java: how can i verify an email address to be valid without sending a confirmation e-mail?

Question

when people register to my website i don't want to send them a verification e-mail, i just want to check if that e-mail exists. is there a way to do such a thing ?

using apache-tomcat and java as my main programming language.

thanks a lot!

Answer 1

No. There is no way to tell if an email address points to a valid destination. You can check basic syntax, and that the domain has a record in DNS, but that's all.

Answer 2

You can at highest use regex to check if the address is syntactically valid and/or looking up the MX records if the domain is valid, but this still does not guarantee that the email address is legitimate and belongs to the registrant in question. There is really no more reliable way than sending a verification email and waiting for confirmation in a short time-span.