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The Apache web server in my RHEL shows many requests in R (..reading..) state. I want to find the client IPs that are making Apache wait in reading state. Specifically: I want to find out all the client IPs that are spending too long to send the request.

The server-status module is not enough. Server status does not show the client information when the PID is in reading state.

2 Answers 2

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Try using netstat program with the -l flag to get a list of listening process. You probably want to run it with sudo so that you can use the -p flag to get process PIDs. You might also want the -t flag to only show tcp sockets instead of tcp and udp. Sometimes the -n flag is nice to show only port numbers and IPs without resolving them to services and names.

After that it's a matter of greping for just your apache process and then extracting the PID from the output columns:

sudo netstat -lntp | grep httpd | awk -F '[/ ]*' '{print $7}'
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To find out the details about connections which are spending more than 15 seconds in HTTP request reading phase, I wrote this command:

links http://localhost/server-status | tee | grep "..reading.." | awk '{if ($6>15) print "lsof -a -n -i TCP -p"$2}' | sh |  grep -E "TCP.*(ESTABLISHED)"
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  • What does links do? What distro are you using where that's available? Oct 15, 2016 at 23:11
  • its a command line web browser
    – allanlaal
    Mar 5, 2017 at 1:24
  • This requires Apache module mod_status to be enabled as described here: serverfault.com/questions/350559/…
    – MrG
    Nov 28, 2017 at 13:23

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