# What Is My ISP? Check the ISP and ASN of an IP | ProxyJam What is my ISP? Find the provider and ASN an IP address is on with a free page, an RDAP query or an ASN lookup, and see why two lookups can disagree. - Canonical: https://proxyjam.com/blog/what-is-my-isp/ - Updated: 2026-10-28 - Language: en Your ISP is the network your connection reaches the internet through, and its autonomous system number (ASN) identifies that network in routing. [What Is My IP](/what-is-my-ip/) shows both for your own connection. For any address, a registry query names the holder of the block and an IP-to-ASN lookup names the network announcing it. To check a proxy, compare that network with the carrier you ordered. ## Compare an address with the carrier you ordered 1. **Note the carrier** Open the proxy in your dashboard and write down its address and the provider in its ISP field, the carrier you picked at checkout. 2. **Connect through the proxy** Set the proxy in a browser and open [What Is My IP](/what-is-my-ip/). Write down the Internet provider and Network (ASN) rows. 3. **Look up the routing** Run an IP-to-ASN lookup for the same address, such as Team Cymru's whois service, and note the origin AS and the BGP prefix. 4. **Compare by number** Check that both lookups return the same ASN and that it is the carrier's. A different organisation in the registry record is the holder of the block, which can differ from the network that announces it. 5. **Write down any difference** If the announcing network is not the carrier on your order, send support the address, the order number, both lookup outputs and the UTC time you ran them. ## Why two lookups name different organisations | | What you see | Which answer describes the routing | |---|---|---| | Holder and announcing network differ | The registry record names one organisation as the holder of the block, and an IP-to-ASN lookup names another network as the origin | The origin AS. A holder can let another network announce its block, and a signed route origin authorisation records that permission | | Block passed on to a customer | The registry returns a smaller record inside the provider's block, naming a business or a reseller | The origin AS, which is often still the provider's. A reassignment changes who uses the block, and the route can stay where it was | | Customer inside its provider's AS | A company holds a block of its own, yet the lookup shows its provider's ASN | The provider's AS. RFC 1930 advises a site connected to a single provider to place its prefixes in an AS of that provider | | One copy is behind | Two services return different networks for the same address on the same day | The one built from the most recent routing data. Each database is a copy, refreshed on its own schedule | | One network, two names | The same ASN appears under a brand in one tool and a legal name in another | Either. Once the numbers match, the two answers agree | | The wrong connection was checked | The lookup shows your home provider while you meant to check a proxy | Neither yet. Reload What Is My IP with the proxy on, or look the proxy's address up directly | Each row follows a document listed under Sources: RFC 1930 on autonomous systems, RFC 6483 on route origin authorisations, ARIN's rules on reassignments and the refresh schedule Team Cymru publishes for its mapping. We tested no lookup service for accuracy. ## Quick answers ### What is the difference between an ISP and an ASN? The ISP is the company that provides the connection. The ASN is the number its network goes by in routing, assigned through a regional internet registry. A lookup shows the ASN that announces the range your address is in, with the name of the organisation registered for that number. ### Does a lookup show my ISP when I use a VPN or a proxy? It shows the provider of the address a site receives, which with a VPN or a proxy on is the server's. What Is My IP works the same way, so open it on the connection you want to check. ### Why does my ISP appear under a name I do not recognise? A database prints the organisation registered for the AS number. That can be a parent company, a legal entity or the larger network a small provider connects through, since RFC 1930 advises a site with a single provider to use that provider's AS. Compare the ASN first, then query the registry for that number. ### Is a whois lookup the same as an RDAP lookup? They read the same registry data. Whois is the older text protocol on TCP port 43, and RDAP returns the records as structured JSON over HTTPS. ARIN describes RDAP as a Whois alternative. ### Does an ASN lookup show where an address is? Some lookups add the country code of the registry record. A location