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