Show all TCP connections, numeric (IP), process and app name, extended
netstat -antpe
Show all UDP connections, rest as above
netstat -anupe
Show all Unix, rest as above, full extended
netstat -anxpe
Crude DDoS test
netstat -an | grep ‘tcp\|udp’ | awk ‘{print $5}’ | cut -d: -f1 | uniq -c | sort -n
List listening and non-listening connections, numerical, TCP & UDP, extract the IP column, separate from port, count the occurances and finally sort numerically.