this post was submitted on 05 Apr 2026
14 points (85.0% liked)

Selfhosted

58238 readers
840 users here now

A place to share alternatives to popular online services that can be self-hosted without giving up privacy or locking you into a service you don't control.

Rules:

  1. Be civil: we're here to support and learn from one another. Insults won't be tolerated. Flame wars are frowned upon.

  2. No spam posting.

  3. Posts have to be centered around self-hosting. There are other communities for discussing hardware or home computing. If it's not obvious why your post topic revolves around selfhosting, please include details to make it clear.

  4. Don't duplicate the full text of your blog or github here. Just post the link for folks to click.

  5. Submission headline should match the article title (don’t cherry-pick information from the title to fit your agenda).

  6. No trolling.

  7. No low-effort posts. This is subjective and will largely be determined by the community member reports.

Resources:

Any issues on the community? Report it using the report flag.

Questions? DM the mods!

founded 2 years ago
MODERATORS
ruud@lemmy.world
Loki@lemmy.world
CannaVet@lemmy.world
devve@lemmy.world
HybridSarcasm@lemmy.world
HybridSarcasm@lemmy.hybridsarcasm.xyz
14
Docker networking help (vlans) (programming.dev)
submitted 19 hours ago* (last edited 19 hours ago) by zo0@programming.dev to c/selfhosted@lemmy.world
10 comments fedilink hide all child comments
 

Hi folks, hope your weekend is going well.

So I have put myself into a situation. I have a home server with docker installed running fine so far. In my home network I have multiple networks for different purposes. The whole network stack looks like this OPNSense

Switch

Ubuntu Server

The server is connected to a switch port with pvid 100, and runs on vlan0.100 Now my goal is to move some docker containers to other vlans. To accomplish that I have set vlan0.101 and vlan0.102 on my server as interfaces with their own IP and default gateway on that subnet (e.g. 192.168.101.10) Next step I set up macvlans for my docker containers Then I set the port to also allow tagged traffic, but kept it on pvid 100. Now on my OPNSense I changed the host ip of my server from 192.168.100.10 to include all 3 IPs so homeserver 192.168.100.10, 192.168.101.10, 192.168.102.10

This setup seems to work fine for internal network, however no services are reachable from the outside (internet) anymore.

My first question is: Am I thinking correctly about this? Or is this over-engineered bs at this point and there is a better way to put docker containers on different subnets.

Second question is: Any ideas what's breaking the internet access?

Thanks for the help in advance :D

EDIT: i have not changed the vlan of any container yet

you are viewing a single comment's thread
view the rest of the comments
[–] zo0@programming.dev 1 points 17 hours ago (2 children)

Answer to your first question, he dockers successfully resolve and access internet

  1. Yes the OPNSense is the primary router and dhcp provider so all the subnets and vlans are defined and working with physical devices

I actually was having the same issue with the routing of server. How did you setup your bridge exactly? Do you mind sharing your netplan?

[–] probable_possum@leminal.space 1 points 13 hours ago* (last edited 12 hours ago)

Netplan config? Sure:

network:
  ethernets:
    enp35s0:
      dhcp4: false
    enp36s0:
      dhcp4: false
  vlans:
    enp35s0.100:
      id: 100
      link: enp35s0
      dhcp4: false
    enp35s0.101:
      id: 101
      link: enp35s0
      dhcp4: false
  bridges:
     br0:
	   # untagged
       interfaces: [enp35s0]
       dhcp4: false
     br0.100:
	   # vlan 100
       interfaces: [enp35s0.100]
       dhcp4: false
     br0.101:
	   #vlan 101
       interfaces: [enp35s0.101]
       dhcp4: true
  version: 2

I'm not sure if the version-property is still required. The only interface with an IP is br0.101. Opnsense provides DHCP (v4).

You can attach multiple ethernet-devices to a bridge (which I did not):

      br0.100:
        interfaces:
          - enp35s0.100
          - two
	        - three

I'm not sure if you can attach the docker bridge via netplan - it has to exist at boot time, I think. My docker containers run inside a VM (kvm) with one interface, which sits in one of the VLANs. The VM's interface is a bridge device (br0.100). The VM ethernet device is attached to the bridge, it receives its IP from the router and behaves like a real server.

[–] surewhynotlem@lemmy.world 1 points 16 hours ago (1 children)

Bridge? There's your problem I think. Bridge doesn't allow ingress to individual IPs. In bridge, you tell each container what port it listens on, then access it from the IP of the host.

User defined bridges act differently from the default one as well. May not be relevant to your issue, but https://docs.docker.com/engine/network/drivers/bridge/#differences-between-user-defined-bridges-and-the-default-bridge

[–] zo0@programming.dev 1 points 15 hours ago (1 children)

I mean at the moment I don't have any bridges setup (other than the dockers own bridge) I thought maybe I could solve my issue with bridging

[–] surewhynotlem@lemmy.world 1 points 12 hours ago

Oh, hmm. How are you telling which service to be on which IP then? Could you safely post your compose file?