GeoLite2 ASN Database

Look up the autonomous system number and autonomous system organization associated with IPv4 and IPv6 addresses.

Data Privacy

To comply with data privacy regulations, please monitor our Do Not Sell My Personal Information Requests page (login required) for IP addresses and networks that should not be used for advertising or marketing purposes. You can automate retrieval of this list using our privacy exclusions API.

Binary Database

Binary databases make use of the MaxMind DB file format. MaxMind provides official client APIs in the language listed below. The following client APIs are open source and licensed under the Apache License, Version 2.0.

You can also use the mmdbinspect tool (in beta), a command line interface built with Go, to look up one or more IPs from one or more MMDB databases and receive output in a parsable JSON format.

CSV Database

In addition to our MaxMind DB binary format, we also offer GeoIP2 and GeoLite2 databases in a CSV format suitable for importing into a SQL database. The CSV files are shipped as a single zip file.

The zip file itself is named  GeoLite2-ASN-CSV_{YYYYMMDD}.zip. The downloaded zip file contains a single directory which in turn contains several files. That directory is named  GeoLite2-ASN-CSV_{YYYYMMDD}.

The files in this zip archive are:

LICENSE.txtEnd user license
COPYRIGHT.txtCopyright statement
GeoLite2-ASN-Blocks-IPv4.csvCSV file containing data on IPv4 addresses
GeoLite2-ASN-Blocks-IPv6.csvCSV file containing data on IPv6 addresses

All the CSV files start with a single header row containing column names. The specific column names and their contents are detailed below. The files are encoded as UTF-8.

Blocks Files

There are two CSV files for network blocks, one each for IPv4 and IPv6 blocks. These are named GeoLite2-ASN-Blocks-IPv4.csv and GeoLite2-ASN-Blocks-IPv6.csv respectively.





IP network as a string

This is the IPv4 or IPv6 network in CIDR format such as “” or “2001:4b0::/80”. We offer a utility to convert this column to start/end IPs or start/end integers. See the conversion utility section for details.



The autonomous system number associated with the IP address.

* Learn more about autonomous system data on our Knowledge Base.



The organization associated with the registered autonomous system number for the IP address.

* Learn more about autonomous system data on our Knowledge Base.

Conversion Utility

We've created a small utility program to allow you to convert a GeoIP2 CSV file's representation of IP addresses to another format. You can choose between start/end IP addresses, with the addresses represented as strings or integers.

The program is available from our geoip2-csv-converter GitHub project releases tab.

Example Files

We maintain example files in CSV and MMDB format. The files contain dummy data rather than real GeoIP data.

CSV Example Files

We maintain examples of the CSV files as they would be downloaded from the account portal:

MMDB Example Files

We maintain test MMDB files on GitHub:

Alternatively, you can view all of our MMDB test data on GitHub.

Database Sizes

MaxMind databases can vary in size from release to release. If you are working with file size limitations that are concerning, you should build your integrations to fail gracefully in event of a significant size change.

From March to June 2024, the database files varied in file size and number of networks as follows:

DatabaseCSV File SizeMMDB File SizeIPv4 NetworksIPv6 Networks
GeoLite ASN27.69 MB - 28.09 MB8.41 MB - 8.56 MB505,000 - 510,000131,000 - 137,000

The listed file sizes are for unpacked databases. Databases are downloaded in a compressed format.

Database Changes

We may add new data fields to the ASN database at any time.

New database fields are added as new columns to the right of existing columns in our CSV files, and as additional data in our MMDB files.

Subscribe to our GeoIP2 release notes to be notified when new data is added to our databases.

APIs and Third-Party Integrations

You can find a complete list of official and unofficial client APIs, and third-party integrations on the database documentation page.

This page was last updated on July 17, 2024.