$error=1 if ($hostname =~/\.$/); #trailing . is bad
my @labels = split(/\./, $good_string);
foreach my $foo (@labels) {
$error=1 if ($foo=~/^\-/); #can't start with a -
$error=1 if ($foo=~/\-$/); #can't end with a -
$error=1 if ($foo=~/^\d+$/); #can't be only numeric

last if $error;
}
if ($error) {
	print "A hostname!\n";
}
else {
	print "Not a hostname!\n";
}