Netstat Connection Check

netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n | tail
This command does a tally of concurrent active connections from single IPs and prints out those IPs that have the most active concurrent connections. VERY useful in determining the source of a DoS or DDoS attack.
Sample Output
[root@vps10 root]# netstat -ntu | awk '{print $5}' |  cut -d: -f1 | sort | uniq -c | sort -n | tail           
      8	200.217.193.102
      8	82.101.189.139
      9	84.195.188.60
     11	189.63.98.3
     11	60.28.166.169
     13	24.227.166.150
     15	200.214.44.134
     16	189.92.141.77
     22	189.14.101.44
     31	127.0.0.1

2
By: TuxOtaku
2009-02-16 15:48:27

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What do you think?

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