PHP Network getmxrr() Function

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The PHP Network getmxrr() function is used to retrieve the Mail Exchange (MX) records for a given domain name. It searches the DNS for MX records and stores the results in an array. The hosts array will include the domain names of the mail servers, and an optional weights array can be used to record the priority values of the mail servers.

Finding the mail servers that manage the transmission of emails from a domain is made easier with this function. The return value is true if MX records are found, and false otherwise.

Please be aware that this tool is not intended for email address verification. When there are no MX records, the domain itself serves as the mail exchanger. For older Windows systems, use PEAR's Net_DNS instead.

Syntax

Below is the syntax of the PHP Network getmxrr() function −

bool getmxrr ( string $hostname, array &$hosts, array &$weights = null )

Parameters

Here are the parameters of the getmxrr() function −

• $hostname − (Required) It is the domain name for which the MX records are to be fetched.

• $hosts − (Required) It is an array where the function stores the domain names of the mail servers found in the DNS records.

• $weights − (Optional) It is an optional array in which the process stores the priority (weight) of each mail server detected. If no weights are given, this parameter remains empty.

Return Value

The getmxrr() function returns TRUE if at least one MX record is found for the provided hostname. And returns FALSE if no MX records are found, or an error occurs (e.g., invalid hostname).

PHP Version

First introduced in core PHP 4, the getmxrr() function continues to function easily in PHP 5, PHP 7, and PHP 8.

Example 1

First we will show you the basic example of the PHP Network getmxrr() function to fetch and display the mail servers for a domain. It basically checks if MX records are available and prints them.

<?php
   // Domain name to check
   $domain = "tutorialspoint.com";
   if (getmxrr($domain, $hosts)) {
      echo "Mail servers for $domain:\n";
      print_r($hosts);
   } else {
      echo "No MX records found for $domain.";
   }
?>

Output

Here is the outcome of the following code −

Mail servers for tutorialspoint.com:
Array
   (
      [0] => alt1.aspmx.l.google.com
      [1] => aspmx.l.google.com
      [2] => alt4.aspmx.l.google.com
      [3] => alt3.aspmx.l.google.com
      [4] => alt2.aspmx.l.google.com
   )

Example 2

This PHP code fetches the mail exchange (MX) records for the given domain with the help of the getmxrr() function. After the entries have been sorted, the names of the sorted MX servers are displayed. This code can be used to identify and rank the mail servers of a domain.

<?php
   getmxrr("tutorialspoint.com", $mx_records, $mx_weight);
   for($i = 0;$i<count($mx_records);$i++){
      $mxs[$mx_records[$i]] = $mx_weight[$i];
   }
   asort ($mxs);
   $records = array_keys($mxs);
   for($i = 0; $i < count($records); $i++){
      echo $records[$i];
      echo '<br/>';
   }
?>

Output

Above Example gives the result as follows

aspmx.l.google.com
alt1.aspmx.l.google.com
alt2.aspmx.l.google.com
alt4.aspmx.l.google.com
alt3.aspmx.l.google.com

Example 3

Now in the below program we will use getmxrr() function to fetch MX records with their priority values. So it fetches MX records along with their priorities and displays both the mail servers and their weights.

<?php
   // Domain name to check
   $domain = "tutorialspoint.com";
   if (getmxrr($domain, $hosts, $weights)) {
      echo "Mail servers for $domain with priorities:\n";
      foreach ($hosts as $index => $host) {
         echo "Server: $host, Priority: {$weights[$index]}\n";
      }
   } else {
      echo "No MX records found for $domain.";
   }
?> 

Output

This will create the below output −

Mail servers for tutorialspoint.com with priorities:
Server: alt1.aspmx.l.google.com, Priority: 5
Server: aspmx.l.google.com, Priority: 1
Server: alt4.aspmx.l.google.com, Priority: 10
Server: alt3.aspmx.l.google.com, Priority: 10
Server: alt2.aspmx.l.google.com, Priority: 5