you have:                      you want:

------------------------       ------------------------
date                           date
            (first file)                   (first file)
...data...                     ...data...
date                           ------------------------
------------------------       date

...data...                     ...data...
date                           ------------------------
------------------------       date

...data...                     ...data...
date                           ------------------------
------------------------       date

...data...                     ...data...
date                           ------------------------
------------------------       date
             (last file)                    (last file)
...data...                     ...data...
------------------------       ------------------------

##</code><code>##

                    $ip=$net.$counter;

##</code><code>##

while ( $counter <= 14 ) {
    $ip=$net.$counter;
    ...