Unable to access agents via Caddy reverse proxy.

[RevenantOne]

🔍 Check for existing issues

• Completed

How is Dozzle deployed?

Agents

📦 Dozzle version

v8.14.10

✅ Command used to run Dozzle

docker compose up -d

Host docker-compose.yml:

services:
  dozzle:
    container_name: dozzle
    image: amir20/dozzle:latest
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - /opt/Docker/Dozzle/data:/data
    restart: unless-stopped
    environment:
      - PUID=1001
      - PGID=1001
      - TZ=Europe/London
      - DOZZLE_NO_ANALYTICS=true
      - DOZZLE_AUTH_PROVIDER=simple
      - DOZZLE_HOSTNAME=DozzleHost
      - DOZZLE_ENABLE_ACTIONS=true
      - DOZZLE_REMOTE_AGENT=dozzle.domain.tld
    ports:
      - 3023:8080
    deploy:
      resources:
        limits:
          memory: 2G
        reservations:
          memory: 1G

Agent docker-compose.yml:

services:
  dozzle:
    container_name: dozzle
    image: amir20/dozzle:latest
    command: agent
    healthcheck:
      test: ["CMD", "/dozzle", "healthcheck"]
      interval: 5s
      retries: 5
      start_period: 5s
      start_interval: 5s
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
    ports:
      - 7007:7007

Caddyfile:

dozzle.domain.tld {
        reverse_proxy 127.0.0.1:7007

         log {
                output file /var/log/caddy/dozzle.log {
                }
}

🐛 Describe the bug / provide steps to reproduce it

I've set up Dozzle on two seperate networks, one as host and one as an agent. I've followed the agent guide to no avail.

They both work fine as stand alone instances, but if I attempt to set one as an agent and use caddy (v2.6.2) as a reverse proxy it fails. I've tried to troubleshoot with ChatGPT and it suggests it's due to caddy sending a html page rather than the expected JSON. I've searched on line and tried the caddyfile config located here and more than a dozen suggestions from ChatGPT, as well as the flush_interval -1 that's been suggested here.

I can confirm it works if I bypass Caddy and use http://IP-ADDRESS:PORT as the DOZZLE_REMOTE_AGENT value , but I'd rather not go that way for security reasons.

Am I missing a config for Dozzle or is this purely down to Caddy misbehaving?

💻 Environment

Host Environment:

Client:
 Version:    28.2.2
 Context:    default
 Debug Mode: false
 Plugins:
  compose: Docker Compose (Docker Inc.)
    Version:  2.37.1+ds1-0ubuntu2~24.04.1
    Path:     /usr/libexec/docker/cli-plugins/docker-compose

Server:
 Containers: 40
  Running: 32
  Paused: 0
  Stopped: 8
 Images: 65
 Server Version: 28.2.2
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: systemd
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
 CDI spec directories:
  /etc/cdi
  /var/run/cdi
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version:
 runc version:
 init version:
 Security Options:
  apparmor
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.8.0-88-generic
 Operating System: Ubuntu 24.04.3 LTS
 OSType: linux
 Architecture: x86_64
 CPUs: 12
 Total Memory: 62.69GiB
 Name:  **REDACTED**
 ID: df2e2716-7e2b-4918-9244-08a2f7119559
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Experimental: false
 Insecure Registries:
  ::1/128
  127.0.0.0/8
 Live Restore Enabled: false

Agent Environment:

Client:
 Version:    27.5.1
 Context:    default
 Debug Mode: false
 Plugins:
  compose: Docker Compose (Docker Inc.)
    Version:  2.37.1+ds1-0ubuntu2~24.04.1
    Path:     /usr/libexec/docker/cli-plugins/docker-compose

Server:
 Containers: 41
  Running: 40
  Paused: 0
  Stopped: 1
 Images: 42
 Server Version: 27.5.1
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: systemd
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version:
 runc version:
 init version:
 Security Options:
  apparmor
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.14.0-36-generic
 Operating System: Ubuntu 24.04.3 LTS
 OSType: linux
 Architecture: x86_64
 CPUs: 12
 Total Memory: 15.54GiB
 Name: **REDACTED**
 ID: ed87f4d7-9b02-45d2-9fb1-c09e2e44c651
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Username: **REDACTED**
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

📜 Dozzle logs are required for debugging purposes. You may need to enable debug mode. See https://dozzle.dev/guide/debugging.

Host Logs:

{"level":"warn","version":"v8.14.10","error":"rpc error: code = PermissionDenied desc = unexpected HTTP status code received from server: 403 (Forbidden); transport: received unexpected content-type \"text/html\"","endpoint":"dozzle.domain.tld","time":"2025-12-09T23:50:53Z","message":"error fetching host info for agent"}
{"level":"warn","version":"v8.14.10","error":"rpc error: code = PermissionDenied desc = unexpected HTTP status code received from server: 403 (Forbidden); transport: received unexpected content-type \"text/html\"","time":"2025-12-09T23:50:53Z","message":"error while listing containers"}

📸 If applicable, add screenshots to help explain your bug

No response

[amir20]

This is not a bug so moving to discussion.