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IP to ASN

See the autonomous system number and network name that announce a public IP address.

This check runs on our server. The address you enter is used only for this check and is not stored.
Updated

This check runs on our server. The address you enter is used only for this check and is not stored.

How to use IP to ASN

  1. Enter a public IP address, or a host name.
  2. Tick the robot check and press Check.
  3. Read the ASN, the network name, and which address was checked.

How it works

This check runs on our server. The address is not stored.

RDAP for that address comes from the registry that holds the block. The page reads the origin autonomous system and the network name from that object, or from the autnum object the IP object links to. A private or reserved address is refused before any request, because it has no public announcement.

The ASN is the network that announces the address on the Internet. A site that sits behind a CDN shows the CDN's network, which can be a different organization from the one that wrote the pages.

Examples

  • 8.8.8.8 is announced by AS15169, Google.
  • A host name that resolves to one public address shows that address next to the ASN.
  • 192.168.0.1 is refused. It is a private address.

Limitations

  • One address per check. A name with both IPv4 and IPv6 uses the address the lookup selected, and the page names it.
  • The registry sometimes has the network name and no origin ASN. That row says the ASN was not in the record.
  • This does not place the address on a map.

Frequently asked questions

Is the ASN the owner of the website?

It is the network that announces the address. The site's operator can be a customer of that network, or of a CDN.

What about an address inside a larger block?

You get the announcement for the address you typed, which may be a more specific block than the parent range.

Do you store the address?

No.

Often used together with the IP to ASN.

  • Whois Lookup

    Registrar, domain status, name servers, and dates from the registry's RDAP record.

  • Ping

    Four pings from each available location, with the time of every packet.

  • Reverse DNS LookupDNS Tools

    PTR name for an IP address, plus a forward check that the name resolves back.