QNAP – Multiple outgoing connection on UDP port 6881

A few weeks ago, while analyzing a customer’s network, I’ve discovered that their QNAP NAS was making a lot of outgoing connections on UDP port 6881.

Knowing that this NAS is only used as an internal repository for Veeam backup, I knew that this traffic was not wanted.

Here is an example of the traffic :

After a quick search, it appears that this port is a BitTorrent port. This search confirms that this is an unwanted network traffic.

So, I’ve looked up on the QNAP documentation and forum, and I’ve discovered a post that was speaking about this problem.

This problem is linked to the package “Download Station” that is installed on this QNAP.

Here is the way to solve the problem :

  • Open the Download Station
  • Go to the Settings and then “BT”
  • On the “BT” tabs, select the “Connection” and then uncheck the two boxes “Enable DHT network” and “Enable UPnP port mapping
  • After a few seconds, all the connections will be terminated

 

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