating system fingerprint can be changed, but the address your request arrives from is announced by whoever routes it, and that record lives in global routing tables, not in your client. So the first question in any proxy purchase is not where the exit is on a map but whose network it is on. Location is an estimate layered on top of that answer; the ASN is the answer itself.

A tested ASN lookup

Here is a short Python script that asks RIPEstat for the holder of four carrier ASNs. It uses only the standard library and retries if RIPEstat is slow.

import json, time, urllib.request

BASE = "https://stat.ripe.net/data"

def ripestat(call, resource, tries=3):
    url = f"{BASE}/{call}/data.json?resource={resource}&sourceapp=asn-guide"
    for attempt in range(tries):
        try:
            with urllib.request.urlopen(url, timeout=30) as r:
                return json.load(r)["data"]
        except OSError:
            time.sleep(2 * (attempt + 1))
    raise RuntimeError(f"RIPEstat did not answer for {resource}")

for asn in ["AS21928", "AS6167", "AS3209", "AS6805"]:
    d = ripestat("as-overview", asn)
    print(f"{asn:8} announced={str(d['announced']):5} holder={d['holder']}")

Output on 30 October 2026:

AS21928  announced=True  holder=T-MOBILE-AS21928 - T-Mobile USA, Inc.
AS6167   announced=True  holder=CELLCO-PART - Verizon Business
AS3209   announced=True  holder=VODANET Vodafone GmbH
AS6805   announced=True  holder=TDDE-ASN1 Telefonica Germany GmbH & Co.OHG

Swap as-overview for network-info and pass an IP address to find which ASN announces your own exit. A carrier can announce its ranges from more than one ASN, so treat these as examples, not a complete list for each carrier.

How GeoIP places mobile IPs

A GeoIP database is an estimate built from registry data, routing, operator feeds and measurements. It is not a lookup of where a device physically is.

Fixed broadband ranges are relatively easy to place, because a block of addresses usually serves one area. Mobile ranges are harder. Carriers route subscriber traffic through a limited number of gateways and carrier-grade NAT systems, and one public address can serve devices across a wide region. The database may report the city of the gateway, the registered address of the block, or only the country.

Operators can help by publishing a geofeed, a simple file that states where each of their prefixes is used, in the format defined in RFC 8805. Not every carrier publishes one, and databases decide how much weight to give it.

Even large consumers of this data treat it as approximate. Google's help pages say an IP address gives only a general area, similar to a phone area code, and that Google sometimes cannot estimate a location from it at all (Google: how location works in Search).

The practical rule: for a mobile line, trust the country, read the region as approximate, and do not promise a city to a client unless you have tested it on the database that client's target uses. Our guide to a proxy showing the wrong location walks through those checks.

When the carrier matters more than the city

Geo targeting answers "where does this request appear to come from". ASN targeting answers "which network is it on". Several jobs care much more about the second question.

Carrier-specific content. Some apps, offers and billing flows behave differently by carrier: carrier billing, zero-rated services, network-locked promotions or carrier-branded app stores. Testing them needs a SIM on that carrier, wherever it sits in the country.

Consistency for accounts. A platform that sees an account log in from the same carrier day after day sees an ordinary pattern, even when the city in a GeoIP database wobbles. An account that hops between carriers, or between a carrier and a hosting network, looks less ordinary.

Network-level rules. Sites sometimes rate-limit or challenge whole ranges. MaxMind's dataset puts Cellular in its own class, apart from Cable/DSL and Corporate (MaxMind connection type documentation), so a site that uses it can write one rule for all cellular traffic from a carrier rather than for a city.

Ad verification. An ad served to mobile users on one carrier may differ from one served on another, so the carrier is part of the test case.

City targeting still matters for local search results, maps and store availability, where the target uses location directly. For those, check how precise the target really is before paying extra for a city. Many targets that look location-aware only use the country or a broad region, and a request on the right carrier in the right country gives the same answer as one pinned to a city.

Choosing lines by carrier from the live catalog

Coronium lists stock by country and carrier, so you choose the network first. The table updates from the live catalog each time this page loads.

Carrier pages go deeper on the networks with dedicated pages: T-Mobile mobile proxies, Verizon mobile proxies, Three UK mobile proxies and Vodafone mobile proxies. For the full country list, see mobile proxy locations.

Two details matter when you pick. A replacement device, if you need one, has new credentials and may be on a different carrier, so note the carrier when you assign a line to an account. And regions within a country vary by carrier; the country pages show which regions each carrier has in stock.

Planning a project by carrier

Once you accept that the carrier is the main variable, project planning gets simpler. Work through four questions before you buy.

Which carriers does your audience use? For an app test or an ad check, pick the carriers your real users are on. Regulators and carriers publish market share figures in most countries; the largest two or three networks usually cover the bulk of mobile users.

Does the target treat carriers differently? Run the same small task on two carriers in the same country and compare the results: challenge pages, prices shown, content served. If there is no difference, you can choose by stock and price. If there is, the carrier becomes part of your test design.

How many identities do you need? One line gives one exit at a time. If you need several accounts on the same carrier, plan one line per account group and keep each group on its own line.

What happens on replacement? If a device fails and is replaced, the new one may be on a different carrier. Record the carrier against each account so you notice the change and can decide whether to move the account or wait for a line on the original network.

Write the answers down next to the line IDs. When results change months later, the record tells you whether the network changed too.

Checking an exit yourself

Do not take any provider's word for the network behind an address, including ours. Three checks take a minute.

1. Find your exit IP through the proxy with What is my IP in the same browser or client.
2. Look up the address in our ASN lookup tool, or call RIPEstat's network info endpoint, and confirm the holder is the carrier you bought.
3. Compare the country in two or three GeoIP sources. If they disagree on the city, that is normal for mobile ranges; if they disagree on the country, investigate before using the line for location-sensitive work.

Repeat the check after each rotation for the first few days. A new address should stay on the same carrier and in the same country. If it does not, contact support with the before and after addresses. To browse carriers and countries together, start from the mobile proxies overview.

How we checked

ASN holders were retrieved from RIPEstat with the script shown, on 30 October 2026. Standards and database behavior come from the RFCs and vendor documentation linked above. Coronium carriers, prices and stock come from the live catalog when the page renders. We did not measure GeoIP accuracy for any carrier.

Frequently asked questions