Port forwarding does not work with latest versions based on alpine 3.13+

[doman18]

Despite of proper port exposed by container and proper port forwarding set on router and positive result from https://www.yougetsignal.com/tools/open-ports/ in transmission GUI port is marked as Closed.
When downgraded to 3.00-r0-ls75 (last version based on alpine 3.12) port forwarding starts to work fine. No additional steps needed.
Additional info (maybe usefull?):
I had issuses with 3.13+ when tried to use it as base for my ipmitools project. It had issues with recognizing host DNS and thus could not install any additional packages. Downgrading to 3.12 helped too.

Steps to Reproduce

Just pull image with :latest tag or without tag at all.

Environment

OS: Raspbian
CPU architecture: arm64
How docker service was installed:
From convenience script, according to official docker documentation
Docker version 20.10.7, build f0df350

curl -fsSL https://get.docker.com -o get-docker.sh
sudo ./get-docker.sh 2>&1 | tee -a get-docker.log

Command used to create docker container (run/create/compose/screenshot)

docker-compose up -d

docker-compose.yml

# https://hub.docker.com/r/linuxserver/transmission

version: "2.1"
services:
  transmission:
    image: ghcr.io/linuxserver/transmission:3.00-r0-ls75
    container_name: transmission
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=Europe/Warsaw
    volumes:
      - ${TRANSMISSION_VOLUME_CONFIG}:/config
      - ./settings/settings.json:/config/settings.json
      - ${TRANSMISSION_VOLUME_DOWNLOADS}:/downloads
      - ${TRANSMISSION_VOLUME_WATCH}:/watch
    ports:
      - ${TRANSMISSION_EXTPORT_WEB}:9091
      - ${TRANSMISSION_EXTPORT_TCP}:51413
      - ${TRANSMISSION_EXTPORT_UDP}:51413/udp
    restart: always
    networks:
      - 'rev_proxy_net'
  
networks:
  rev_proxy_net:
      external:
        name: ${PROXY_NETWORK}

.env

TRANSMISSION_VOLUME_CONFIG=/home/pi/volumes/transmission/config
TRANSMISSION_VOLUME_DOWNLOADS=/mnt/sda1/volumes/transmission/downloads
TRANSMISSION_VOLUME_WATCH=/home/pi/volumes/transmission/watch
# ports
TRANSMISSION_EXTPORT_WEB=9091
TRANSMISSION_EXTPORT_TCP=51413
TRANSMISSION_EXTPORT_UDP=51413
PROXY_NETWORK=reverse_proxy_network

settings.json

{
    "alt-speed-down": 50,
    "alt-speed-enabled": false,
    "alt-speed-time-begin": 540,
    "alt-speed-time-day": 127,
    "alt-speed-time-enabled": false,
    "alt-speed-time-end": 1020,
    "alt-speed-up": 50,
    "bind-address-ipv4": "0.0.0.0",
    "bind-address-ipv6": "::",
    "blocklist-enabled": false,
    "blocklist-url": "http://www.example.com/blocklist",
    "cache-size-mb": 4,
    "dht-enabled": true,
    "download-dir": "/downloads/complete",
    "download-queue-enabled": true,
    "download-queue-size": 5,
    "encryption": 1,
    "idle-seeding-limit": 30,
    "idle-seeding-limit-enabled": false,
    "incomplete-dir": "/downloads/incomplete",
    "incomplete-dir-enabled": true,
    "lpd-enabled": false,
    "message-level": 2,
    "peer-congestion-algorithm": "",
    "peer-id-ttl-hours": 6,
    "peer-limit-global": 200,
    "peer-limit-per-torrent": 50,
    "peer-port": 51413,
    "peer-port-random-high": 65535,
    "peer-port-random-low": 49152,
    "peer-port-random-on-start": false,
    "peer-socket-tos": "default",
    "pex-enabled": true,
    "port-forwarding-enabled": true,
    "preallocation": 1,
    "prefetch-enabled": true,
    "queue-stalled-enabled": true,
    "queue-stalled-minutes": 30,
    "ratio-limit": 2,
    "ratio-limit-enabled": false,
    "rename-partial-files": true,
    "rpc-authentication-required": false,
    "rpc-bind-address": "0.0.0.0",
    "rpc-enabled": true,
    "rpc-host-whitelist": "",
    "rpc-host-whitelist-enabled": false,
    "rpc-password": "censored",
    "rpc-port": 9091,
    "rpc-url": "/transmission/",
    "rpc-username": "transmission",
    "rpc-whitelist": "",
    "rpc-whitelist-enabled": false,
    "scrape-paused-torrents-enabled": true,
    "script-torrent-done-enabled": false,
    "script-torrent-done-filename": "",
    "seed-queue-enabled": false,
    "seed-queue-size": 10,
    "speed-limit-down": 100,
    "speed-limit-down-enabled": false,
    "speed-limit-up": 100,
    "speed-limit-up-enabled": false,
    "start-added-torrents": true,
    "trash-original-torrent-files": false,
    "umask": 2,
    "upload-slots-per-torrent": 14,
    "utp-enabled": true,
    "watch-dir": "/watch",
    "watch-dir-enabled": true
}

[github-actions]

Thanks for opening your first issue here! Be sure to follow the bug or feature issue templates!

[j0nnymoe]

Could you provide everything else that was requested in the issue template please? This will help us work out what your issue is.

[doman18]

I updated the informations

[j0nnymoe]

Thanks, could you post your docker logs too?

[doman18]

I dont have direct access to machine at this moment. But i will when i get to my home.

Meanwhile i found that alpine problems are most probably connected with ibseccomp2. Here comment author claims that manual update with .deb file fixed his issues on rpi4.
gliderlabs/docker-alpine#386 (comment)

[j0nnymoe]

Yep that's what I'm expecting. Our docker logs should show a warning about that with a link on how to fix.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[rpgdev]

For the record the same happened to me. I was not able to access the webui even though the ports had been opened.