Tag Archives: netstat

use netstat to monitor receive queue Recv-Q

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# i=0; while true; do i=$(($i+1)); echo $i ==============================; netstat -natlp | grep ^tcp | sort -nk1 | awk '{ if($2 != 0) {print}}' ; sleep 1;  done;
1 ==============================
2 ==============================
3 ==============================
4 ==============================
5 ==============================
tcp      100      0 10.0.3.167:22           198.21.8.23:53477       ESTABLISHED 99304/sshd: fordodone
6 ==============================
7 ==============================
8 ==============================
9 ==============================
tcp    43520      0 10.0.3.167:53877        10.0.9.55:3306          ESTABLISHED 119789/mysqldump
10 ==============================
11 ==============================
12 ==============================
13 ==============================
14 ==============================
15 ==============================
16 ==============================
tcp6       1      0 10.0.3.167:80           198.21.8.23:65114       CLOSE_WAIT  3880/apache2    
17 ==============================
18 ==============================

get current client IP addresses from web farm

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To see what common IPs are connecting to your web farm, ssh to all of the servers and get a list of clients. Then sort it until you see most busy clients.

# for i in `seq 401 436`; do ssh www$i "netstat -natp | grep EST | grep apa | grep ":80 "| awk '{print \$5}' | cut -d : -f1"; done | sort | uniq -c | sort -nk1 | tail
      3 10.0.0.1
      3 10.0.0.10
      3 10.245.34.2
      4 10.29.45.89
      5 10.111.111.111
      5 10.239.234.234
      5 10.1.1.1
      5 10.2.2.2
      6 10.3.3.3
     10 10.100.100.100
#

The list shows the number of connections, and the client IP.