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IPv4 cache refreshed 9 hr ago  ◆  IPv6 cache refreshed 8 hr ago  ◆  Prefixes in table 1,107,739 v4 · 261,906 v6  ◆  Peers 91 v4 · 20 v6  ◆  whois.pwhois.org:43 answering  ◆ 
Prefix WhoIs The Prefix
WhoIs Project
mcp·free·private·no account required

Give your AI assistant the routing table and registries.

pWhoIs MCP puts the resources of Prefix WhoIs inside Claude, Cursor and any model context protocol (“MCP”) client. Ask who announces an address, what an AS originates, or who is knocking in a log, and the assistant answers from the live global BGP table, enriched with registry and geo data. The same service we have run since 2005. Connect once. No account, no email, no API key. And private: like the whois service itself, we do not keep what you ask about.

Connect in one minuteSee the tools
setup

Connect once. Ask forever.

Add the connector from your assistant. A page opens in your browser with a single Connect button. Press it and you are done.

  1. Open Settings, then Connectors.
  2. Choose Add custom connector.
  3. Paste https://pwhois.org/mcp/ and press Add.
  4. Press Connect. A browser page opens; press Connect there too.
  5. Start a chat and ask about any address.
https://pwhois.org/mcp/
tools

Example questions the MCP can answer.

Each tool costs a fixed number of queries from your daily allowance. The assistant sees the same costs, so it can plan a batch instead of guessing.

pwhois_lookup_ip1 query

One address, the full record

Origin AS, most-specific prefix, AS path, organization, network name, country and route age for a single IPv4 or IPv6 address.

try “Who announces 45.148.10.77 and how long has that route existed?”

pwhois_lookup_ips1 per address

Enrich thousands of addresses at once

Thousands of addresses in one call, clustered by origin AS and country, so a log becomes a short list of networks. Full records for up to 500 at a time; summaries for up to 5,000; the assistant chains calls for more.

try “Who is knocking on port 22 in this log? Group by network.”

pwhois_asn_info1 query

Who an AS is

Organization, country and registration details for an autonomous system, and how many prefixes it originates right now.

try “What is AS27552 and where is it based?”

pwhois_asn_prefixes1 per family

What an AS originates

Every prefix the AS is announcing right now, IPv4 or IPv6, with AS paths.

try “List the IPv6 prefixes AS13335 originates.”

pwhois_asn_transit1 query

What passes through an AS

Prefixes seen transiting the AS, with each origin, for mapping upstreams and downstreams.

try “Which prefixes transit AS6939 in the current table?”

pwhois_prefix_routes1 query

Routes covering a prefix

The active routes for a CIDR block: the best path, or every route-server view when you ask for all.

try “Show me the routes for 8.8.8.0/24 and who announces them.”

pwhois_org_search1 query

Find networks by name

Organizations on record whose name contains your text, with their AS numbers and announced prefixes.

try “Which ASes belong to organizations named Hurricane Electric?”

pwhois_registry_record1 query

The filing beside the fact

The registry record for an organization ID, an AS number or a contact handle, with abuse and technical contacts.

try “Pull the registry record for AS3356 and give me the abuse contact.”

pwhois_routing_statusfree

How fresh the table is

Table size, peer count and when the current cache was built.

try “How current is the routing data you are using?”

pwhois_my_quotafree

What you have left

Remaining daily allowance for the address you are connecting from, and when it resets.

try “How many pwhois queries do I have left today?”

fair use

Batch, don’t loop.

Queries share the daily allowance of the network address you connect from: 5,000 per day by default, the same allowance the classic whois service gives. Addresses already granted a higher limit keep it here too. The allowance resets at 00:00 UTC.

When the allowance runs out, the tool returns a structured quota_exhausted error with the reset time. Assistants read it and stop instead of retrying, so a runaway loop cannot burn through tomorrow’s budget.

