Introducer concept in Syncthing

The “Introducer” concept in Syncthing is a useful feature designed to streamline the process of connecting multiple devices in a network. Here’s how it works and why it can be beneficial:

What is an Introducer in Syncthing?

An Introducer is a device that, once trusted by other devices, can introduce these devices to each other, facilitating their connection without the need for manual intervention. Essentially, it acts as a central point that simplifies the process of adding new devices to your Syncthing network.

How the Introducer Concept Works

  1. Initial Setup:

    • You set up Syncthing on multiple devices (let’s call them Device A, Device B, and Device C).
    • You connect Device A with Device B manually and also connect Device A with Device C manually.

  2. Marking Device A as an Introducer:

    • On Device B and Device C, you mark Device A as an “Introducer”.
    • This tells Device B and Device C to automatically trust and connect to any other devices that Device A introduces.

  3. Automatic Introduction:

    • When Device A is connected to a new device (let’s say Device D), Device A will inform Device B and Device C about Device D.
    • Device B and Device C will then automatically connect to Device D, assuming they are set to accept introductions.

Benefits of Using an Introducer

  • Reduced Manual Effort: You don’t need to manually connect every new device to all other devices. Simply connect the new device to the Introducer, and it will handle the rest.
  • Scalability: In larger setups, managing connections manually can be tedious and error-prone. The Introducer feature makes it easier to scale the network by automating connections.
  • Consistency: Ensures that all devices in your network are aware of each other, maintaining a consistent and fully connected network without missing any nodes.

Example Scenario

Imagine you have a network of 10 devices that need to sync files with each other. Without an Introducer, you would need to manually add each new device to all other 9 devices. With an Introducer:

  • You connect the new device to the Introducer.
  • The Introducer will inform all other devices about this new device.
  • All devices will automatically establish connections with the new device, ensuring they are all in sync.

How to Set Up an Introducer

  1. Connect Devices: First, manually connect the devices you want to act as Introducers to other devices.
  2. Mark as Introducer: In the device settings (under the Remote Devices section) of the devices you want to be Introduced, enable the Introducer option for the device acting as the Introducer.
  3. Automatic Updates: The Introducer will now automatically introduce new devices to the ones that have trusted it.

Considerations

  • Trust: Only mark trusted devices as Introducers to avoid unwanted devices being introduced to your network.
  • Network Size: In very large networks, consider how introductions will affect network traffic and device performance.

By understanding and utilizing the Introducer feature in Syncthing, you can significantly simplify the management of your device network, making it easier to add new devices and ensuring all devices stay connected seamlessly.