pynat

DNAT port forwarding in pure Python

• asynchronous (uses non-blocking asyncore library)
• no dependencies
• compatible with PyPy

use case

• you need to forward ports from the executing machine to another hosts
  • e.g. you want to temporarily forward SSH to a NATed host through a Web server
• your application is multi-processed and it cannot be guaranteed that a process that created a port forwarding also closes it (but another process will do it)
  • this is true for most Web applications
• you don't want to grant you application rights to use iptables etc.
  • this would probably make the deployment less joyful and less secure
• you prefer few dependencies

installation

pip install [--user] git+https://github.com/lpirl/pynat.git

examples

a simple example including a test if the forwarding works

terminated the forwarding from within another process

todo

• a wrapper to conveniently set up a "process-agnostic" port forwarding (e.g. API as PortForwarding but returning the local port, the UNIX socket path and the secret)
  • thereby declutter this example
• ability to close established connections

feedback

Feel very free to contact me via issues/email etc. I'd be happy to hear if this actually works well in production/under load (sadly, my use cased vanished as I left the project I developed this for).