  • Use pwhois_lookup_ips for lists. One call of 3,000 addresses costs the same as 3,000 single lookups but finishes in one round trip.
  • Ask the assistant to deduplicate addresses before looking them up. Repeats cost the same as new ones.
  • Call pwhois_my_quota before a large job, not after.
  • Higher limits are customarily granted free upon reasonable request for most uses, including education, research, security teams and government. Ask on the request form.
PRIVATE

No registration. No record of what you ask.

Nothing to sign up for and nothing to hand over. What you look up is answered and forgotten, exactly as it is for a whois query on port 43. All that is kept is the network address a connection was made from, so it can share that address’s allowance, and aggregate counts like the ones on the Stats page. Details in the privacy notice.

NEED MORE?

Need more than 5,000 a day?

Tell us who you are, what you are doing and which addresses you connect from. Education, research, security and government use is customarily granted a higher allowance, free, upon reasonable request.

Request a higher limit
in use

What assistants are asking.

The last 30 days of connector traffic statistics.

calls per day

Tool calls, last 30 days

tool calls
queries charged
tool mix

Which tools get used

lookup ip22.1%
registry record17.1%
prefix routes13.2%
lookup ips12.8%
asn prefixes8.9%
my quota8.2%
routing status4.5%
org search4.5%
asn transit4.5%
asn info4.5%
top 10 by country

Where the assistants connect from

1USUnited States49692.0%
—?Unknown438.0%
4.7k
addresses enriched
looked up through the connector in the last 30 days
98%
batched
of enriched addresses arrived in pwhois_lookup_ips batches rather than one at a time
8 ms
speed
median time to answer a tool call
documentation

What the assistant already knows.

Prompt: enrich_logPaste any text with addresses in it. The assistant extracts them, looks them up in one batch and returns a tally by origin AS and country, plus the addresses with no route in the table, honestly labeled.
Prompt: profile_asGive an AS number. The assistant gathers who it is, what it originates in each family and what transits it, then writes a short profile you can drop into a ticket.
Docs resourcesThree reference documents ship with the connection: a field guide to every record attribute, the tool and cost table, and the fair-use notes. The assistant can read them without spending a query.
Structured errorsEvery error names its cause. quota_exhausted carries the reset time; invalid input says what was wrong. Nothing to parse from prose.
Same answers as port 43A tool call and a whois query return the same record from the same table. Verify anything with whob or whois -h whois.pwhois.org.
DataAbout 1.1 million IPv4 and 262 thousand IPv6 prefixes from around 90 BGP peers, refreshed daily, plus registry and geo data from every regional Internet registry. Live figures on the Stats page.
questions

Quick answers.

Does it cost anything?

No. The connector is free, like the whois service it sits on. Higher limits are also free for most uses.

Do I need an account or an API key?

No. Add the connector, press Connect on the page that opens, and start asking.

How is the daily allowance counted?

By the network address you connect from. Assistant calls and classic whois queries from that address draw from the same 5,000. pwhois_my_quota shows the balance any time.

What happens when I run out?

Tools return a quota_exhausted error with the reset time. The assistant stops and tells you. The allowance returns at 00:00 UTC.

Which clients work?

Claude.ai custom connectors, Claude Desktop, Claude Code, Cursor and any MCP client that supports Streamable HTTP with OAuth.

How current is the data?

The routing table is rebuilt daily from around 90 peers. pwhois_routing_status reports when the current cache was built, at no cost.

Can I look up a whole log at once?

Yes. pwhois_lookup_ips takes up to 5,000 addresses in one call (500 when you want every individual record) and clusters them by origin AS and country; for bigger logs the assistant simply sends the next chunk. The enrich_log prompt does the extraction for you.

Is it private?

Yes. There is no registration, and what you ask about is not kept, the same as a whois query on port 43. The network address you connect from is remembered so your queries share its allowance, and usage is published only as aggregate percentages.

Is this the same data as whois.pwhois.org?

Yes. Same table, same records, same allowance. The connector is a new door into a service that has been open since 2005.