Open WebUI + Ollama issue on Ubunto

[squirrel-oss]

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Hi Folks, I am new to Github. Apologies if this is the wrong discussion for my problem.

Hoping someone can help with a stubborn Open WebUI + Ollama issue on Ubuntu.

I have Ollama running locally with llama3.1:8b working fine (ollama list confirms it). I’m running Open WebUI in Docker on the same server.

I’ve set up the connection pointing to http://host.docker.internal:11434/, Authentication = None, and limited it to the single model llama3.1:8b.

Every time I click Verify Connection or try to pull the model, I get “LAMA network problem”. The logs repeatedly show:
Cannot connect to host host.docker.internal:11434 ssl:default [Name or service not known]

I’ve tried:
Both the --add-host and --network=host versions of the docker run command
Deleting the connection completely and adding it fresh
Authority set to None
Single model mode instead of “all”

The container starts fine and I can reach the WebUI, but it just won’t talk to Ollama properly.
Would anyone have any ideas what I might be missing? I’d be really grateful for any suggestions.

Thanks in advance!

[Luke-Corwin]

The key part of the error is:

“Cannot connect to host host.docker.internal:11434 [Name or service not known]”

That suggests this isn’t actually an Ollama or model issue yet—it’s a networking/DNS resolution problem inside the Open WebUI container.

A couple things I’d check:

1. Open a shell inside the Open WebUI container and see if host.docker.internal resolves at all:

docker exec -it <container_name> bash
ping host.docker.internal

If it doesn’t resolve, Open WebUI will never be able to reach Ollama using that hostname.

2. From the Ubuntu host, verify Ollama is actually listening on an address other than localhost:

ss -tulpn | grep 11434

If Ollama is only bound to 127.0.0.1:11434, containers won’t be able to reach it even if DNS is working correctly.

3. Try accessing Ollama directly from inside the container using the host IP instead of host.docker.internal:

curl http://:11434/api/tags

If that works, you’ve narrowed the issue down to hostname resolution rather than Open WebUI itself.

One thing worth mentioning is that host.docker.internal works out of the box on Docker Desktop, but on Linux it can be a little more finicky depending on Docker version and how the container was started. In many Ubuntu setups I’ve had better luck using the host’s actual IP address or ensuring the host mapping is present inside the container.

I’d be curious whether curl http://host.docker.internal:11434/api/tags succeeds from inside the Open WebUI container. That would tell us very quickly whether the problem is DNS resolution, network reachability, or Ollama’s bind address.

[SwapnilSadhu007]

On Linux, host.docker.internal usually doesn’t resolve inside containers — it’s mainly supported on Docker Desktop for Windows/Mac. That’s why you’re seeing the “Name or service not known” error.

Try these fixes:

1. Use localhost:11434 or your host machine’s actual IP instead of host.docker.internal.
   Example: curl http://localhost:11434/api/tags from inside the Open WebUI container.

2. If that doesn’t work, run the container with --network=host so it shares the host’s network stack.

3. Alternatively, add a host mapping:
   docker run --add-host=host.docker.internal:host-gateway ...

These approaches should let Open WebUI connect properly to Ollama on Ubuntu.

[henderson-01]

Welcome to the community! Don't apologise. Docker networking on Linux is notoriously tricky and is a rite of passage for anyone getting into self-hosting.

The issue you are running into is caused by two overlapping quirks with how Linux, Docker, and Ollama handle networking:

1. Ollama's Default Security: By default, Ollama only listens to 127.0.0.1 (localhost). It actively ignores requests coming from outside the host machine, and to Ollama, a Docker container is considered "outside."
2. host.docker.internal on Linux: Unlike Docker Desktop for Mac/Windows, standard Docker Engine on Ubuntu doesn't automatically map host.docker.internal.

Even though you tried the --add-host flag, the connection was likely still refused because Ollama was shutting the door on the Docker bridge network.

Here is the step-by-step fix to get them talking.

Step 1: Tell Ollama to listen to the Docker network

We need to configure Ollama to bind to 0.0.0.0 (all network interfaces) so it can accept requests from your Docker container. Since you are on Ubuntu, Ollama is likely running as a systemd service.

