free
vmstat

sar 1 4 (-b)
iostat
mpstat
iotop

iftop
iptraf

pmap
pstree

https://linuxhint.com/monitoring-network-traffic-ntop-linux-command/
https://www.tecmint.com/tcpflow-analyze-debug-network-traffic-in-linux/
https://bobcares.com/blog/mrtg-monitoring-tool-for-linux/
https://www.cacti.net/
RRDtool
https://munin-monitoring.org/
https://www.nagios.org/

ss -s
ss -at '( dport = :22 or sport = :22 )'

iptables -L --line-numbers
iptables -D FORWARD 1

iptables -I DOCKER-USER -s 1.2.3.4 -j DROP

iptables -A INPUT -s <IP_Address> -p tcp --dport ssh -j DROP