title: In Logstash, how to get public IP address of a client as field
body: <p>I am sending logs from my node to logstash using file beat.
  There are multiple such a kind of nodes who are sending logs to logstash using file beat.</p>
  
  <p>Basically I want to know the public IP address of my node so that I can plot a visualization in KIBANA with geoip based location.</p>
  
  <p>And as my node is behind NAT, I can't print IP address as part of my log entry (eg., syslog entry); because locally I know only private IP of the node.</p>
  
  <p>Is there any way that logstash can automatically know my node's IP address and insert it as a elastic search field?</p>
  
  <p>Theoretically it should be possible as when logstash gets the information from beats, he should be knowing the IP address from where he is getting that.</p>
  
  <p>Thanks in advance.</p>