Validating the email Kolkata sex chat
Defence in depth only works if each level of your security onion is not rotten. Rejecting "[email protected]" because you want to defend against vulnerabilities in Sun's µ-law encoding doesn't make sense, does it? The reason I am here commenting is that Medicare Australia doesn't allow ".au" addresses, only ".com".
Generally speaking, a regular expression to validate email addresses is not an easy thing to come up with; at the time of this writing, the syntax of an email address must follow a relatively high number of standards and implementing all of them within a regular expression is practically unfeasible! Disclaimer: I am the lead developer for this component. "Next, it tries to contact the mail exchanger responsible for the given email address and begins a fake SMTP dialog with that server, emulating a real mail server.
This way it ensures that the server can handle emails for the address.
Assuming the e-mail passes validation, you can then pass it through another validator that could look for a known top-level domain, check the domain for an MX record, check for spelling errors from common domain names (gmail.cmo), etc.
Then present a warning giving the user a chance to say "yes, my mail server really does allow 🌮🍳🎁 as an email address." As for using exception handling for business logic, I agree that is a thing to be avoided.
The only way to truly verify whether an e-mail is valid is to send a test message.