FernTool IP Lookup

Free remote MCP server to get your public IP, look up country, ISP and ASN for any IP, and validate IPv4/IPv6. No API key needed. Tools: get_my_ip, lookup_ip, validate_ip. Remote URL (streamable HTTP): https://www.ferntool.com/mcp

GitHub

Hosted MCP Server

npx add-mcp 'https://www.ferntool.com/mcp'

Installs into Claude Code, Codex, Cursor and more

Documentation

FernTool — network toolbox MCP server & free IP API

FernTool is a fast, clean "what is my IP" and IP lookup tool. This repo documents its hosted, remote MCP server so AI assistants and agents (Claude, Cursor, VS Code Copilot and others) can:

get the caller's public IP, ISP, ASN, location and timezone
look up the country, ASN and network owner of any IPv4/IPv6 address
detect Tor exit nodes, VPN/datacenter and cloud IPs (AWS, Google Cloud, Azure, Cloudflare, DigitalOcean, Oracle, Hetzner, OVH and more)
batch look up to 100 IPs in one call
run WHOIS (RDAP) for domains, IPs and ASNs, DNS lookups (A/AAAA/MX/TXT/NS/CNAME/SOA), reverse DNS and IPv4/IPv6 subnet math
validate and classify IP addresses (public, private, loopback, documentation and so on)

No API key, no install, no sign-up. It's just a URL:

https://www.ferntool.com/mcp

Transport: MCP streamable HTTP (JSON-RPC 2.0, protocol 2025-06-18).

Connect

Claude Code

claude mcp add --transport http ferntool https://www.ferntool.com/mcp

Claude Desktop (claude_desktop_config.json). Use Settings → Connectors → Add custom connector with the URL above, or bridge with mcp-remote:

{ "mcpServers": { "ferntool": { "command": "npx", "args": ["-y", "mcp-remote", "https://www.ferntool.com/mcp"] } } }

Cursor (~/.cursor/mcp.json or .cursor/mcp.json)

{ "mcpServers": { "ferntool": { "url": "https://www.ferntool.com/mcp" } } }

VS Code (.vscode/mcp.json)

{ "servers": { "ferntool": { "type": "http", "url": "https://www.ferntool.com/mcp" } } }

Ready-made files are in examples/.

Tools

Tool	Input	What it returns
`get_my_ip`	none	Public IP of the caller (IPv4 or IPv6) with ISP, ASN, city/region/country, coordinates, timezone and `is_tor` / `is_datacenter` / `provider`. For remote agents, this is the IP of the machine calling the server.
`lookup_ip`	`ip` (string, IPv4 or IPv6)	Validity, version, scope, country, timezone, ASN, network owner and `flags` (`is_tor`, `is_datacenter`, `provider`).
`batch_lookup_ip`	`ips` (array of 1–100 strings)	`lookup_ip` results for every address, plus `complete` / `retry`.
`validate_ip`	`ip` (string)	Whether it's a valid IPv4/IPv6, the expanded form and the scope (public/private/loopback/link-local/documentation/...).
`whois_lookup`	`query` (domain, IP or ASN like `AS13335`)	RDAP record: registrar, created/expiry/updated dates, status, nameservers, DNSSEC; for IPs/ASNs the network name, range/CIDR, owner org, country and abuse contact.
`dns_lookup`	`domain`, optional `types` (A, AAAA, MX, TXT, NS, CNAME, SOA)	Records with TTLs via Cloudflare 1.1.1.1 DNS-over-HTTPS, response status and DNSSEC validation flag.
`reverse_dns`	`ip`	PTR hostname(s) and whether the hostname resolves back to the IP (forward-confirmed).
`subnet_calc`	`cidr` (e.g. `192.168.1.0/24`, `2001:db8::/48`)	Network, netmask, wildcard, broadcast, first/last usable, total and usable addresses, block type.

Example lookup_ip result for 8.8.8.8:

{
  "valid": true, "version": 4, "ip": "8.8.8.8", "scope": "public",
  "source": "dbip-lite+iptoasn",
  "geo": { "country": "US", "country_name": "United States", "asn": 15169, "isp": "GOOGLE",
           "timezone": "America/New_York", "timezones": ["America/New_York", "..."] },
  "flags": { "is_tor": false, "is_datacenter": true, "provider": "Google Cloud" }
}

Example validate_ip result for 2001:db8::1:

{ "valid": true, "version": 6, "ip": "2001:db8::1",
  "expanded": "2001:0db8:0000:0000:0000:0000:0000:0001", "scope": "documentation" }

Raw JSON-RPC

curl -s https://www.ferntool.com/mcp \
  -H 'Content-Type: application/json' -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"lookup_ip","arguments":{"ip":"8.8.8.8"}}}'

Plain HTTP API

The same data is available without MCP. There's no key, and CORS is *. Full spec: /openapi.json.

curl https://www.ferntool.com/ip              # 203.0.113.7  (plain text)
curl https://www.ferntool.com/json            # your IP + ISP, ASN, city, timezone
curl https://www.ferntool.com/api/ip/1.1.1.1  # any IPv4/IPv6 (+ timezone, Tor/datacenter flags)
curl -X POST https://www.ferntool.com/api/batch -H 'Content-Type: application/json' -d '{"ips":["8.8.8.8","1.1.1.1"]}'
curl https://www.ferntool.com/api/whois/example.com          # RDAP WHOIS (domain, IP or ASN)
curl "https://www.ferntool.com/api/dns/example.com?type=A,MX" # DNS via Cloudflare DoH
curl https://www.ferntool.com/api/reverse-dns/1.1.1.1        # PTR
curl "https://www.ferntool.com/api/subnet?cidr=10.0.0.0/22"   # subnet calculator

Python:

import json, urllib.request
print(json.load(urllib.request.urlopen("https://www.ferntool.com/api/ip/8.8.8.8")))

JavaScript:

const r = await fetch("https://www.ferntool.com/api/ip/8.8.8.8");
console.log(await r.json());

Fair use

This is a free service on a shared edge network. Please cache results and keep traffic reasonable. Network lookups (WHOIS, DNS, reverse DNS, batch) are limited to roughly 40 per minute per IP; heavy or abusive traffic may be rate-limited further.

Data attribution

IP geolocation by DB-IP, licensed under CC BY 4.0.
ASN data from IPtoASN (PDDL).
The caller's own location in get_my_ip comes from the Cloudflare edge.
Tor exit list from the Tor Project; cloud ranges published by AWS, Google Cloud, Microsoft Azure, Cloudflare, DigitalOcean and Oracle; plus a list of well-known hosting ASNs. Refreshed regularly.
WHOIS from registry RDAP services (IANA bootstrap); DNS from Cloudflare 1.1.1.1. Timezones for other IPs are the country's main IANA zone (tzdata).

License

The contents of this repository (docs, examples, server.json) are under the MIT License. The hosted service and its data are subject to the attributions above.