From Northworks Solutions:
dToolz is an advanced Windows software program with a variety of features relating to domain verification and DNS resolving. It includes a Domain MX verifier, a RDNS checker and a Catch-all verifier. The Domain MX verifier will perform MX lookups on the domains in a list to determine which domains that can accept emails. The RDNS tool will perform IP to Host resolving and save the results in a few different ways. And the Catch-all verifier will find out which domains that accepts emails to any random username on that very domain. Checks a maximum of 25% and 200 records.