Email whitelist: whitelists against spam

An email permission list (email whitelist) brings together senders or domains considered reliable whose messages are not blocked by the anti-spam filter. THE whitelisting checks if the sender is on this list and, if so, the message is delivered, even if it normally matches filter criteria. This helps ensure reliable receipt of important emails.

What is an email whitelist?

An allowlist is the opposite of a blacklist. Instead of blocking senders, IP addresses or domains, passlist contains only entries explicitly allowed. These could be websites, programs, file extensions, email addresses or even people. In summary: everything is blocked except what is on the list.

These lists are often used in firewalls. The administrator manually adds authorized communication targets, and only these contents can pass through the firewall. Everything else is blocked. Similarly, to protect individual computers, only authorized applications can access the device through a whitelist. These lists allow, for example, to only authorize certain types of files or to block others, depending on their extension (.docx, .xlsx or .exe). The same principle applies to the messaging management or to the youth protectionwhere only precisely defined IP addresses or domains are allowed.

On a technical level, two sets of data are essential for email distribution:

• The MX Record of a domain. MX means Mail Exchange and tells the client where to contact the mail server for the domain in question.
• THE email header information (often hidden) allow you to retrace the path of a message and check whether the displayed sender corresponds to the real sender. Spammers frequently manipulate fields From And Return-Path to steal an identity.

What are the advantages of whitelisting?

Whitelists allow centrally manage user interaction permissions. This ensures clarity and security regarding authorized programs, web services and senders. Content deemed unsafe or illegal is automatically filtered and quarantined. This way, spam emails can be significantly reduced. The essential condition is to know and define the authorized interactions. The major advantage of this method is that no unknown programs, files or senders can access the protected system.

Whitelisted email recipients still receive messages from these senders. Emails from authorized contacts never land in the spam folder, but directly in inbox. It is also possible to invite recipients, via a short message in the email, to add the sender to their contacts to guarantee the correct future reception of messages.

The creation of a passlist can be done at several levels: via the Internet service provider, a third-party service provider (free or paid) or directly by the user.

Many suppliers allow you to manage your own blocking lists and white lists. However, you should know that, depending on the configuration, the entries in a blacklist may take priority over those in a whitelist. A customer account is required to create or modify these lists.

A well-known independent provider is DNSWL.ORGa volunteer-run anti-spam organization that offers free whitelist and public up to a certain number of requests. If you are registered, you get a detailed overview of the recorded data, including IP range and hostnames.

Among the paying providers appear Spamhouse, Return Path and the Certified Senders Alliance (CSA). The latter offers one of the most used whitelists in German-speaking countries. To be registered, you must meet certain criteria, in particular:

• Responsible and responsive management of abuse detected on its own network
• A correct and up-to-date registration in the Whois directory
• Lack of spam complaints

New registrations are verified by providers from public and private sources. One of the essential aspects is to determine if spam incidents have already been reported for a domain or IP address. Networks with public access generally receive a lower level of trust, while those subject to strict administrative control receive a higher level. Each service provider also defines its own criteria for removing an entry from the white list.

Create an email whitelist: practical guide depending on your email service

Although the technical principle of a whitelist remains generally identical, the concrete procedures vary depending on the supplier. On mobile devices, the process is almost the same. It may happen that certain fields are not displayed in the email client; simply activate them in the settings or menu. On a touch screen, pressing “From” displays the real email address of the sender (without opening the message directly). Here is a brief overview of the steps to follow:

Gmail

• Log in to your Google account and open the inbox.
• Place the cursor on the sender of the message; a pop-up window appears.
• Select “Add to Contacts” (avatar icon with a sign +).

Outlook (Microsoft 365, Outlook 2019 and 2016)

• Open the sender's email to add to the whitelist.
• Click on the three-dot icon.
• Select “Spam” then “Never block sender” or “Add to approved senders list”.

Outlook (2013, 2010)

• In the message preview window or directly in the open message, right-click on the address of the relevant sender.
• From the context menu, select “Spam” then “Never block sender” or “Add sender to safe senders list”.
• You can also open “Spam Options” to adjust the filtering level and manage the passlist and blacklist directly in Outlook.

Thunderbird

In Thunderbird, it is possible to create, in addition to the standard directory, other address books, for example a book entitled “Whitelist”.

• Select and open the message to add to the whitelist.
• Right-click on the sender's email address.
• Choose “Add to address book” then confirm with OK.
• Check in the account settings, under “Spam settings”, that the option “Do not mark messages from my address books as spam” is activated.

Yahoo!

• Open the message concerned.
• Click on “Add to contacts” (button next to the “From” field).
• Confirm to save the sender in the authorized contact list.

Apple Mail

• Select and open the email preview.
• Hover over the sender's name (first line of the message header) to display the drop-down menu.
• Click on “Add to Contacts” to save the address.
• Tip: in “Mail > Settings > Rules”, it is also possible to create specific rules to automatically authorize emails from certain addresses.

IONOS

With an IONOS email whitelist, you can ensure that emails from certain senders are always delivered to IONOS Webmail and do not end up in the spam folder. To do this, log in to your IONOS customer account and open the settings menu. Then go to the anti-spam settings.

In the section “ Safe Shippers », add the email addresses or domains that you want to include in the IONOS whitelist. All messages from these senders will then automatically be considered trustworthy.

Thanks to the IONOS whitelist, you maintain control over your email traffic, avoid unwanted filtering and guarantee the reliable delivery of your important messages.