# heiher/natmap

TCP/UDP port mapping for full-cone NAT

Repository: https://github.com/heiher/natmap
Canonical: https://ross.abutalabs.com/products/natmap
Language: C
License: MIT
License Family: permissive
Topics: bsd, linux, macos, nat1, port-mapping, tcp, udp, windows
Last push: 2026-08-09T16:23:29+00:00

## Health v2 (maintenance only)
Score: 84/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 96, release rhythm 58, longevity 100
- inputs: {"age_days": 1432, "days_push": 24, "days_rel": 200, "gap_med": 55, "n_releases_24m": 8}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1950, forks 149 (observed 2026-08-28T04:05:58.119873+00:00)

## What it is
NATMap is a C-based CLI tool that establishes TCP/UDP port mappings from an ISP NAT public address to a local private address using STUN and HTTP keep-alive techniques. It works when all NAT layers are full-cone (NAT-1), enabling external access to internal services.

## Use cases
- expose a home server behind carrier-grade NAT to the internet
- map a public TCP/UDP port to a local private service
- discover the public mapped address via STUN and update DNS automatically
- run self-hosted services when the ISP uses full-cone NAT
- keep NAT port bindings alive with periodic keep-alive traffic

## When to choose
- your ISP NAT is full-cone (NAT-1) and you want direct inbound access without a relay
- you need a lightweight native tool with bind mode where traffic bypasses the program
- you want automatic notification of the mapped public address via a callback script

## When to avoid
- your NAT is symmetric or restricted-cone, where full-cone mapping cannot be established
- you need NAT traversal across arbitrary network conditions; use a VPN or tunnel like WireGuard or frp instead
- you require encrypted tunneling rather than plain port mapping

## Facets
- artifact type: cli-tool
- maturity: active
- function: networking, proxy, developer-tools
- domain: networking, self-hosted, privacy
- platform: windows, bsd, cli
- tags: nat-traversal, full-cone-nat, port-mapping, stun, hole-punching, linux, macos, android

## Member repositories
- heiher/natmap (main) score 84

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:58.119873+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:06:52.248646+00:00, confidence not recorded.
  - readme: https://github.com/heiher/natmap (fetched 2026-08-28T04:05:58.119873+00:00, sha 4c217fd2d8b5)
- Data as of 2026-08-30T08:39:29.467469+00:00.