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FernTool Network Tools
com.ferntool/ip in the official MCP registry.
Endpoint https://www.ferntool.com/mcp.
The registry describes it as: 24 free tools: IP/VPN lookup, WHOIS, DNS, SPF/DMARC, site up/down, redirects, time zones. No key.
We read its 25 tools on 2026-10-31. Nothing in them matched our tool-poisoning rules. It also sets server instructions, text a client puts in front of the model on connect; those were read too.
A clean read means these rules found nothing, not that the server is harmless. A server can change its tools at any time, which is why the index reads it again every week.
Connect it
The endpoint answers MCP over HTTP; that is how we read it. Add it to your client:
claude mcp add --transport http ip https://www.ferntool.com/mcp{
"mcpServers": {
"ip": {
"url": "https://www.ferntool.com/mcp"
}
}
}code --add-mcp '{"name":"ip","type":"http","url":"https://www.ferntool.com/mcp"}'Some servers ask you to sign in the first time a client connects, or want a key from the people who run them; the server's own docs say which.
Let Claude Code check servers as it adds them
With the free lazaretto-guard plugin installed, when Claude Code adds a server for you or writes one into an MCP config, the plugin reads the server's tools first and asks you if one of our rules matches. Install it, restart Claude Code, then ask it to run the command above.
claude plugin marketplace add jamesdfinance-dev/lazaretto-plugins
claude plugin install lazaretto-guard@lazaretto-pluginsTools it advertises
get_my_ip lookup_ip validate_ip batch_lookup_ip whois_lookup dns_lookup reverse_dns subnet_calc estimate_ai_cost make_qr_code count_words get_current_time convert_timestamp date_calc convert_timezone random_number pick_random check_dns_propagation check_email_security check_website_status trace_redirects check_website_legit analyze_email_headers generate_spf_record ai_service_status
Tool changes
We compare every full read of this server with the one before. No change in what its tools say has been seen since we started keeping this record on 2026-10-30.
Fingerprint of its tools at our last full read (2026-10-31):
9c77e60ded14f34a. A client can hash the tools it is served the same way and compare;
the full value and a hash per tool are in this page as JSON.
Run this server? Show the check in your README
The badge reflects the latest weekly read:
[](https://lazaretto.dev/mcp-registry/com-ferntool-ip)How this was checked
Lazaretto connects to the endpoint the way any MCP client does, asks the server to introduce itself and list its tools, and reads every name, description, parameter schema and server instruction for tool poisoning: hidden directive blocks, orders to read local secrets, parameters built to carry secrets or the conversation out, orders that redirect another server's tools, and invisible characters. It never calls a tool. What we found across the registry.
To run the same check every time Claude Code adds a server, install the free lazaretto-guard plugin. Browse every server in the index.