sub getHostname
{
    my ($IpAddress) = @_;

    unless ($pingObj->ping($IpAddress, 1))
    {
        print "No response from $IpAddress\n" if $VERBOSE;
        return;
    }

    # Do the rest of the stuff here
}

##</code><code>##

    # This is the rest of the stuff.

    # Note the use of single quotes. It's not a performance thing - it's a
    # readability thing. Double-quotes are for interpolation. Single-quotes
    # tell the reader there's no interpolation here.
    my $Host = uc(gethostbyaddr (inet_aton($IpAddress), AF_INET))
        or '[FAILED]';

    # Get rid of everything starting with -UDP.
    # In your version, you captured everything before -UDP. Same difference.
    $Host =~ s/-UDP.*//;
    $Host = "${IpAddress}[NULL]" if $Host eq '';

    print "$IpAddress\t$Host\n" if $VERBOSE;
    return $Host;
}