Connection Chart

The connection chart can be used to visualize connection-related information, such as the number of active established connections, handshake attempts, successful TLS Session Resumptions or failed handshakes.

$ tools/ -k active -- DoT.json
$ tools/ -k tcp_hs tls_resumed failed_hs -t "Handshakes over Time" DoT.json

The optional parameter -k/--kind can be used to select which data should be plotted. The following values are supported.

  • active means the number of currently active established connections
  • tcp_hs means the number of TCP handshake attempts in the last second
  • failed_hs means the number of failed handshakes. All kinds of connection setup failures will be included, whether it's TCP handshake timeout, TLS negotiation failure or anything else.
  • tls_resumed means the number of connection that were resumed with TLS Session Resumption during the last second


Using the -- to separate a list of JSON files after specifying -k/--kind might be needed in some cases.

connections handshakes