Check an email address to see if it's valid
The purpose of this page is to validate a sender's email address (through a domain MX record lookup+smtp RCPT TO: session) to see if an automated sender validity filter would help in reducing spam
After running a few thousand spam return addresses through a script using the core function, I decided it would help for only 25%-50% of the incoming spam junk. But that might change, so here it is for public enjoyment ;-)