How to validate the username of email address?

Question

I have my code below, I'm able to validate the domain but unable to validate the username even the domain name is valid.

For example:

mon@hotmail.com  --- valid domain valid username  ---- pass
aksjdsk@hotmail.com ----- valid domain invalid username  ---- failed

Appreciated if anyone can help.

function domain_exists($email, $record = 'MX'){
list($user, $domain) = preg_split('/@/', $email);
return checkdnsrr($domain, $record);}

if(!domain_exists($email)){
echo "<script type='text/javascript'>window.alert('No have such email,invalid Domain. please enter valid email address!')</script>";
echo "<script type='text/javascript'>window.location='register.html'</script>";
exit;}

function user_exists($email, $record = 'MX'){
list($user, $domain) = preg_split('/@/', $email);
return checkdnsrr($user, $record);}

if(!user_exists($email)){
echo "<script type='text/javascript'>window.alert('No have such user, please enter valid email address!')</script>";
echo "<script type='text/javascript'>window.location='register.html'</script>";
exit;}

I'm pretty sure DNS doesn't contain information on email *users*... — Oliver Charlesworth, Oct 23 '13 at 10:09
there is no successful way to invalidate username like that .. although you can make blacklist for username like that — NullPoiиteя, Oct 23 '13 at 10:10

score 2 · Answer 1 · answered Oct 23 '13 at 10:11

The only way to know is a particular username at a domain name exists, is to send them an email, and have them click a link that is provided in that email.

abuse@hotmail.com, x@x.org and obama@whitehouse.gov may well all be valid, doesn't mean that they requested the email, or care to use anything you might send.

score 1 · Answer 2 · edited Apr 30 '17 at 21:32

1

Some sites send activation e-mail. Maybe you must use this.

generate an activation code for e-mail like this

<?php $activation_code= md5(microtime().rand(1,9999999)); echo$activation_code; ?>

and then register this code database with username's id or e-mail and send e-mail this code. if user don't click it in some time then delete the user or block..

edited Apr 30 '17 at 21:32

josliber

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answered Oct 23 '13 at 10:21

BARIS KURT

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How to validate the username of email address?

2 Answers2