Knowing the number of active connection to server
Display count of Established connection to server
netstat -ntu | grep ESTAB | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -nr
http://www.mydigitallife.info/2007/12/13/how-to-find-and-check-number-of-connections-to-a-server/