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IPv4 cache refreshed 12 hr ago  ◆  IPv6 cache refreshed 10 hr ago  ◆  Prefixes in table 1,133,820 v4 · 264,555 v6  ◆  Peers 78 v4 · 20 v6  ◆  whois.pwhois.org:43 answering  ◆ 
Prefix WhoIs The Prefix
WhoIs Project
web lookup

Ask the routing table.

A demonstration of the public service, answered live from whois.pwhois.org. Pick what you want to ask about, watch the exact query take shape, and read the answer as the server sent it — or prettified. For anything scripted or bulk, query port 43 directly: it is built for volume, this page is not.

Ask about
output

Prefix WhoIs displays the origin-as and other interesting information related to the most specific prefix currently advertised within the Internet's global routing table that corresponds to the IP address in your query.

what this will send
$ whois -h whois.pwhois.org ""
$
Human check runs automatically. No automated querying of this page, please.

From your command line

Everything this page builds is an ordinary whois query — the first line in the preview above works in any whois client pointed at whois.pwhois.org. Our WhoB client adds the second line: -g parses the answer down to one line, and -e tags every address in whatever you pipe through it.

$ whois -h whois.pwhois.org 1.2.3.4 $ whois -h whois.pwhois.org "type=json 1.2.3.4" $ whois -h whois.pwhois.org "routeview source-as=3356" $ whois -h whois.pwhois.org "registry org-id=LPL-141"
$ whob -gnp 4.2.2.1 4.2.2.1 | origin-as 3356 (4.0.0.0/9) | as-path 8220 1299 3356 | LVLT-ORG-4-8 | Level 3 Parent, LLC $ echo "2001:4860:4860::8888 and [2606:4700:4700::1111]:53" | whob -e 2001:4860:4860::8888 [AS15169 Google LLC] and [2606:4700:4700::1111]:53 [AS13335 Cloudflare, Inc.]

Thousands at once — wrap a list in begin / end and pipe it in with netcat. Only the native and Cymru formats support bulk output.

$ netcat whois.pwhois.org 43 < ip_list.txt

Query etiquette

This page is a demonstration; do not script against it. The real service is port 43 and is built for volume: use bulk mode rather than one connection per address, cache answers for at least the Cache-Date interval, and prefer type=json if you are parsing.

Unregistered sources get a daily allowance sufficient for a few thousand queries. Need more? Tell us who you are and which static IPs you query from and we will very likely raise it — free for education, research and government use.

Request a higher limit Read the FAQ
+ registry record appends the address registry's allocation record beneath the routing answer — useful when you need both the allocation and the announcement. ▲ marks the large answers; the web shows their first 2,000 rows.