ASN Lookup by IP Address

What an ASN tells you

An autonomous system number identifies a network in internet routing. RIPEstat’s Network Info endpoint returns the prefix containing the queried address and the ASN or ASNs announcing that prefix, using RIPE RIS observations. A prefix is a group of addresses represented in routing data.

Use the result to identify a network path during troubleshooting. The announcing network can differ from a retail service brand or the customer renting an address. Click an ASN to inspect its RIPEstat profile. This tool does not add an inferred ISP name or guess whether a connection is residential.

How to look up the right address

First record the public address used by the affected application. What is my IP checks the browser’s IPv4 path. If the failing request runs in a cloud container or remote AI browser, obtain its address from that runtime instead.

Enter one IPv4 or IPv6 address without a port or subnet suffix. Compare the returned prefix and ASN with the configuration you intended. Keep the result and timestamp with the original error. An address lookup after a proxy rotation may describe a different route from the failed request.

Read missing or multiple announcements carefully

The API can return more than one announcing ASN; this page preserves them instead of selecting a preferred answer. A missing announcement means this query returned no route in the source’s view. It does not prove the address is safe, malicious or unused.

Private and reserved addresses are not ordinary public internet destinations. A local address copied from a device’s Wi-Fi settings is therefore different from the public address a website observes. If RIPEstat is unavailable, the tool reports the failure without substituting an ASN.

ASN classification is separate from reputation

A network identifier cannot establish an account’s standing or guarantee that a site accepts a request. A carrier ASN also does not prove an exclusive public address. Read the IP reputation guide before treating a network label as a trust score.

For an access failure, collect the response code and follow the IP-ban diagnosis workflow. A site owner’s matching log entry is more direct evidence of a denial than an unrelated network lookup.

Frequently asked questions