list network connections

netstat -na |awk '{print $5}' |cut -d "." -f1,2,3,4 |sort |uniq -c |sort -nr

ss -4 |awk '{print $6}' |cut -d "." -f1,2,3,4 |sort |uniq -c |sort -nr

These lines both returns all the connections open on the server and the destination:port.
On a proxy, it returns all the connections open towards the back-ends.