How to validate an e-mail address

[INVIGOR]

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[katherine]

First you can test the pattern of the E-mail with a regular expression.
Next, you can attempt a connection with the SMTP server in charge for the domain, but do not actually send a mail, you just break the connection after the initial handshake. But it's not 100% foolproof.

 

[INVIGOR]

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[katherine]

I mean, the format of the E-mail address should conform to certain standards. For instance it should contain at least one of those characters: a-z, 0-9 . _ - then the AT symbol, then a properly formatted domain name. The whole set of rules is a tad more complicated than that actually.
RFC822 has all the gory details

 

[INVIGOR]

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[VirtualT]

Ah...Yes, the email address(es) I'm trying to verify follow the format. What I'm trying to ascertain, without actually sending an email, is if the email address is good, as in working/functional. Like pinging an IP address to see if you get a response, except an email address.

As the lady said, study up on the RFC, telnet to the mail server and see if it will accept an email for that address. It's the only way to do it.

 

[INVIGOR]

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[INVIGOR]

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[katherine]

Example: http://www.webdigi.co.uk/blog/2009/how-to-check-if-an-email-address-exists-without-sending-an-email/