First off THANK YOU all for the replies.
Here is some example data that a user would put into a web page which will be passed to this perl script.
I am writing this code to do some checks on DNS records before we (I work on a DNS team) add the records. I wanted to place the IP address from the input into a hash key and make the value the fqdn. This way I can dig against the IP and then see if what is returned matches whats in the hash. This would tell us that the record exists and matches what we expected and no action is needed. This is just one part of a larger DNS validation script I am writing (or attempting to write).
Thanks in advance for all your help