Cannot open TUN/TAP dev /dev/net/tun: No such device (errno=19)

[T0MuX]

Is there a pinned issue for this?

• I have read the pinned issues and could not find my issue

Is there an existing or similar issue/discussion for this?

• I have searched the existing issues
• I have searched the existing discussions

Is there any comment in the documentation for this?

• I have read the documentation, especially the FAQ and Troubleshooting parts

Is this related to a provider?

• I have checked the provider repo for issues
• My issue is NOT related to a provider

Are you using the latest release?

• I am using the latest release

Have you tried using the dev branch latest?

• I have tried using dev branch

Docker run config used

I can't gather the docker command. All I see is dumb-init /etc/openvpn/start.sh, and the environment variables which I list below :

            "Env": [
                "TRANSMISSION_RPC_ENABLED=true",
                "TRANSMISSION_RPC_AUTHENTICATION_REQUIRED=true",
                "OPENVPN_CONFIG=seedbox",
                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                "OPENVPN_USERNAME=",
                "OPENVPN_PASSWORD=",
                "OPENVPN_PROVIDER=custom",
                "OPENVPN_OPTS=",
                "GLOBAL_APPLY_PERMISSIONS=true",
                "TRANSMISSION_HOME=/config/transmission-home",
                "TRANSMISSION_RPC_PORT=9091",
                "TRANSMISSION_RPC_USERNAME=t0mux",
                "TRANSMISSION_RPC_PASSWORD=********************",
                "TRANSMISSION_DOWNLOAD_DIR=/mnt/SEED",
                "TRANSMISSION_INCOMPLETE_DIR=/data/incomplete",
                "TRANSMISSION_WATCH_DIR=/data/watch",
                "CREATE_TUN_DEVICE=true",
                "ENABLE_UFW=false",
                "UFW_ALLOW_GW_NET=false",
                "UFW_EXTRA_PORTS=",
                "UFW_DISABLE_IPTABLES_REJECT=false",
                "PUID=",
                "PGID=",
                "PEER_DNS=true",
                "PEER_DNS_PIN_ROUTES=true",
                "DROP_DEFAULT_ROUTE=",
                "WEBPROXY_ENABLED=false",
                "WEBPROXY_PORT=8118",
                "WEBPROXY_USERNAME=",
                "WEBPROXY_PASSWORD=",
                "LOG_TO_STDOUT=false",
                "HEALTH_CHECK_HOST=google.com",
                "SELFHEAL=false",
                "REVISION=07f5a2b9aea5028c9bb75438c1552708e91dde71"
            ],

Current Behavior

The container starts, and then fail at the TUN/TAP opening step

Expected Behavior

I just expect this works normaly :) I mean, this was the case just before this happens (and I actually don't know why). It worked very well just before.

How have you tried to solve the problem?

I tried to force stop the container, and start again.
Tried to stop de Docker package on DSM, and restart.
Checked updates, DSM and packages are all up to date.
Restarted my entire NAS, no change.

Log output

HW/SW Environment

- NAS : Synology DS712+
- OS: DSM 6.2.4
- Docker: 20.10.3

Anything else?

No response

[ryant00000]

I also had this issue, and found that passing through a /dev/net/tun device and setting CREATE_TUN_DEVICE=false at least works around the problem. My setup worked for years at this point, I suspect some docker change is relevant but couldn't find it. Notably, setting cap_add to ALL did not solve the problem.

[sadsephiroth]

I also had this issue today, setting container to Privileged mode worked, but is not an actual solution.

[boxedbiscotti]

Also having the same issue, version 5.3.1, using NordVPN if providers matter in this instance is currently unclear.

[hypevhs]

I'm also affected by this, but my error message is slightly different. I was unable to determine which of the many changes that --privileged applies is what allows access to the /dev/net/tun that the start script creates.

[T0MuX]

I also had this issue, and found that passing through a /dev/net/tun device and setting CREATE_TUN_DEVICE=false at least works around the problem. My setup worked for years at this point, I suspect some docker change is relevant but couldn't find it. Notably, setting cap_add to ALL did not solve the problem.

I tried, but no success :

[T0MuX]

I also had this issue today, setting container to Privileged mode worked, but is not an actual solution.

Mine is already on Priviliged mode :/

[sagefarrenholz]

Seeing the same with NORDVPN

[sagefarrenholz]

I was able to fix by adding

  privileged: true

to my container config in my compose file

[niemtec]

Started happening to me too after pulling latest image.

[realdeeguy]

Same issue. I don't want to run the container in privileged mode, so I manually added the TUN device by including the following in the compose file. Hope this helps.

devices:
  - /dev/net/tun:/dev/net/tun

[T0MuX]

Same issue. I don't want to run the container in privileged mode, so I manually added the TUN device by including the following in the compose file. Hope this helps.

devices:
  - /dev/net/tun:/dev/net/tun

How can I do that on DSM 6.2.4 ? I looked for it, didn't found anything :(

[thewanka]

When I include the following in my docker-compose file:

devices:  
  - /dev/net/tun:/dev/net/tun  

I get the error:

ERROR: Cannot open TUN/TAP dev /dev/net/tun: Operation not permitted (errno=1)

However, if I set privileged: true, the error disappears.

I would prefer to resolve the issue without granting Docker privileged access. If anyone has suggestions, I’d greatly appreciate your help.

[realdeeguy]

When I include the following in my docker-compose file:

devices:  
  - /dev/net/tun:/dev/net/tun  

I get the error:

ERROR: Cannot open TUN/TAP dev /dev/net/tun: Operation not permitted (errno=1)

However, if I set privileged: true, the error disappears.

I would prefer to resolve the issue without granting Docker privileged access. If anyone has suggestions, I’d greatly appreciate your help.

Share your compose file, this should work

[AdamLMark]

devices:
  - /dev/net/tun:/dev/net/tun

Thank you, this worked for me. Here's my entire compose Portainer stack for anyone interested:

version: "3.3"
services:
  transmission-openvpn:
    container_name: transmission-openvpn
    cap_add:
      - NET_ADMIN
    volumes:
      - /docker/transmission-openvpn/config:/config
      - /mnt/data/torrents:/data/torrents
    logging:
      driver: json-file
      options:
        max-size: 10m
    ports:
      - '9091:9091'
    devices:
      - /dev/net/tun:/dev/net/tun
    image: haugene/transmission-openvpn
    env_file:
      - stack.env # Lets you use Portainer's environment variables (file doesn't need to exist)
    restart: unless-stopped

[thewanka]

When I include the following in my docker-compose file:

devices:  
  - /dev/net/tun:/dev/net/tun  

I get the error:
ERROR: Cannot open TUN/TAP dev /dev/net/tun: Operation not permitted (errno=1)
However, if I set privileged: true, the error disappears.
I would prefer to resolve the issue without granting Docker privileged access. If anyone has suggestions, I’d greatly appreciate your help.

Share your compose file, this should work

I made a mistake and when I corrected my compose it worked. Thanks

devices:
  - /dev/net/tun:/dev/net/tun