qBittorrent-NatMap

The objective of this container is to run a script that requests a port forward (via NAT-PMP) from the VPN provider and upon success changes the listening port of the qBittorrent client when running in Docker

This solution is currently in use and tested with Gluetun and qBittorrent from Linuxserver.io and with VPN fron ProtonVPN using Wireguard.

What made me do this?

The need to improve the seeding/upload performance and not finding any work done for this scenario (qBittorrent using docker'ized VPN), but finding this post on reddit by u/TennesseeTater for Deluge made me try and do something similar. His post is also referenced in the ProtonVPN Guide.

Why not modify the Gluetun image and include natpmpc there?

Well, as far as I could find, Alpine Linux doesn't have natively the binary for natpmpc, the NAT-PMP client used to request the port forward as per the instructions for manual mapping on ProtonVPN. Gluetun is using alpine as it's base image.

On AlpineLinux package info: natpmpc binary not found and here a request still in open state.

If I had the binary needed on the Gluetun container a script running on the host system instead of the container would probably suffice, allowing the following action: doing "docker exec natpmpc "

What does the script do/modify?

So far:

• Evaluates the required variables for execution (for now, if they're set) and if docker.sock was mapped from the host into the container
• If the above succeeds:
  • Get the VPN public IP
  • Grab the SessionID cookie from qBittorrent
  • Grab the current listen port from qBittorrent
• After the configured checks pass, a function to request and verify the port mapping starts
  • Using natpmpc a port mapping request is made to the address defined in VPN_GATEWAY for udp and tcp
  • Comparison is made between the current configured port in qBittorrent and the currently active mapped port from the VPN
  • If a condition of different port is found:
    • The new port is configured in qBittorrent, along with that it's also disabled the random port setting and UPnP mapping from the torrent client
    • A couple of commands are executed to add/remove iptables rules regarding the previous active and new active mapped port on the VPN container

These actions are performed continuously (in a loop, every 5 minutes (default, can be lowered/increased)), most likely an option to set a failure count will be added in the future.

Configurable variables:

• QBITTORRENT_SERVER (Defaults to empty, needs to be set)
  • If setting here an address not related to the VPN_IF_NAME (default: tun0) a few users have reported needing to set FIREWALL_OUTBOUND_SUBNETS for the Gluetun/VPN container
  • For ProtonVPN using Wireguard and qBittorrent container using VPN_CT_NAME as network_mode this would be set to 10.2.0.2
• QBITTORRENT_PORT (Defaults to 8080)
• QBITTORRENT_USER (Defaults to admin)
• QBITTORRENT_PASS (Defaults to adminadmin)
• VPN_GATEWAY (Defaults to empty, needs to be set)
  • The value for this variable will be the VPN_IF_NAME (default: tun0) gateway address, not the VPN_ENDPOINT_IP from the Gluetun/VPN Container when using Wireguard, more info here.
  • For ProtonVPN using Wireguard this would be set to 10.2.0.1
• VPN_CT_NAME (Defaults to gluetun)
• VPN_IF_NAME (Defaults to tun0)
• CHECK_INTERVAL (Defaults to 300s)
• NAT_LEASE_LIFETIME (Defaults to 300s)
  • Ideally both CHECK_INTERVAL and NAT_LEASE_LIFETIME should be set equal or the check interval lower than the lease lifetime, but never above.