Table of Contents

• Table of Contents
• fwd - The little forwarder that could
  • About
  • Use Cases
    • fwd ♥️ ngrok
    • Simple Use Case
  • Install
    • Binary Releases
    • Go Tool
  • Usage
  • Credits

fwd - The little forwarder that could

About

fwd is a network port forwarder written in golang.

It's cross platform, supports multiple architectures and it's dead simple to use.

Read all about it in this article.

Use Cases

fwd ♥️ ngrok

I must admit ngrok was an huge inspiration for fwd. If you don't know the tool you should definitely check out this talk from @inconshreveable.

This tool combo (fwd + ngrok) allows some wicked mischief, like taking firewall hole punching to another level! And the setup is trivial.

ngrok allows to expose a local port on a public endpoint and fwd allows to connect a local port to a remote endpoint. You see where I'm heading with this... With both tools you can connect a public endpoint to a remote port as long as you have access to it.

Here's how it works:

                              +---------+                            +---------+
                        :9000 |         |            172.28.128.3:22 |         |
Internet +------------------> |   fwd   | +------------------------> |   ssh   |
tcp.ngrok.io:1234             |         | 172.28.128.1               |         |
                              +---------+                            +---------+

# get a public endpoint, ex: tcp.ngrok.io:1234
ngrok tcp 9000

# forward connections on :9000 to 172.28.128.3:22
fwd --from :9000 --to 172.28.128.3:22

# get a shell on 172.28.128.3 via a public endpoint
ssh tcp.ngrok.io -p 1234

With great power comes great responsibility. - Ben Parker

Simple Use Case

Forwarding a local port to a remote port on a different network:

                             +---------+                             +---------+
           192.168.1.99:8000 |         |             172.28.128.3:80 |         |
curl +---------------------> |   fwd   | +-------------------------> |   web   |
                             |         | 172.28.128.1                |         |
                             +---------+                             +---------+

Install

Get the binaries or build it yourself.

Releases

Download prebuilt binaries for several platforms and architectures:

Releases

Go Tool

go get github.com/kintoandar/fwd/...
go install github.com/kintoandar/fwd/...

Usage

usage: fwd [<flags>]

Name:

  fwd - 🚂 The little forwarder that could

Author:

  Joel Bastos @kintoandar

Example:

  fwd --from localhost:8000 --to example.com:80

Flags:
  -h, --help                   Show context-sensitive help (also try --help-long and --help-man).
  -f, --from="127.0.0.1:8000"  Local address to bind port (host:port)
  -t, --to="example.com:80"    Remote address to forward traffic (host:port)
  -v, --version                Version details
  -l, --list                   List local network addresses available
      --log.level=info         Logging level (error, warn, info, debug)
      --log.format=logfmt      Logging format (logfmt, json)
      --config=CONFIG          Configuration file path (overrides all flags)

Configuration file

For multiport forwarding support, please check the example configuration file.

Credits

Made with ♥️ by kintoandar