10: Syncthing - File Synchronization

Syncthing provides continuous, peer‑to‑peer file synchronization across devices. For configuration reference and advanced topics (relays, discovery, ignore patterns), see the official Syncthing documentation.

Dependency check

• Required: Docker (Chapter 3)
• Optional: Traefik (Chapter 4) + subdomain (Chapter 4.5) for HTTPS/UI exposure
• Optional: Borgmatic (Chapter 6) for file data protection

Prerequisites

• ✅ Docker running (Chapter 3)
• ✅ Optional: Traefik installed (Chapter 4) + subdomain (Chapter 4.5), e.g., sync.example.com
• ✅ Optional: Borgmatic installed (Chapter 6) for backups

Installation via Infinity Tools

Menu Installation

📱 APPLICATIONS → Syncthing → Install

CLI Installation

sudo bash /opt/InfinityTools/Solutions/setup-syncthing.sh --install

Traefik Integration

Select Traefik mode to expose the web UI via HTTPS and a domain:

labels:
  - "traefik.enable=true"
  - "traefik.http.routers.syncthing.rule=Host(`sync.example.com`)"
  - "traefik.http.routers.syncthing.entrypoints=websecure"
  - "traefik.http.routers.syncthing.tls.certresolver=myresolver"
  - "traefik.http.services.syncthing.loadbalancer.server.port=8384"  # Syncthing GUI

networks:
  - proxy

Standalone Access

Without Traefik, map the GUI port directly and use self‑signed HTTPS:

ports:
  - "8384:8384"   # Web GUI (HTTPS)
  # Syncthing protocol ports are internal to the container; peers connect via relay/UPnP/NAT traversal

Data & Configuration

volumes:
  - /opt/speedbits/syncthing/config:/var/syncthing
  - /opt/speedbits/syncthing/Documents:/sync/Documents
  - /opt/speedbits/syncthing/Photos:/sync/Photos

Security & Hardening

• Set GUI credentials (Settings → GUI)
• Restrict GUI to 0.0.0.0 only when behind Traefik; otherwise bind locally and reverse‑proxy
• Consider IP allowlists via Traefik middleware for WAN exposure

Device Pairing

1. Retrieve Device ID from each peer (web UI → Actions → Show ID)
2. Add remote devices by ID; accept on the peer
3. Share specific folders with your peer device

Ignore Patterns

Use .stignore to exclude files:

# /opt/speedbits/syncthing/Documents/.stignore
*.tmp
.cache/
node_modules/

Operational Checks

# Containers
sudo docker ps | grep syncthing

# Logs
sudo docker logs syncthing --since 10m

Troubleshooting

• Ensure DNS resolves sync.example.com if using Traefik
• Confirm the GUI is reachable via Traefik or mapped port
• Validate folder permissions (UID/GID 1000 by default in LinuxServer images)

For advanced networking (relay servers, global discovery, NAT traversal), consult the Syncthing docs.