MCP server: connect your AI assistant

The Model Context Protocol (MCP) lets AI assistants such as Claude call tools and fetch live data. The server below is open: no account, no API key. It offers several tools behind one address.

Server and tools

Security research

One server with several read only lookup tools. Connect once and use all of them.

https://felix-pfeiffer.com/mcp

whois_lookupRegistration data of a domain via RDAP, with a WHOIS fallback: registrar, dates, statuses, name servers and DNSSEC.
Try: “When does example.com expire and who is its registrar?”
dns_recordsDNS records of a domain through public resolvers: A, AAAA, CNAME, MX, NS, TXT, SOA and CAA.
Try: “Which mail servers and SPF policy does example.com use?”

How to connect

Claude

Open Settings, then Connectors, choose Add custom connector and paste the server URL.

Claude Code

claude mcp add --transport http security https://felix-pfeiffer.com/mcp

Cursor

Add to ~/.cursor/mcp.json

{
  "mcpServers": {
    "security": {
      "url": "https://felix-pfeiffer.com/mcp"
    }
  }
}

VS Code

Add to .vscode/mcp.json

{
  "servers": {
    "security": {
      "type": "http",
      "url": "https://felix-pfeiffer.com/mcp"
    }
  }
}

Technical details

Transport: Streamable HTTP, stateless, JSON responses.
Authentication: none. Requests are rate limited per address.
Nothing you send is stored.
Source code on GitHub.

Questions

What is MCP?

MCP, the Model Context Protocol, is an open standard that lets AI assistants connect to tools and data sources through a common interface.

Do I need an account or API key?

No. The server on this page is free and open. It only limits how many requests one address can send per minute.

Are my requests stored?

No. A request is answered, cached for a few minutes and never saved.

Which assistants work with these servers?

Any client that supports remote MCP servers over Streamable HTTP, for example Claude, Claude Code, Cursor and VS Code.

By Felix Pfeiffer