Re: ABOUT E-MAIL ID VALIDATION
Wednesday, June 21, 2006 07:22 PM
A complete regular expression that will accept all possible syntactically legal email addresses, and reject all non-legal email addresses (according to the relevant RFC, either son-of-821 or son-of-822) is going to be very, very complicated.
Even that is only going to tell you if the syntax is acceptable. It's not going to tell you if there really is an MX record in DNS for the given domain name (unless you do a DNS resolver query for that)..... and it's not going to tell you if there really is a mailbox by that given name, at that domain (and you can't tell that nowadays unless you actually send email to it and ask for a confirming response, and wait and check your return mailbox for the confirming response, after a few days)....