Table of Contents
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:
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