Use our ASN Lookup tool to find publicly available registration information for an Autonomous System Number (ASN). Enter a number such as AS17557 or 17557 to check its registered network name, organization, Regional Internet Registry, country code, registration status, and other available details.
You can also open the original registry record to verify the information.
Find ASN registration details
Enter a public Autonomous System Number to see details from the Regional Internet Registry. Example: AS17557.
ASN registration details are not live connection tests. Registry country fields are not a device location. A network's registered organization may differ from the consumer-facing ISP brand.
How to Use the ASN Lookup Tool
- Enter an ASN. Type the Autonomous System Number, with or without the AS prefix. For example,
AS17557and17557are both accepted. - Select Lookup ASN. The tool identifies the relevant Regional Internet Registry and requests the available registration record.
- Review the results. Check the network name, organization, registry, status, and other fields returned by the registry.
- Verify the source. Open the original RDAP record for additional information or use Copy Details to save the displayed results.
Only enter an ASN. This tool does not accept an IP address, domain name, or company name as a search input.
What Is an ASN?
An Autonomous System Number (ASN) is a numerical identifier used in internet routing. Networks such as internet service providers, hosting companies, cloud platforms, and large organizations use Autonomous Systems to exchange routing information.
The Border Gateway Protocol (BGP) helps independently operated networks communicate which IP address ranges they can reach. AS numbers identify the networks involved in that routing process.
For example, a network operator may use its ASN when exchanging routing information with another provider. The ASN helps identify the participating network, but it does not describe the speed or quality of an individual customer’s connection.
Both 16-bit and 32-bit AS numbers exist. Modern ASN notation commonly uses the AS prefix followed by a decimal number.
Understanding Your ASN Lookup Results
The tool displays the details available in the registration record. Not every registry provides every field.
| Result field | What it means |
|---|---|
| Autonomous System Number | The number you searched, displayed with the AS prefix |
| Registered ASN name | The network identifier recorded by the registry |
| Registered organization | The organization information available in the registration data |
| Regional Internet Registry | The registry responsible for the ASN record |
| Registry handle | A reference identifier assigned to the registration |
| Registration range | The ASN or range of ASNs covered by the record |
| Registry country code | The country code recorded for the registration, when supplied |
| Registration status | The status reported in the registry record |
| Registration date | The date recorded for registration, when available |
| Registry record updated | The most recent relevant update date provided by the registry |
| Data retrieved | The timestamp attached to the lookup response |
A missing field does not automatically indicate an invalid ASN. It may simply mean the registry did not supply that information.
Important: The registration range describes AS numbers, not the IP address prefixes announced through BGP.
Where Does the ASN Information Come From?
Our ASN Lookup uses the Registration Data Access Protocol (RDAP), a standardized method of retrieving internet registration records.
The tool uses the Internet Assigned Numbers Authority (IANA) ASN allocation information to identify the appropriate Regional Internet Registry.
The five Regional Internet Registries are:
- APNIC: Asia Pacific Network Information Centre
- ARIN: American Registry for Internet Numbers
- RIPE NCC: Regional registry serving Europe, the Middle East, and parts of Central Asia
- AFRINIC: African Network Information Centre
- LACNIC: Latin America and Caribbean Network Information Centre
Pakistan falls within APNIC’s service region. However, users can search AS numbers assigned through any of the five registries.
Registry results may be cached, so a recently changed record may not appear immediately.
Public, Private, and Reserved AS Numbers
Not every number within the valid ASN range identifies a publicly registered network.
IANA maintains reservations for several purposes. Two ranges are designated for private use:
| ASN range | Classification |
|---|---|
| 64512–65534 | Private-use ASNs |
| 4200000000–4294967294 | Private-use ASNs |
Private-use ASNs are intended for routing arrangements where globally unique public AS numbers are not required. They should not be treated as identifiers of a unique public network.
Other ASNs are reserved for documentation, special functions, or protocol compatibility.
The lookup tool can identify supported special-use ranges instead of displaying ordinary public registration results.
ASN Lookup for Pakistani Internet Networks
ASN information is useful when researching internet providers and network infrastructure in Pakistan.
For example, network administrators, IT students, and technically interested users may use it to examine the registration details of networks associated with PTCL and other Pakistani connectivity providers.
It can help answer questions such as:
- Which organization is recorded for a particular ASN?
- Which Regional Internet Registry maintains its record?
- What country code and registration status are available?
- Where can I verify the original network registration?
However, the registered organization is not necessarily the brand shown on a customer’s internet bill. A provider may use different legal entities, network operators, or infrastructure arrangements.
An ASN lookup also cannot establish whether a particular home internet connection is currently using that network.
What an ASN Lookup Cannot Tell You
ASN registration data is useful, but it has limits.
It does not measure internet speed. Download speed, upload speed, latency, and packet loss require separate testing.
It does not establish live BGP activity. A registered ASN is not proof that the network is currently announcing internet routes.
It does not locate an individual user. A registry country code is not a GPS position, server location, or reliable indication of a customer’s physical address.
It does not list live IP prefixes. Identifying currently announced prefixes requires routing information from suitable BGP data sources, not registration records alone.
It does not automatically identify your own ASN. You must enter the ASN you want to investigate.
For reliable conclusions, interpret the registration details alongside other relevant network information.
Why Is My ASN Lookup Not Working?
If a lookup fails or returns no registration record, check the following:
Incorrect number: Enter digits only, optionally preceded by AS. Remove spaces, punctuation, and unrelated text.
Out-of-range value: The tool accepts numbers from 1 through 4294967295, although some values are reserved or unallocated.
Unallocated or reserved ASN: The requested number may not correspond to an ordinary public registry assignment.
Missing registry record: A registry may not return a usable record. This does not necessarily prove the ASN has never been assigned.
Temporary registry problem: An RDAP service may be unavailable or limiting requests. Try again later.
For important investigations, use the original RDAP source link to review the available registration information.
Frequently Asked Questions
Can I look up any ASN worldwide?
The tool is designed to query the five Regional Internet Registries. Results depend on ASN allocation information, registry availability, and the records returned.
Is ASN lookup free?
The NetTools Pakistan ASN Lookup does not require visitors to purchase an API subscription or create an account to submit a lookup.
Is an ASN the same as an IP address?
No. An IP address identifies an interface or endpoint in an IP network, while an ASN identifies an Autonomous System for routing purposes. A network can originate routes to multiple IP address ranges using the same ASN.
Can an ASN tell me which ISP I am using?
An ASN can help identify a network operator when you already know which ASN is associated with your connection. However, entering an ASN alone does not establish your current ISP or connection path.
Official Technical References
- IANA Autonomous System Numbers Registry
- IANA Special-Purpose AS Numbers
- IANA RDAP Bootstrap Registry for AS Numbers
- RFC 9083 – RDAP JSON Responses
- RFC 6996 – Autonomous System Numbers for Private Use