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For cPanel & WHM version 11.52

(Home >> Mail >> Email Authentication)

Overview

cPanel’s Email Authentication features provide information about outgoing messages. This helps the server that receives the messages verify that the email comes from a trusted sender.

Note

Both the Domain Keys Identified Mail (DKIM) and Sender Policy Framework (SPF) authentication functions require that you use a DNS server for the domain name. For more information about DNS servers, review the terms of your hosting contract.

DKIM

DKIM verifies the sender and integrity of a message. It allows an email system to prove that spammers did not alter an incoming message while in transit (which means that it is not forged), and that the messages that your domains receive come from the specified domain.

  • To use DKIM, click Enable.
  • To disable DKIM, click Disable.

Note:

A warning may display that claims that the system cannot verify the server as an authoritative nameserver for the specified domain name . If either of the following scenarios is true, ignore the warning:

  • You designated the server as the authoritative DNS server for the domain name, but the change did not yet propagate.
  • The server does not view itself as the authoritative DNS server, but outside servers view it as the authoritative DNS server.

Add headers in DKIM

If you already use the DSO PHP handler and you enable DKIM, emails that you send will not display any information in the Return-Path, Reply-To, or From fields in the email header. As a result, DKIM will show that nobody is the sender. If you use a PHP script, manually add the headers.

The following PHP script example adds the missing parts to an email header:

<?php
$to      = 'nobody@example.com';
$subject = 'the subject';
$message = 'hello';
$headers = 'From: webmaster@example.com' . "\r\n" .
    'Return-Path: webmaster@example.com' . "\r\n" .
    'Reply-To: webmaster@example.com' . "\r\n" .
mail($to, $subject, $message, $headers);
?>

SPF

SPF attempts to deny spammers the ability to send email while they forge your domain’s name as the sender (spoofing). This authentication function adds IP addresses to a list that specifies computers that can send mail from your domains. It verifies that messages that your domains send come from the listed server, which reduces the amount of backscatter that you receive.

  • To use SPF, click Enable.
  • To disable SPF, click Disable.

Note

A warning may display that claims that the system cannot verify the server as an authoritative nameserver for the specified domain name . If either of the following scenarios is true, ignore the warning:

  • You designated the server as the authoritative DNS server for the domain name, but the change did not yet propagate.
  • The server does not view itself as the authoritative DNS server, but outside servers view it as the authoritative DNS server.

The spf_installer script

You can use the /bin/spf_install script from the command line to add an SPF record to all of a user's domains' zone files.

For more information about this script, read our The /bin/spf_installer Script documentation.

Advanced Settings

This section includes the following methods that you can use to configure SPF authentication:

Note:

  • Click Add to add domains.
  • Click Remove to remove domains.

SettingDescription
Additional Hosts that send mail for your domains (A):

The system automatically approves additional hosts that you specify to send mail from your domains.

Additional MX servers for your domains (MX):Specify MX entries that can send mail from your domains.
Additional IP Address blocks for your domains (IPv4):

IP addresses that you approve to send mail from your domains. The system automatically includes your server's main IP address in this list.

Note:

If you add IP addresses, you must use CIDR notation. (For example, 192.168.0.1/32)

Include List (INCLUDE):Specify additional domains to include in your SPF settings. This is useful, for example, when you send mail with another service.
All Entry (ALL):If you enable this setting, the SPF feature causes hosts that you do not define in the above lists to fail. If you disable this setting, the SPF feature does not cause undefined hosts to automatically fail. Instead, the system marks undefined hosts as Neutral. When a server receives mail from a neutral host, the server acts as if you disabled SPF. After you test the entries in the above lists and confirm that they are correct, enable this feature.
Overwrite Existing Entries:If you enable this setting, the system overwrites existing SPF entries.

Click Update to save your changes.