ASN Lookup
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Who owns this IP? Who is AS4134? ASN Lookup gives every IP address and every AS number a page: the AS announcing it, the prefix holding it, the registry record, and for each AS every IPv4 and IPv6 prefix, its upstreams and downstreams, and the other ASNs of the same holder; its routing history: prefix counts over time, RPKI valid / invalid / no ROA, the latest prefixes it started or stopped announcing, and prefixes other ASes announce too.
Use it: https://asn.1ms.dog
More from 1ms.dog, all free and open source (hover a name to see what it answers)
IP & privacy: EgressLens · IP Quality Test · Who Are You · Streaming & AI Unlock Check
Speed & connectivity: 1ms.dog · Network X-Ray · Speed Test · DNS Test · Domain X-Ray · IPv6 Test · CDN Radar · Reach Check · Network Diagnosis · Route Trace · Global Ping
Cloud & costs: Me2Cloud · Lightsail Cost Saver · Cloud Cost Planner
Command line: httpslatency · vps2cloud · dnstest
What you get
- Any IP or prefix (
/ip/8.8.8.8, /ip/1.0.0.0/24): the AS announcing it, the announced prefix holding it, the range, the country; the registry's RDAP record (network name, organization, abuse e-mail) and reverse DNS; the prefix's RPKI state, since when it is announced and other ASes announcing it now or before. A link to Reach Check tests whether it can be reached from around the world.
- Any AS (
/AS4134): name, holder, country, registry and allocation date; how many prefixes and addresses it announces; every prefix (copy them all in one click, for a firewall or proxy rules); the upstreams, downstreams and peers RIPE's collectors see; other ASNs of the same holder.
- A domain: type it in the search box and it is resolved, then looked up.
- A word of a name (
/find?q=cloudflare): every network whose name, or the company holding it, carries the word, biggest first. A bare word in the search box goes there; AS2.0 (asdot) is read as AS131072.
- Browse (
/country, /country/CN, /rir/apnic): the countries with their flags, filterable by continent and by name; and a country's or a registry's networks, biggest first.
- Leaderboards (
/top): who holds the most addresses, who announces the most prefixes, the oldest and the newest allocations, and who co-announces the most prefixes.
- Today (
/today): the routing table as RIPE's collectors saw it on the last daily run — routes announced, what appeared and what went since the run before, RPKI ROAs, networks announcing anything, and the newest allocated networks.
- Prefixes several networks announce (
/moas): the IPv4 prefixes with more than one origin AS.
- Tools (
/tools): look up a list of addresses or AS numbers at once, with CSV to download, and merge a pile of prefixes into the shortest CIDR list. Both run in your browser; nothing is sent to our server.
- Your own IP: the home page shows the AS and prefix of your connection, with an RPKI coverage line for it.
The AS page also carries a health line: RPKI coverage, how much of its announcement a strict validator (RFC 6811) would drop, prefixes another AS announces too, whether it announces IPv6, the year its block was allocated, and whether one upstream carries it alone. The address page says which registry allocated the block and when.
Every AS page is rendered on the server, complete in the HTML, in 10 languages, and listed in the sitemaps (about 88,000 routed ASes).
This is the beginning of the README. Read the rest at the original. Read the full README ↗
