AdguardTeam/AdGuardHome

Docker Containers can connect to AdGuard GUI but Unable to Resolve via host IP

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#6,442 opened on Nov 19, 2023

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Description

Prerequisites

Platform (OS and CPU architecture)

Linux, AMD64 (aka x86_64)

Installation

Docker

Setup

On one machine

AdGuard Home version

v0.107.41

Action

Please bear with me on this. It's a confusing issue.

First of all, adguard docker-compose.yml:

version: "3.9"
services:
  adguardhome:
    image: adguard/adguardhome
    container_name: adguardhome
    ports:
      - 53:53/tcp
      - 53:53/udp
      - 3000:3000/tcp
      - 3001:80/tcp
      - 3002:8902/tcp
    volumes:
      - ./conf:/opt/adguardhome/conf
      - ./data:/opt/adguardhome/work
    restart: always
    network_mode: bridge

Pretty vanilla setup.

The host IP here is 192.168.25.81.

user@192.168.25.81$ nslookup google.com 192.168.25.81
<success>

# now try to resolve from another docker container:
user@192.168.25.81:~/docker-configs/mosquitto$ docker compose exec mosquitto nslookup google.com 192.168.25.81
;; connection timed out; no servers could be reached

# however, the adguard container can still be reached on different ports.. why is that??
user@192.168.25.81:~/docker-configs/mosquitto$ docker compose exec mosquitto wget 192.168.25.81:3001 -O -
Connecting to 192.168.25.81:3001 (192.168.25.81:3001)
writing to stdout
<!doctype html><html lang="en"><head><meta charset="utf-8"><me.... (snip)

### Expected result

I should be able to use the host IP to resolve from other containers. Since it can connect to the GUI, why can't it connect to the DNS server on port 53?

### Actual result

See above. Thank you!

### Additional information and/or screenshots

_No response_

Contributor guide

Tech stack
godocker
Domain
backendinfrastructure
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Docker networking conceptsDNS resolution basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45
Research direction
Investigate whether AdGuard Home's DNS listener is binding to the Docker bridge network interface. Check the AdGuard Home configuration file (AdGuardHome.yaml) for the 'bind host' setting. Also verify that the host firewall is not blocking port 53 for Docker containers. Consider testing with network mode: host to see if it resolves. See related discussions in the GitHub issue comments.