#!/usr/bin/perl

use strict;
use warnings;

use Net::Subnet;

my $matcher = subnet_matcher qw(192.168.1.0/22);

while ( <DATA> ) {
	my @ips = m/(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)/g;
	next unless @ips;
	next unless grep { $matcher->($_) } @ips;
	print;
}

__DATA__
 
Sample output that I want to achieve: 

2017-12-08 07:01:39 127.0.0.1 GET /course-detail.aspx id=66&catColor=0 443 - 127.0.0.1 (e.g., IP) <server version etc. strings> 200 0 0 530
2017-12-08 07:01:39 127.0.0.1 GET /course-detail.aspx id=66&catColor=0 443 - 192.168.1.2 (e.g., IP) <server version etc. strings> 200 0 0 530
2017-12-08 07:01:39 127.0.0.1 GET /course-detail.aspx id=66&catColor=0 443 - 192.168.2.1 (e.g., IP) <server version etc. strings> 200 0 0 530
2017-12-08 07:01:39 127.0.0.1 GET /course-detail.aspx id=66&catColor=0 443 - 192.168.1.3 (e.g., IP) <server version etc. strings> 200 0 0 530
2017-12-08 07:01:39 127.0.0.1 GET /course-detail.aspx id=66&catColor=0 443 - 192.168.4.3 (e.g., IP) <server version etc. strings> 200 0 0 530

#Note that I only want to grep IP addresses (192.168.1.1-3) that are in the same netmask specified in $matcher