#!/usr/bin/perl -w
use strict;

my $line = 'client 127.0.0.1#47560: query: host.example.com IN AAAA';

my ( $part1)   = split (/#/,$line);
my ( $ipaddr ) = (split(/\s+/, $part1))[1];

print "  part1:  $part1\n  ipaddr: $ipaddr\n";
__END__
Prints:
  part1:  client 127.0.0.1
  ipaddr: 127.0.0.1

##</code><code>##

(undef, my $ipaddr) =  split(/\s+/, $part1);

##</code><code>##

my $line = 'client 127.0.0.1#47560: query: host.example.com IN AAAA';

(my $ipaddr) = (split/[\s#]/,$line)[1];

print "$ipaddr\n";
__END__
prints:
127.0.0.1