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What is LAN sync?

LAN sync is a Dropbox feature that speeds syncing dramatically when the file exists on your Local Area Network (LAN).

What does that mean exactly? Well, when you add a file to your computer's Dropbox, the file is then synced with Dropbox servers. Dropbox will then initiate the syncing process as soon as it determines a change has been made to the file. All linked computers and shared folders will then download any new version of the file. With LAN syncing, Dropbox will look for the new file on your Local Area Network first, bypassing the need to download the file from Dropbox servers, thus speeding up the syncing process considerably.

LAN sync is an extra advantage for use in locations where computers are networked together over the same router or other local area network.

For our advanced users

  • Dropbox needs to maintain a connection to the Internet in order to determine when to sync. To take advantage of LAN sync, all computers need to be connected to a LAN and the Internet at the same time.
  • If you are installing the Dropbox desktop application for the first time, Windows firewall might ask you for permission to allow Dropbox access to the internet and/or your LAN. Press Access to allow Dropbox to sync properly.
  • If Dropbox detects a firewall preventing access to your LAN, it will turn off LAN sync in your Dropbox preferences automatically. To turn it back on, change your Firewall settings to allow Dropbox access to the Internet and your LAN, then manually turn on LAN sync in your Dropbox preferences.
  • LAN sync only works with computers that are on the same subnet, or broadcast address. For example, usually all computers connected to a single router are on the same network (same subnet). If your LAN uses multiple network devices, such as routers, to extend its network, you will want to be on the same subnet as the other LAN sync-enabled computers. If this sounds foreign to you, you may want to consult your network device's documentation or a network administrator for help.
  • LAN Sync requires access to TCP port 17500.