comes from a geolocation database, which estimates one place for a whole range, and What Is My IP shows Cloudflare's estimate beside the network. ### What if the network on my ProxyJam address is not the carrier I ordered? Write to support@proxyjam.com with the address, the order number and both lookups. Free replacements under section 2.5 of our Terms of Service cover an address that stops responding, moves outside the country you bought or is refused by the target you named at purchase. ## Sources - [IANA: Number Resources](https://www.iana.org/numbers), IANA allocating address pools to the five regional internet registries, and the region each one serves - [IANA: Autonomous System (AS) Numbers](https://www.iana.org/assignments/as-numbers/as-numbers.xhtml), AS numbers allocated to the registries, which assign them to network operators - [RFC 7020: The Internet Numbers Registry System](https://www.rfc-editor.org/rfc/rfc7020), the hierarchy from IANA through the regional registries to local registries and their customers - [RFC 1930: Guidelines for creation, selection, and registration of an Autonomous System](https://www.rfc-editor.org/rfc/rfc1930), the definition of an AS and the advice that a site with a single provider place its prefixes in that provider's AS - [RFC 4271: A Border Gateway Protocol 4 (BGP-4)](https://www.rfc-editor.org/rfc/rfc4271), the originating AS writing its own number into a route's AS path - [RFC 6483: Validation of Route Origination Using the RPKI and ROAs](https://www.rfc-editor.org/rfc/rfc6483), the signed record of an address holder authorising an AS to originate routes for its block - [RFC 9082: RDAP Query Format](https://www.rfc-editor.org/rfc/rfc9082), the ip and autnum query paths - [RFC 3912: WHOIS Protocol Specification](https://www.rfc-editor.org/rfc/rfc3912), whois as a text protocol on TCP port 43 - [ARIN: Whois/RDAP](https://www.arin.net/resources/registry/whois/rdap/), RDAP as a Whois alternative and the form of an IP network query - [ARIN: Reporting Reassignments](https://www.arin.net/resources/registry/reassignments/), reallocations and reassignments of a block to a provider's customers - [Team Cymru: IP to ASN Mapping](https://www.team-cymru.com/ip-asn-mapping), an address mapped to its BGP prefix, origin ASN and registry record, from feeds of more than 50 BGP peers refreshed every four hours - [RIPE NCC: RIPEstat](https://stat.ripe.net/), the routing and registry view of an address or prefix in a browser - [MaxMind: GeoLite ASN Databases](https://dev.maxmind.com/geoip/docs/databases/asn/), the autonomous system number and organisation fields a downloadable ASN database carries - [Cloudflare Workers: Request](https://developers.cloudflare.com/workers/runtime-apis/request/), the asn and asOrganization values What Is My IP displays - [RFC 5737](https://www.rfc-editor.org/rfc/rfc5737) and [RFC 5398](https://www.rfc-editor.org/rfc/rfc5398), the address 203.0.113.7 and the AS number 64496 used in the examples, both reserved for documentation An ISP lookup answers one question about an IP address: which network is it on? Our free [What Is My IP](/what-is-my-ip/) page answers it for your own connection. What follows explains what the provider name and the ASN in a lookup mean and gives three ways to check any address. It then covers why two lookups sometimes name different organisations, and how to compare an address you bought with the carrier named on the order. ProxyJam sells static residential (ISP) proxies, each on a named carrier's network, so the last part is a check our own buyers run. Our [editorial policy](/editorial-policy/) explains how articles like this are sourced and corrected. ## What do ISP and ASN mean in a lookup? Your ISP is the company whose network connects you to the internet. The rest of the internet knows that network as an autonomous system (AS), and its autonomous system number (ASN) is how routing refers to it. [RFC 1930](https://www.rfc-editor.org/rfc/rfc1930) defines an AS 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". Addresses and AS numbers come down the same chain, which [RFC 7020](https://www.rfc-editor.org/rfc/rfc7020) describes. IANA allocates pools of both to five regional internet registries, and each registry serves the networks in its region, directly or through local registries. The five are AFRINIC, APNIC, ARIN, LACNIC and RIPE NCC ([IANA](https://www.iana.org/numbers)). A provider receives blocks of addresses and an ASN from its registry, then hands addresses out to its customers. Networks tell each other which address ranges they can reach over BGP, the routing protocol between autonomous systems. The network that starts an announcement writes