Setting up a headless file server with Ubuntu Server and Syncthing is a great way to manage your files within your home network. Ensuring everything is configured correctly, especially the firewall, is crucial for smooth operation. This guide addresses a common issue where users find they cannot access the Syncthing Graphical User Interface (GUI) in their browser after installation on Ubuntu Server.
A frequent problem arises when the Ubuntu Server’s firewall, UFW (Uncomplicated Firewall), is active. By default, UFW might block the ports Syncthing uses for its web interface, leading to a “Timed Out” error in your browser, preventing you from reaching the Syncthing GUI. Let’s explore how to resolve this and properly configure your firewall for LAN-only Syncthing access.
One of the first steps when configuring Syncthing for a local network is to ensure it’s correctly bound to your LAN interface. Within Syncthing’s config.xml file, you’ll find options to specify the listening address. For a home LAN setup, you’ll want to ensure Syncthing is set to listen on the appropriate network interface, often represented by 0.0.0.0 to listen on all interfaces, or more specifically to your server’s LAN IP address. Here’s a visual representation of configuration choices you might encounter:
However, even with the correct Syncthing configuration, the firewall can still be the culprit preventing GUI access. The user in the original post correctly identified that disabling UFW (sudo ufw disable) resolved the “Timed Out” error, confirming the firewall is indeed blocking access. Simply allowing ports 22000 and 80, as suggested by some online resources, may not be sufficient.
To properly allow access to the Syncthing GUI, you need to ensure that UFW is configured to permit traffic on the ports Syncthing uses for its web interface and communication. While port 22000 is commonly used by Syncthing for device-to-device communication, the GUI typically runs on port 8384. Port 80 is for HTTP, and while sometimes used in configurations, port 443 (HTTPS) or a dedicated GUI port like 8384 is more common for Syncthing’s web interface.
Therefore, to fix the “Timed Out” error and access your Syncthing GUI on Ubuntu Server, you should open the correct port in your UFW firewall. Use the following commands to allow traffic on port 8384 (the default GUI port) and port 22000 (Syncthing’s default communication port):
sudo ufw allow 8384/tcp
sudo ufw allow 22000/tcpAfter running these commands, ensure UFW is enabled (sudo ufw enable) and then try accessing the Syncthing GUI in your browser again, typically at http://<your_server_ip>:8384. This configuration should allow you to access the Syncthing GUI while keeping your Ubuntu server protected by the UFW firewall. Remember to replace <your_server_ip> with the actual IP address of your Ubuntu server on your local network.
