Dropbox LanSync Protocol

DB-LSP (Dropbox LAN Sync Protocol) is used by Dropbox clients to synchronize files over a local network. This service helps in speeding up the file transfer process by avoiding the need to upload and download files from the cloud. It is particularly useful in environments with multiple Dropbox users on the same network.

What is Dropbox LanSync Protocol

DB-LSP, or Dropbox LAN Sync Protocol, is a service used by Dropbox to facilitate faster file synchronization between clients on the same local network. By leveraging the local network, Dropbox can bypass the need to upload files to the cloud and then download them to other devices, significantly speeding up the synchronization process.

This protocol is especially beneficial in office environments or homes where multiple users share the same network and frequently collaborate on files. Instead of each user downloading the same file from the internet, DB-LSP allows the file to be transferred directly from one device to another, reducing bandwidth usage and improving efficiency.

Dropbox, a well-known file hosting service, introduced this feature to enhance user experience by providing quicker access to shared files. The service operates on port 17500 and is automatically enabled in Dropbox clients. However, it requires that all devices involved in the sync are on the same local network and have LAN Sync enabled in their Dropbox settings.

Dropbox LanSync Protocol runs on TCP port 17500 and is official IANA port.

Security risk

If port 17500 is open and the DB-LSP service is running, it could potentially expose the local network to unauthorized access. An attacker could exploit this open port to intercept or manipulate file transfers. It is crucial to ensure that proper network security measures, such as firewalls and encryption, are in place to mitigate these risks.

In our UFW tutorial you can follow instructions how you can configure UFW to close port 17500. Use StackChanges to monitor if the Dropbox LanSync Protocol port is closed and stays closed. StackChanges will send an alert if port 17500 is open again.