GeoLite2 ASN CSV Database

In addition to our MaxMind DB binary format, we also offer the GeoLite2 ASN (Autonomous System Number) database in a CSV format suitable for importing into a SQL database. This documentation details the format of the CSV files. The CSV files are shipped as a single zip file.

Zip File

The zip file itself is named 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:

Filename Description
LICENSE.txt End user license
COPYRIGHT.txt Copyright statement
GeoLite2-ASN-Blocks-IPv4.csv CSV file containing data on IPv4 addresses
GeoLite2-ASN-Blocks-IPv6.csv CSV file containing data on IPv6 addresses

CSV File Format

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.

Name Type Description
network 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.
autonomous_system_number string The autonomous system number associated with the IP address.
autonomous_system_organization string The organization associated with the registered autonomous system number for the IP address.

Conversion Utility

We’ve created a small utility program to allow you to convert a GeoIP2 or GeoLite2 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.