Hi all,
How to find number of connections to running in a port.
1. To find out the largest number of established connections with port number.
#netstat -na | grep ‘ESTABLISHED’ | awk ‘{print $4}’ | uniq -c | sort -rn
2. To find out the number of connections to port 80 [http] from each IP.
#netstat -plan|grep :80|awk {’print $5′}|cut -d: -f 1|sort|uniq -c|sort -n
Similarly, you can find out the number of connections to port 25 from each IP as.
#netstat -plan|grep :25|awk {’print $5′}|cut -d: -f 1|sort|uniq -c|sort -n
NETSTAT is the most useful tool to detect and determine whether a server is under DoS or DDoS attack (Distributed Denial of Service).
Thank you for checking
