Devcontainer setting remote.localPortHost=allInterfaces is not respected (2025)

[codeBehindMe]

Existing issue (closed) : #6445

• VSCode Version:
  Version: 1.102.3 (user setup)
  Commit: 488a1f239235055e34e673291fb8d8c810886f81
  Date: 2025-07-29T03:00:23.339Z
  Electron: 35.6.0
  ElectronBuildId: 11847422
  Chromium: 134.0.6998.205
  Node.js: 22.15.1
  V8: 13.4.114.21-electron.0
  OS: Windows_NT x64 10.0.26200

Insiders:
Version: 1.103.0-insider (user setup)
Commit: 34769c5d17df269aed44407eb1a1c0e6362e2d79
Date: 2025-08-04T21:43:35.566Z
Electron: 37.2.3
ElectronBuildId: 12035395
Chromium: 138.0.7204.100
Node.js: 22.17.0
V8: 13.8.500258-electron.0
OS: Windows_NT x64 10.0.26200

• Local OS Version: Windows 11 HOME 25H2
• Remote OS Version: Debian GNU/Linux 12 (bookworm)
• Remote Extension/Connection Type: Dev Containers/WSL/Remote - Dev Containers

Steps to Reproduce:

1. Open VSCode with the Remote - Containers extension installed.
2. Select Remote-Containers: Try a Development Container Sample from the command palette.
3. Choose Python
4. Wait for VSCode to switch, load, and build
5. Set Remote: Local Port Host setting to the allInterfaces option in all 3, workspace, user and remote settings. Reload window if necessary
6. Create a simple python fast api server

pip install fastapi[standard]

# main.py
from fastapi import FastAPI
import os

app = FastAPI()


@app.get("/")
async def root():
    return {"message": "Hello World"}

if __name__ == "__main__":
    app.run(debug=False, host="0.0.0.0", port=int(os.environ.get("PORT", 8080)))

uvicorn main:app --host 0.0.0.0

7. confirm that port is forwarded, incorrectly on localhost:8080
8. confirm access through browser on the host

9. confirm no access through curl command on host

Expected behaviour:

The forwarded port should be on 0.0.0.0:8080

Observed behaviour

The forwarded port is on localhost:8080

Does this issue occur when you try this locally?: N/A
Does this issue occur when you try this locally and all extensions are disabled?: N/A

[yp05327]

I also found this issue.
At first, it seems that this settings has changed, I can not access localhost:port any more in allinterface mode, but I can access ip:port, but it worked before. So I changed it to localhost at that time.
Now I want to use allinterface mode again, but it is not respected any more....