What Are ISP Proxies? A Plain Explanation

In short: An ISP proxy is a static IP address that runs on server hardware in a data centre and is on a named internet provider’s network. It answers at server speed, and a network lookup returns that provider’s name. You hold the address for the whole period you pay for: it stays the same, and nobody else uses it in the meantime.

An ISP proxy combines two things you normally get from different kinds of proxy: a server in a data centre, and an address on an internet provider’s network. ProxyJam sells this product, and the explanation compares no vendors. Setup is covered on the ISP proxies page, and our editorial policy sets out how pages like this are sourced and corrected.

What makes a proxy an ISP proxy?

Two facts define an ISP proxy: where its machine sits and whose network its address is on. The second is a public record that anyone can check.

Where the machine is

The address answers from a rack, on a data-centre link. It does not depend on a household router staying plugged in, it does not share a domestic uplink with someone streaming television, and it responds at the speed you would expect from a server.

Whose network the address is on

Anything on the internet that wants to know what kind of connection a request came from looks up which network announced the address. For an ISP proxy that lookup returns an internet provider, and for an ordinary server it returns a hosting company. The record is public and free to check, and this product was built around it.

Why do ISP proxies have two names?

Each name describes a different property of the same product. ISP proxies says whose network the address belongs to. Static residential proxies says how the market files it: residential by network, static because the address holds still.

Some sellers use both names, on two different pages. The market keeps both because buyers arrive using both phrases, and a page written for one phrase does not always answer the other. Our catalogue follows the same practice: the ISP proxies page and the static residential proxies page sell the same addresses.

How a lookup tells the proxy types apart

A lookup of the network behind an address returns an operator’s name, and that name tells a site which type of proxy it is looking at. The network is identified by its ASN (autonomous system number). RFC 1930, the IETF’s guideline on autonomous systems, defines an autonomous system as “a connected group of one or more IP prefixes run by one or more network operators which has a SINGLE and CLEARLY DEFINED routing policy”. IANA allocates AS numbers to the five regional internet registries (AFRINIC, APNIC, ARIN, LACNIC and RIPE NCC), which assign them to network operators and publish who holds each one.

A site needs that one lookup and a list of hosting providers to recognise a datacenter address. A datacenter proxy is therefore transparent to any target that cares to look. The same query on an address announced by an internet provider returns that provider’s name as the network it comes from. On a leased block the registration itself can name a different holder, which the provider routes for.

You can watch the lookup happen. Our What Is My IP page prints the internet provider and the network (ASN) of whatever address reaches it. Open it on your own connection, then set a proxy in your browser (our free ProxyJam Connector extension does it in one click) and reload: the two lines change to the proxy’s, naming a hosting company for a datacenter address and a carrier for an ISP one.

Claims of undetectability deserve scepticism. An ISP address sits on a real internet provider’s network, and the routing record is public for anyone to query.

What are ISP proxies good at?

ISP proxies suit any job where the target has to recognise you as the same visitor from one week to the next.

• Logged-in work on accounts you own or are authorised to run. A session established from one address and continued from another can look, from the far side, like an account being taken over, and a fixed address keeps the session where the site expects it.
• Access granted to an address. Allow-lists, API keys bound to an IP and partners who admit a named address all need the address to still be yours next month.
• Measurement over time. Comparing this week with last week works only if the vantage point held still, and a pool moves it on every run.
• Long-running connections. A connection held for hours ends when the address underneath it changes, whatever a sticky window promised.

When is an ISP proxy the wrong tool?

An ISP proxy is a poor fit for broad crawling, for volume against targets that check nobody, and for anyone hoping to become impossible to block.

• Breadth. A job that touches many domains once each gains from arriving as a new visitor every time. A rotating pool supplies that and bills for the traffic, and a fixed address is the wrong shape of purchase for such a job.
• Volume against indifferent targets. When nothing checks who is asking, nobody looks at the internet provider’s registration either, and a datacenter address does the same work for less.
• Immunity from blocking. No address has it. A fixed address on an internet provider’s network removes one reason to be refused on sight, and a target can still refuse it for what you do once connected.

How are ISP proxies priced?

Providers charge for the address and the period. You hold one specific address for the time you pay for, so that is what the bill measures. A per-gigabyte product looks inexpensive on a small job and becomes unpredictable on a large one. A per-address product costs the same for a light month as for a heavy one, which makes the bill a number you choose before the work starts.

We price each offer per IP per month. A longer period or a larger order raises the total, and the monthly rate per IP stays the same; the offers are listed on the pricing page. Traffic is unmetered. Each ProxyJam proxy may hold up to 100 concurrent sessions, and once it has transferred 50 GB in a calendar month its ceiling drops to 10 for the rest of that billing period (Terms of Service, section 2.4).

The catalogue currently offers these addresses in 77 countries, each on a named carrier, and the country list is on the ISP proxies page.

How do you choose between ISP, residential and datacenter proxies?

Ask whether the target needs to recognise you, because the answer settles most of the choice.

If it does, you want an address that holds still. The registration question then decides whether a datacenter one will do. A consumer-facing target is likely to treat a hosting range with suspicion, which points to an ISP address. That holds for work the target allows; getting past a site’s own access rules is prohibited by section 5 of our Acceptable Use Policy.

A job where every request should come from a different stranger belongs on a rotating pool, and you are reading about the wrong product. We do not sell rotating or datacenter addresses yet; the rotating residential and datacenter pages explain how each one works.

For a target that has to recognise you, the ISP proxies catalogue lists every country and carrier. Three follow-ups go further: ISP against rotating residential compares holding one address with drawing from a pool, residential against datacenter walks through what a checker reads, and mobile against residential explains what a carrier address adds.