All of your variables are global variables, so when they're set to $_, they will remain set. The way you have your loop designed, once you get all the way through the first set of data, those variables will retain their values, causing each iteration of the loop thereafter to call write (in other words, for every line of data afterwards, giving you an enormous number of extraneous reports).

If you want to continue with a design like this, you should un-set your variables after you write the report. This would allow them to fill up and your defined test to check the next occurrences (assuming you fix that test up as described by other posters--it's wrong how it is now).

I also strongly recommend you take a look at Net::WHOIS, which should make your life considerably easier.