Number of open connections per ip.

netstat -ntu | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
Here is a command line to run on your server if you think your server is under attack. It prints our a list of open connections to your server and sorts them by amount. BSD Version: netstat -na |awk '{print $5}' |cut -d "." -f1,2,3,4 |sort |uniq -c |sort -nr
Sample Output 
20 81.49.60.x
21 116.212.111.x
26 65.184.224.x
31 189.61.36.x
84 89.180.3.x
212 127.0.0.1

14
By: tiagofischer
2009-03-28 21:02:26
awk cut netstat sort uniq sort awk uniq netstat cut
4

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What Others Think

Header lines from netstat are mixed in. tail -n +3 fixes that: netstat -ntu | tail -n +3 | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
gthb · 831 weeks ago
can you output the connected port too?
Ovidiu · 759 weeks and 5 days ago
This command will output how many connections per port netstat -tuna | awk -F':+| +' 'NR>2{print $5}' | cut -d: -f1 | sort | uniq -c | sort -n
tdw82 · 720 weeks and 5 days ago
No need for tail or cut netstat -ntu | awk -F"[ :]+" 'NR>2{print $6}'|sort|uniq -c|sort -nr
LightningCrash · 712 weeks and 5 days ago

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