This is to show a few tools that can be used to monitor traffic on an Alpine Linux firewall, either to track down specific issues, to establish a traffic baseline, etc. This is not a comprehensive guide to each tool, since that can be found elsewhere on the internet.
Available from main repository (v1.9, v1.10, v2.0, edge). No switches are needed. Good tool for seeing statistical view of traffic, either layer 2 or 3.
Available from main repository(v1.9, v1.10, v2.0, edge). No switches needed. Graphical view of traffic by connection.
Available from main repository (edge). No switches needed, another graphical traffic viewer by connection.
More are available, but that is a start...