Network monitoring tools
netstat -ltupw and similar have limitations like namespace and thus they don't show the whole machine connections. (for namespace created with
ip we can see other connections with
ip -all netns exec ss).
The kernel state the connections here
/proc/net/tcp[udp][raw] and namespace connections can be seen here
What are the other possible connections that are not seen by ss/lsof/netstat and how to monitor them?