When using through Docker container, can't connect from another machine using IP

[MekayelAnik]

Describe the bug
When using through the Docker container, can't connect from another machine using IP

To Reproduce
Steps to reproduce the behavior:

1. Deploy the inspector using this Docker compose file:

services:
  mcp-inspector:
    image: ghcr.io/modelcontextprotocol/inspector:latest
    container_name: mcp-inspector
    ports:
      - "6274:6274"
      - "6277:6277"
    environment:
      - CLIENT_PORT=6274
      - SERVER_PORT=6277
      - MCP_PROXY_FULL_ADDRESS=http://10.7.7.211:6274
      - MCP_AUTO_OPEN_ENABLED=false
      - DANGEROUSLY_OMIT_AUTH=true
    hostname: mcp-inspector
    domainname: local
    restart: unless-stopped
    network_mode: host

2. Try to acces the Inspector from browser using : http://10.7.7.211:6274 (FAILED)
3. Curl: curl http://10.7.7.211:6274 RESULT: curl: (7) Failed to connect to 10.7.7.211 port 6274 after 0 ms: Could not connect to server
4. Curl: curl http://localhost:6274 RESULT: returns html.

NOTE: The docker host is headless

Expected behavior
The WebUI should be accessible from any machine on local network

Logs

> @modelcontextprotocol/inspector@0.16.6 start

> node client/bin/start.js

Starting MCP inspector...

⚙️ Proxy server listening on localhost:6277

⚠️  WARNING: Authentication is disabled. This is not recommended.

🚀 MCP Inspector is up and running at:

   http://localhost:6274

Please help me if I need to change anything to make it work.

[FournyP]

Hi everyone,

I face the same issue locally. Even using the command in the README, with all of that versions :

• 0.16.6
• 0.16.5
• 0.16.4
• 0.16.3
• 0.16.2
• 0.16.1
• 0.16.0
• 0.15.0
• 0.14.3

I didn't tested earlier versions as I face always the same result

Here my local setup :

• macOS 15.6.1
• Docker version 28.3.3, build 980b856

The docker-compose I use :

services:
  mcp-inspector:
    image: ghcr.io/modelcontextprotocol/inspector:latest
    container_name: mcp-inspector
    ports:
      - "6274:6274"
      - "6277:6277"
    environment:
      - CLIENT_PORT=6274
      - SERVER_PORT=6277
      - MCP_AUTO_OPEN_ENABLED=false
      - DANGEROUSLY_OMIT_AUTH=true
    domainname: local

The logs of the container :

> @modelcontextprotocol/inspector@0.16.6 start
> node client/bin/start.js

Starting MCP inspector...
⚙️ Proxy server listening on localhost:6277
⚠️  WARNING: Authentication is disabled. This is not recommended.

🚀 MCP Inspector is up and running at:
   [http://localhost:6274⁠](http://localhost:6274/)

[Jokimbe]

Adding

environment: 
    - HOST=0.0.0.0

to your docker-compose.yml will fix this, documentation on this could be clearer tho ;)

EDIT:
Oh and also this line needs to be added to environment:
- ALLOWED_ORIGINS=http://<HOST-IP>:6274,http://<HOST-IP>:8000

[cliffhall]

You can also try the published docker container:

docker run --rm --network host -p 6274:6274 -p 6277:6277 ghcr.io/modelcontextprotocol/inspector:latest

[MekayelAnik]

Adding

environment: 
    - HOST=0.0.0.0

to your docker-compose.yml will fix this, documentation on this could be clearer tho ;)

EDIT:
Oh and also this line needs to be added to environment:
- ALLOWED_ORIGINS=http://<HOST-IP>:6274,http://<HOST-IP>:8000

This worked. Thanks! 👍

[xmontero]

I needed to do this in order to do not receive a "Recv failure: Connection reset by peer":

docker run --rm -it --name mcp -e MCP_AUTO_OPEN_ENABLED=false -p 6274:6274 -p 6277:6277 -e HOST=0.0.0.0 ghcr.io/modelcontextprotocol/inspector:latest

Context: Running Windows, inside Windows, running WSL. Inside a Docker Desktop linked to WSL. Inside this docker, running the image. Nevertheless, the browser working on Windows and accessing http://localhost:6274/?MCP_PROXY_AUTH_TOKEN=xxxxxxxxxx