If you don't need all logs in a single file you could use $HOST or $HOST_FROM 
as part of the file name 


Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Sathish Sundaravel <sathish.sundaravel@gmail.com>
Date: 5/12/17 1:11 PM (GMT-05:00)
To: Syslog-ng users' and developers' mailing list <syslog-ng@lists.balabit.hu>
Subject: [syslog-ng] How to get list of IPs

Hi All

I have syslog Ng server running on Solaris platform and configured to receive or accept events from all unix servers in one single log file.

If I want to collect list of servers reporting to the log server , I have to manually extract list from a single log file which is too much time consuming . What would the best way ? 

Regards
Sathish