Webservice to map IP addresses to AS information.
This is the source code of the public API from iptoasn.com.
Requires rust.
$ curl https://api.iptoasn.com/v1/as/ip/<ip address>
{
"announced": true,
"as_country_code": "US",
"as_description": "LEVEL3 - Level 3 Communications, Inc.",
"as_number": 3356,
"first_ip": "4.0.0.0",
"ip": "4.3.2.1",
"last_ip": "4.23.87.255"
}