How to Prove a US Proxy Is a Real SIM, Not a Datacenter

Sellers of US proxies use the word mobile freely, and a buyer sitting in Shenzhen or Ho Chi Minh City has no way to open the rack and look. What you can do is make the network tell you. Every public address carries facts that cannot be faked by a seller: who announces it, which organisation registered it, how it is classified by the databases websites rely on, and how it behaves when the connection is reset. This guide gives five checks, in order, that separate a real carrier SIM from a datacenter server or a VPN exit with a mobile label. Real US Proxies publishes it because every line we rent passes all five, and because a buyer who knows how to check is the buyer we want.

Check one: the ISP and organisation fields

Open any public IP lookup, paste the proxy's exit address, and read the ISP or organisation field. A real SIM returns the carrier's own name: T-Mobile USA, Verizon Wireless or Cellco Partnership, AT&T Mobility. A datacenter address returns a hosting company, a cloud provider or a small network nobody has heard of. A VPN exit returns the VPN vendor or its hosting provider. The field is filled from the registry record of the address block, which the seller cannot edit. If the carrier's name is not there, stop; nothing else matters.

Check two: the autonomous system number

Beside the organisation most lookups print an AS number, the identifier of the network that announces the address to the rest of the internet. The three national US carriers use a small set: AS21928 for T-Mobile, AS22394 and AS6167 for Verizon Wireless, AS20057 for AT&T Mobility. A hosting company has its own numbers and so does every VPN provider. Because routing announcements are public and recorded by many independent observers, an AS number is the hardest fact on the page to counterfeit. Compare the number in the lookup with that list.

Check three: the connection type

Reputation databases classify every address block: hosting, business, residential, cellular. The field may be labelled connection type, usage type or network type. A real SIM reads cellular, mobile or wireless. A datacenter reads hosting or data center. Some VPN exits sit on residential-looking blocks and read residential, which is still not cellular. This classification is what websites consult when deciding how much to trust a visitor, so it is the field that decides whether the proxy will behave like a phone in practice, not only in a seller's description.

Check four: what happens on rotation

Ask the seller to rotate the address, or use the rotation link if you have one, and look the new address up. A real SIM returns a new address from the same carrier, the same AS number and the same region: the device re-attached to the carrier's network and the gateway handed it another mapping from its pool. A datacenter proxy rotating between servers may jump between hosting companies, countries or AS numbers, because the seller is switching exits rather than re-attaching a SIM. Repeat two or three times; the carrier and region should never change.

Check five: carrier-grade NAT and the crowd

A real carrier address is shared with hundreds or thousands of ordinary subscribers through carrier-grade NAT, and that leaves a visible trace: fraud checkers show a non-zero score or a history, because other people have used that public address before. A fresh datacenter address often shows a clean zero, which is not a good sign here; nobody lives behind it. Counter-intuitively, a little history is evidence of a real phone network. The Real US Proxies guide on fraud scores explains the fields in detail.

Running all five in ten minutes

Rent two hours, which costs $2 on 4G or $3 on 5G and never renews, and run the checks in order with a screenshot of each. Keep the screenshots: they are the proof you will want later if an account is ever questioned, and they are the same screenshots our own support team sends when a customer asks whether a line is real.

1. Paste the exit address into a public IP lookup and read the ISP or organisation field; it must name a US carrier.
2. Read the AS number and compare it with the carrier's known numbers above.
3. Read the connection type; it must say cellular, mobile or wireless.
4. Rotate the line and look the new address up; carrier, AS number and region must be unchanged.
5. Check a fraud scorer; a modest non-zero history is normal for a shared carrier address.

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