1. Open your terminal and edit the Ollama systemd service:

sudo systemctl edit ollama.service

2. This will open a text editor (usually nano). Add the following lines exactly as written, ensuring the [Service] header is included:

[Service]
Environment="OLLAMA_HOST=0.0.0.0"

3. Save and exit (if using nano, press Ctrl+O, Enter, then Ctrl+X).
4. Reload systemd and restart Ollama to apply the changes:

sudo systemctl daemon-reload
sudo systemctl restart ollama

Step 2: Relaunch Open WebUI

Now that Ollama's door is open, we can run Open WebUI with the correct networking flag.

Run your Docker command using the --add-host flag to properly map host.docker.internal to the host machine's gateway:

docker run -d -p 3000:8080 --add-host=host.docker.internal:host-gateway -v open-webui:/app/backend/data --name open-webui --restart always ghcr.io/open-webui/open-webui:main

Step 3: Configure the WebUI Connection

1. Open your browser and navigate to your Open WebUI instance.
2. Go to Settings > Connections.
3. Set the Ollama Base URL to: http://host.docker.internal:11434
4. Click Verify Connection.

It should now flash green and connect successfully!

(Note: If you decided to use --network=host instead of --add-host in Step 2, your container shares the exact same network as your Ubuntu server. In that specific scenario, your connection URL inside Open WebUI should just be http://127.0.0.1:11434.)

Hope this helps

[shazeus]

No need to apologize at all—this is the perfect place to ask, and you ran into a very common Linux Docker quirk.
On Ubuntu, host.docker.internal does not resolve automatically out of the box like it does on Windows or macOS. The error [Name or service not known] means the Open WebUI container literally cannot find that address.
Here are the best ways to fix this, ordered from easiest to most reliable:

Fix 1: Use your Docker Bridge IP (Recommended)

Instead of relying on host.docker.internal, you can point Open WebUI directly to your Ubuntu host's gateway IP.

1. Find your gateway IP by running this in your Ubuntu terminal:

ip route show | grep default | awk '{print $3}'

(This usually outputs 172.17.0.1 or your local network IP).
2. In the Open WebUI settings, change the URL from http://docker.internal to http://YOUR_IP_HERE:11434.

Fix 2: Properly map the host gateway in Docker

If you want to keep using the host.docker.internal string, you have to explicitly tell Docker on Linux what it means using the host-gateway target.
Stop your current container and relaunch it ensuring this exact flag is included:

docker run -d -p 3000:8080 --add-host=host.docker.internal:host-gateway --name open-webui --restart always ghcr.io/open-webui/open-webui:main

Fix 3: Check Ollama's Bind Address (OLLAMA_HOST)

By default, Ollama on Linux often binds strictly to 127.0.0.1 (localhost). If it does, Docker containers cannot talk to it.

1. Check what address Ollama is listening on:

sudo ss -tulpn | grep 11434

2. If it shows 127.0.0.1:11434, it is blocking outside traffic. Change it to 0.0.0.0 by editing the systemd service:

sudo systemctl edit ollama.service

3. Add these lines, save, and exit:

[Service]
Environment="OLLAMA_HOST=0.0.0.0"

4. Reload and restart the service:

sudo systemctl daemon-reload
sudo systemctl restart ollama

Give Fix 1 or Fix 2 a shot first, as they usually clear up the DNS routing issue immediately. Let us know if that gets it working for you!

[Gecko51]

The other replies have the core fix covered. One extra option worth knowing about if you want to avoid managing long docker run commands: Docker Compose handles the host mapping cleanly with extra_hosts.

A minimal compose file that works on Ubuntu:

services:
  open-webui:
    image: ghcr.io/open-webui/open-webui:main
    ports:
      - "3000:8080"
    extra_hosts:
      - "host.docker.internal:host-gateway"
    volumes:
      - open-webui:/app/backend/data
    restart: always

volumes:
  open-webui:

The extra_hosts entry is the same as --add-host=host.docker.internal:host-gateway but it persists across restarts without you having to remember the flag each time.

You still need the OLLAMA_HOST=0.0.0.0 change in the systemd service (as others mentioned above), so Ollama stops binding exclusively to localhost. Once you've restarted the service after that change, Open WebUI should connect cleanly at http://host.docker.internal:11434.

[v-ember]

Hi @squirrel-oss , thanks for posting in GitHub Discussions!

The Pull Request category is meant for questions related to conversations related to GitHub Pull Requests. Use pull requests to suggest changes to a project, receive suggested changes to your own projects. I've gone ahead and moved this post to our Programming Help category, as this topic may be more relevant there and might help someone give you a nudge in the right direction. 😁