I frequently use tcptrack to track ongoing TCP connections on my server. One thing I have observed is that it shows negative speed for TCP/IPv6 connections with low bandwidth consumption for example a less active SSH session. Following is an example image from my server.
There are two ongoing ssh connections to the server; both are over IPv6. The second SSH connection shown in the picture is active and the upper one is idle. You can see the upper one is showing a speed of -1068 B/s and the total speed shown at the button of the picture is also a negative number (-1008 B/s)
I never observed a negative connection speed for IPv4 with tcptrack. Can anyone please help me in understanding this?
Note: This observation is not specific for a particular variant of Linux or any particular version of the tcptrack. This happens always on all platforms of linux and all versions of tcptrack I have ever used.