its own ASN into the route's path, which [RFC 4271](https://www.rfc-editor.org/rfc/rfc4271) calls originating the route. So when a lookup shows a provider for an address, it reports one of two records: the registry entry for the block, which names the holder, or the routing data, which names the AS announcing the block. A name appears beside an ASN because every AS number has a registration record naming the organisation that runs it. ## How do you check which ISP an IP address is on? Pick the method by whose address it is and which record you need. ### Your own connection: What Is My IP Open [What Is My IP](/what-is-my-ip/) in the browser you want to check. Its Internet provider and Network (ASN) rows show the network of the address the page received, as labelled by Cloudflare, which serves the page: the request's AS number and the organisation Cloudflare lists for it ([Cloudflare's Request reference](https://developers.cloudflare.com/workers/runtime-apis/request/)). Nothing on the card is saved. With a proxy or a VPN on, the rows show the server's network, because that is the connection the page receives. ### Any address: a registry query The registry record says who holds the block an address is in. RDAP is the current protocol for reading it, a JSON service over HTTPS that ARIN describes as "a Whois alternative" ([ARIN](https://www.arin.net/resources/registry/whois/rdap/)). Queries follow the paths [RFC 9082](https://www.rfc-editor.org/rfc/rfc9082) defines, `ip/` for an IPv4 or IPv6 address and `autnum/` for an AS number: ``` https://rdap.arin.net/registry/ip/203.0.113.7 https://rdap.arin.net/registry/autnum/64496 ``` Both values are reserved for documentation, so put the address you are checking in their place. When we tried it on 26 October 2026, ARIN's server answered a query for an address in RIPE NCC's region by redirecting it to RIPE NCC's RDAP server, so in our test one starting point covered both regions. The older whois protocol on TCP port 43 ([RFC 3912](https://www.rfc-editor.org/rfc/rfc3912)) returns the same kind of record as text: ``` whois 203.0.113.7 ``` If your system has no whois command, open the RDAP address in a browser or use RIPEstat, described in the next section. Read three things in the answer: the range of the block, the organisation, and the type of record. In ARIN's records a direct allocation came from the registry itself, and a reassignment or reallocation was passed on by a provider to a customer of its own. ### Any address: an ASN lookup by IP An IP-to-ASN lookup reads routing data and returns the AS that announces the address. Team Cymru's free [IP to ASN Mapping](https://www.team-cymru.com/ip-asn-mapping) service maps an address to "its BGP prefix, origin ASN, and registry record", from BGP feeds of more than 50 peers, refreshed every four hours: ``` whois -h whois.cymru.com " -v 203.0.113.7" ``` It returns one line with the AS number, the address, the BGP prefix, a country code, the registry, the allocation date and the AS name, in this shape (the values are documentation placeholders): ``` AS | IP | BGP Prefix | CC | Registry | Allocated | AS Name 64496 | 203.0.113.7 | 203.0.113.0/24 | US | arin | 2020-01-01 | EXAMPLE-NET, US ``` RIPE NCC's [RIPEstat](https://stat.ripe.net/) shows the same routing view in a browser. For an ASN lookup on its own, the registry's `autnum/` query returns the organisation behind the number. A downloadable database such as [MaxMind's GeoLite ASN](https://dev.maxmind.com/geoip/docs/databases/asn/) carries two fields per range, the autonomous system number and "the organization associated with the registered autonomous system number", and answers without sending the address anywhere. ### How others rate the address None of these lookups says whether an address is listed anywhere. Our [IP Checker](/ip-checker/) looks an address up in four published lists and asks three fraud-scoring services about it, then gives one verdict with each source's reading beside it. The check opens in the ProxyJam app and runs there once you sign in or create an account. Looking the address up in the published lists alone is free; the full check uses a free check if you have one and is otherwise charged to your wallet balance. ## Why do two lookups name different networks? They read different records, copied at different times. The table Why two lookups name different organisations lists the common cases, and three of them explain most disagreements. **The holder and the announcing network are different organisations.