Logging unique IP addresses your Java code communicates with

Recently I needed some utility that would log all unique IP addresses all the Java processes on a server communicated with.

I googled a bit and did not discovered nice and easy solution for this. So I decided to do some bash-fu and wrote the following script.

while true do netstat -nput 2>/dev/null | grep 'java' | tr -s ' ' | cut -f5 -d ' ' | cut -f1 -d ':' | uniq | while read -r ip; do grep -qxF $ip ip.log || echo $ip >> ip.log; done sleep 5
done

Let’s go over it step by step to explain what it does:

• while true – this means that when executed it will run until stopped, easy
• netstat -nputw 2>/dev/null – netstat prints network connections
  • -n – show numerical address instead of trying to resolve host names
  • -p – show PID of the program
  • -u – include UDP connections
  • -t – include TCP connections
• grep 'java' – only take those lines that have Java in them (PID contains java for Java apps)
• tr -s ' ' – replaces each sequence of spaces with a single space
• cut -f5 -d ' ' – takes fifth column (separated by spaces)
• cut -f1 -d ':' – takes first part (separated by 🙂 – removes port
• uniq – makes the list unique
• while read -r ip; do grep -qxF $ip ip.log || echo $ip >> ip.log; done – adds it to a log file if it does not contain it already
  • grep -qxF
    • -q – quiet, do not write anything to standard output
    • -x – select only those matches that exactly match the whole line
    • -F – interpret PATTERNS as fixed strings

Hope this will help you or if you have a better solution please let me know.

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原文链接：Logging unique IP addresses your Java code communicates with