dns-mcp

A Model Context Protocol server that lets any MCP client (Claude Desktop, Claude Code, Cursor, etc.) do DNS, WHOIS, and IP geolocation lookups mid-conversation.

Ask Claude "why is foo.com unreachable from Tokyo?" and it can actually dig the records, check the WHOIS, and geo-locate the IP without leaving the chat.

Features

• resolve_dns — forward lookup via DNS-over-HTTPS (A, AAAA, CNAME, MX, TXT, NS, SOA, PTR, SRV, CAA)
• reverse_dns — PTR lookup for IPv4 or IPv6
• whois_domain — structured registration info via RDAP (modern WHOIS)
• geo_ip — country / city / ASN / ISP for a public IP
• Bulk / zone transfer queries
• DNSSEC validation output
• Local cache (reduce repeated upstream calls)

No API keys required. All four tools hit public free endpoints:

Tool	Upstream
resolve_dns, reverse_dns	dns.google (DNS-over-HTTPS, JSON)
whois_domain	rdap.org (RDAP bootstrap, redirects to TLD registry)
geo_ip	ip-api.com (HTTP, 45 req/min free tier)

Quick Start

Install

pipx install dns-mcp
# or
uv tool install dns-mcp

Claude Desktop

Add to claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\):

{
  "mcpServers": {
    "dns": {
      "command": "dns-mcp"
    }
  }
}

Restart Claude Desktop; the four tools should show up in the tool menu.

Claude Code

claude mcp add dns dns-mcp

Codex CLI

Add to ~/.codex/config.toml:

[mcp_servers.dns]
command = "dns-mcp"

Restart Codex. The four tools are then available in any Codex session.

Run from source

git clone https://github.com/r0bin2u/dns-mcp && cd dns-mcp
uv sync
uv run dns-mcp

Example Prompts

• "What are github.com's A and MX records?"
• "Who registered cloudflare.com and when does it expire?"
• "Geolocate 140.82.121.4 — which country and ISP?"
• "My users in Tokyo say foo.com is slow. Resolve it, then geo-locate the IP."
• "I got an email from support@paypa1-security.com. Is that domain suspicious?"

Development

uv sync
uv run pytest
uv run ruff check .

Interactive debugging with the MCP Inspector:

npx @modelcontextprotocol/inspector uv run dns-mcp

A note on ip-api.com

The free tier of ip-api.com requires HTTP (not HTTPS). This is fine for geolocating arbitrary public IPs — no credentials are sent — but it means the request is visible on the wire. If that's a concern in your environment, swap in a HTTPS alternative (e.g. ipwho.is, ipinfo.io with a token) by editing IPGEO_URL in src/dns_mcp/__init__.py.

License

MIT — see LICENSE.