use Regexp::Common qw/net/;                                                                    
my $ip_regexp = qr($RE{net {IPv4});                                                             
while(<DATA>)  {                                                                                              
  if (/($ip_regexp)/)  {                                                                                             
   my $ip_address = $1;                                                                           
    print "$ip_address\n";                                                                      
 }                                                                                             
}                                                                                               
                                                                                                
__DATA__                                                                                        
client 127.0.0.1#47560: query: host.example.com IN AAAA +