** A registry record names whoever holds the block, and a route names whoever announces it. They match when a provider announces its own addresses, and they part when a holder lets another network carry its block. The Resource Public Key Infrastructure gives that permission a signed form: a route origin authorisation (ROA) "provides a means of verifying that an IP address block holder has authorized a particular AS to originate routes" for the block ([RFC 6483](https://www.rfc-editor.org/rfc/rfc6483)). **A provider passed the block on.** ARIN calls it a reallocation when the provider's customer will issue pieces of the block to customers of its own, and a reassignment when the block is for the customer's own use ([ARIN](https://www.arin.net/resources/registry/reassignments/)). The registry record for the address can then name the customer, while the route still leaves through the provider's AS. RFC 1930 covers a related case. It advises a site connected to a single provider to place its prefixes in an AS of that provider, and not to create an AS of its own. A lookup can then show the provider's ASN even where the registry names the site as the holder. **A copy is out of date.** Every database is a copy made at some moment. Team Cymru refreshes its routing data every four hours, and a downloaded file is as current as the day it was built. When two answers disagree, run both again and compare them by ASN, since one network can appear under a brand in one tool and a legal name in another. For a proxy address, the answer that describes how its traffic reaches the internet is the announcing network, and it is the network we mean when we name a carrier on an address. A site that reads another database may still show a different name for it. ## How do you check an address you bought? By the network that announces it. Every ProxyJam ISP address is sold with a named carrier, and that name is the network that announces the address. The holder in the registry record can be another organisation, which is ordinary on a reassigned or leased block. The steps in Compare an address with the carrier you ordered take you from the order to both lookups; keep their outputs, since support needs them to look into a difference. A match between the announcing network and the carrier you ordered is the result to expect, whatever name the registry record carries. If it is another network, write to [support@proxyjam.com](mailto:support@proxyjam.com) or the Telegram support bot listed on our [FAQ](/faq/), with the address, the order number, both outputs and the UTC time you ran them. Our terms set out these related rights: - **Free replacement.** Section 2.5 of the [Terms of Service](/terms-of-service/) names three grounds: the address stops responding, its geolocation moves outside the country you bought, or the target you identified at purchase refuses it. Free replacements are limited to 20 % of the addresses in an order per calendar month. - **The first order.** Under section 2 of the [Refund Policy](/refund-policy/), you can request a refund within 24 hours of your first order, for up to ten addresses, once per customer, and using the proxies in that window does not void the request. A network lookup shows where an address is announced today. It cannot show how the address was used before you held it. For how others rate it now, run the [IP Checker](/ip-checker/). ## When does a lookup not answer the question? - **Where a device is.** A lookup names a network. A location is a geolocation database's estimate for the whole range, a separate dataset; what sites read to place a visitor is covered in [viewing your website from another country](/blog/view-website-from-another-country/). - **Who used an address.** Which subscriber held an address at a given time is known to the provider, which does not publish it. - **Whether a site will accept an address.** Each site applies its own rules. The IP Checker reports what published lists and scoring services say, and only a request to the site itself settles the rest. - **An address on a mobile network.** We do not sell mobile addresses yet. The [mobile proxies page](/mobile-proxies/) explains how they work. In the United States, the [US ISP proxies page](/isp-proxies/usa/) lists the 19 named carriers our addresses are on, so you can look a carrier's network up before you order. The same product is described under its other name on [static residential proxies](/static-residential-proxies/). The [definition of an ISP proxy](/blog/what-are-isp-proxies/) explains why a network lookup returns a provider for an address served from a data centre, and [residential vs datacenter proxies](/blog/residential-vs-datacenter-proxies/) compares what the registry shows for each type. The catalogue covers 77 countries on the [ISP proxies page](/isp-proxies/), priced per IP per period on the [pricing page](/pricing/).