whatismynetip

io.github.getlarkwrightPublished by GitHub account getlarkwrightv0.1.1Updated Nov 7, 2026

Subnet math, port and MAC lookups, DNS, DNSBL, TLS cert inspection, public IP. No account.

VerifiedSTDIODesktop onlyCloud & InfrastructureDeveloper ToolsSecurity & Monitoring

Overview

AI-generated overview

A local network toolbox for coding agents: subnet math, IP conversion, MAC vendor lookup, port exposure advice, DNS, DNSBL, TLS certificate and public IP…

What you can do
  • Calculate subnets and check whether an address falls inside a CIDR block, for IPv4 and IPv6
  • Convert IPv4 between dotted, integer, hex and binary forms, and normalize IPv6 addresses
  • Look up MAC address vendors from a bundled IEEE table, and look up what runs on a port plus whether it should be exposed
  • Resolve DNS records and reverse DNS over DNS-over-HTTPS, and check addresses against common blocklists
  • Inspect the TLS certificate a host actually serves, and report the public IP, ASN and edge location the internet sees
When to use it
Useful when an agent is helping with network configuration, firewall or exposure reviews, DNS troubleshooting, certificate expiry checks, or answering questions like whether a port should be open to the internet.
Requirements
Runs locally over stdio. Either Node.js 18 or newer for the npx route, or Docker for the container image. No account, API key or environment variables. Network access is needed only for the DNS, blocklist, TLS and public IP tools; the calculators and lookups work offline.
Before you install
The network tools contact public third-party services (Cloudflare DNS-over-HTTPS and trace, Google DNS-over-HTTPS, Team Cymru ASN DNS) and the host you point the TLS inspection at, so queried hostnames and addresses leave your machine. TLS inspection refuses private or reserved addresses. It cannot test whether a port is reachable from outside your NAT.

Installation

In SourceWeft

  1. Open whatismynetip in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

netip-mcp

The whatismynetip.com toolbox as tools your coding agent can call. Subnet math, "what runs on this port and should it be open", MAC vendor lookups, DNS and blocklist checks, the certificate a host actually serves, and the IP the internet sees you as.

Free, MIT, no account, no telemetry. The site's own tools run in your browser; this runs the same logic next to your agent.

Install

Pin the version.

Claude Code

claude mcp add netip -- npx -y github:getlarkwright/netip-mcp#v0.1.1

Claude Desktop, Cursor, or any client with a JSON config

json
{  "mcpServers": {    "netip": {      "command": "npx",      "args": ["-y", "github:getlarkwright/netip-mcp#v0.1.1"]    }  }}

Docker

json
{  "mcpServers": {    "netip": {      "command": "docker",      "args": ["run", "-i", "--rm", "ghcr.io/getlarkwright/netip-mcp:0.1.1"]    }  }}

Node 18 or newer for the npx route. Also in the official MCP registry as io.github.getlarkwright/netip-mcp.

Tools

ToolWhat it answersNetwork
subnet_calcNetwork, mask, wildcard, broadcast, host range and counts for a CIDR — IPv4 and IPv6, /31 and /32 done rightnone
ip_in_subnetIs this address inside that block?none
ip_convertIPv4 as dotted, integer, hex, binary — from any of themnone
ipv6_normalizeExpanded and RFC 5952 compressed forms, and what kind of address it isnone
mac_lookupVendor from the full IEEE registry (~40,000 assignments, bundled), plus the multicast and locally-administered bitsnone
lookup_portWhat runs on a port, and whether to expose it — 100 ports written up by hand, searchable by servicenone
dns_lookupA, AAAA, MX, TXT, NS, CNAME, CAA, SOA, PTR, SRV over DNS-over-HTTPSDoH
reverse_dnsPTR for an IPv4 or IPv6 addressDoH
dnsbl_checkFive common blocklists, honest about the ones that refuse public resolversDoH
tls_inspectThe certificate a host actually serves: expiry, SANs, chain verification, protocol, cipherdirect TLS
my_public_ipThe address the internet sees, edge location, ASN, reverse DNS, datacenter/VPN hintCloudflare trace + Team Cymru DNS

lookup_port

The one I reach for most. The port pages on the site are opinionated — every port carries a verdict:

Port 3389/tcp+udp — RDP (Remote Desktop Protocol)
  Category   remote access  Software   Windows Remote Desktop Services, xrdp, FreeRDP server, Windows Admin Center hosts  Exposure   NEVER — do not expose to the internet
Internet-facing RDP is the most common initial-access route for ransomware crews, whocredential-stuff it around the clock; put it behind WireGuard, Tailscale or an RD Gateway …

Ask by number, or search: lookup_port with query: "redis" finds 6379. detail: true adds the full write-up and FAQ.

What it does not do

  • No account, no signup, no key.
  • No telemetry. Nothing about your usage goes anywhere.
  • Nothing of yours is read from disk. The only file it opens is its own bundled OUI table.
  • The local tools never open a socket. The network tools talk only to public services — Cloudflare and Google's DNS-over-HTTPS resolvers, Cloudflare's trace endpoint, Team Cymru's ASN DNS, and whichever host you point tls_inspect at. tls_inspect refuses anything that resolves to private or reserved space, so it cannot be turned on your own network.
  • "Is my port reachable from outside?" needs a machine outside your NAT to try the connection. That is what whatismynetip.com/port-checker does; a local tool cannot.

The port data and the calculators are the same ones the site uses, so the two stay in step.

Licence

MIT © Larkwright LLC. Written by James Son — network, security, and automation engineer. Corrections and additions to the port write-ups are welcome.

Source: README.md at commit d422005

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v0.1.1LatestNov 7, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts