for $i (keys %data) {
    push (@ips, $i); 
   for $j (keys %{$data{$i}{ports}}) {
     # push (@names, $data{$i}{cname}); # <--wrong
     push (@names, $data{$i}{$j}{cname});
   }
}

# compare that with this code that uses logical names 
# if also uses my to localise variable scope, strict compliant too

for my $ip (keys %data) {
   push @ips, $ip; 
   for my $port ( keys %{$data{$ip}->{ports}} ) {
      push @names, $data{$ip}->{$port}->{cname};
   }
}

##</code><code>##

# make %data

require Data::Dumper;
print $q->header;
print $q->escapeHTML(Dumper(\%data));
exit;