PHP comes with a method to verify the existence of a mailbox you know what?

Source: Internet
Author: User
Tags mx record
PHP Check email address A lot of methods, more commonly used is regular expression, but it is more trouble, in PHP has a way to check the e-mail address, the following to do a detailed introduction, together to see it

I have PHP's own method to do the calibration.


Filter_var is a PHP built-in variable filtering method, provides a lot of practical filters, can be used to verify the integer, floating point, Mailbox, URL, MAC address and so on.

Filter_var if return false,

$email = ""; Var_dump (Filter_var ($email, Filter_validate_email));  $email = "ASB"; Var_dump (Filter_var ($email, Filter_validate_email)); $email = ""; Var_dump (Filter_var ($email, Filter_validate_email));


String (+) "" bool (FALSE) string (7)

For ASB This illegal mailbox format returned false, but for the passed, or slightly flawed ah.

But the general regular also through will think is a legal mailbox, then what method can be more accurate verification?


CHECKDNSRR is actually used to query the DNS record of the specified host, and we can borrow it to verify that the mailbox exists.

For, the MX record must not exist.

$email = "";  Var_dump (CHECKDNSRR (Array_pop (Explode ("@", $email)), "MX");  $email = "";  Var_dump (CHECKDNSRR (Array_pop (Explode ("@", $email)), "MX");


  BOOL (TRUE)  bool (FALSE)

Can see, very perfect, the only drawback is too slow, after all, is to do a network request. So it is not appropriate to synchronize to a large number of mailboxes to use this practice to verify.


We can engage Filter_var and CHECKDNSRR do calibration, for the vast majority of illegal mailbox will certainly be in the Filter_var when the time to hang off, the rest of the use

CHECKDNSRR further judgment.

$email _arr = Array ("", "");  foreach ($email _arr as $email) {    if (Filter_var ($email) = = = False) {      echo "invalid email: $email \ n";      Continue;    }     if (CHECKDNSRR (Array_pop ("@", $email), "MX") = = = False) {      echo "invalid email: $email \ n";      Continue;    }  }



However, it is important to note that because only the MX record is checked, it is only possible to judge that the is present, but it does not indicate that the Lastchiliarch user is present.

To more accurately determine the existence of the mailbox, it can only connect to the SMTP server to verify.

Introduces the mailbox authentication, PHP comes with the method how to verify the mailbox, URL, IP is legitimate, the following for you to introduce:

The main use is the Filter_var function .

Filter_var (variable, filter, options)
Variable required. Specifies the variables to filter.
Filter is optional. Specifies the ID of the filter to be used.
The options rule contains an array of flags/options. Check the possible flags and options for each filter.

PHP Filters

Example #1 A Filter_var () Example

<?phpvar_dump (Filter_var (' ', filter_validate_email)); Var_dump (Filter_var (' ') , Filter_validate_url, filter_flag_path_required));? >

The above routines will output:

String (() "" bool (false)
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