What is a suppression list?

Suppression lists prevent emails to email addresses that have opted out, filed an abuse complaint, or are no longer valid (bad email address).

About suppression lists

When a contact unsubscribes from a database, the contact is added to the database suppression list and their status on the Suppression List Summary page shows as opted in, because they are opted in to the suppression list. This opt-in date shows when the contact unsubscribed from the email list.

Suppression can also occur for other reasons, such as an address containing a domain or prefix that is on the email blocking list (in Acoustic Campaign, go to Settings > Email Blocking) or an address that is on the global suppression list (clients do not have access to this list).

While a contact's email address is on an organization-level master suppression list, he or she will not receive email from any database in the organization. If a contact's email address is on a database-level suppression list, he or she will not receive email from that particular database.

Note: By default, your organization contains an organization-level suppression list, called the master suppression list.

You cannot add a field to a suppression list. Unlike a regular database, a suppression list only stores email addresses. Other than system fields, only the Email field is included. No other field can be added.

Organization impacts

The master suppression list in its default setting collects all abuse complaints, undeliverables (invalid mailboxes), and opt outs from any email sent using any database in the organization. These addresses are then excluded from any email going out of the organization.

The opt outs and abuse complaints for an email are also flagged (as opted out) on the database used to send that email. The two most common requests for suppression settings are detailed below:

  • To keep opt-outs separate for each database.
  • To replace the organization-level suppression list.

Permissions are set so you cannot perform these requests without contacting Client Support. This is to prevent you from accidentally making changes to these settings that could negatively impact your deliverability.

Types of suppression lists in Acoustic Campaign

The different types of suppression lists are:

  • Organization level
  • Database level (list level)
  • Email level
  • MD5 encrypted

Database-level suppression

Database-level suppression maintains all abuse complaints, undeliverables, and opt-outs on separate suppression lists assigned to each individual database in an organization. This suppresses these addresses from all emails sent, using the database with which the suppression list is associated. This is not a commonly used configuration.

Note: These suppression lists are not created by default and must be created by the user.

Organization-level suppression

Only allows the user to select suppression list as the database/list type.

Maintains all abuse complaints, undeliverables, and opt-outs on a single master suppression list. This suppresses these addresses from all emails sent out of this organization. This is the default setting for all organizations.

Note: The master suppression list is created by default upon organization setup.

Organizations can create and use multiple suppression lists; however, only one organization-level suppression list can be active at a time.

Email-level suppression

Applied at send time for a specific email. Unlike organization level and database level suppression lists, contacts are not added to this list upon opt-out. Email-level suppression lists are intended to add additional suppression to an email. If a contact opts out of the list, they are marked as opted out and added to the organization suppression list or database level suppression list if activated.

MD5-encrypted suppression

MD5-encrypted suppression lists provide an added layer of security if you are transferring your suppression list to another company and you don't want them to be able to send to it. MD5-encrypted lists are used by organizations or agencies that send emails for third parties, such as an organization that sends medical information on behalf of a health care system.

In compliance with the recommendation from the Email Sender and Provider Coalition (ESPC), organizations can now import, export, and use MD5-encrypted suppression lists within Acoustic Campaign. However, MD5 encryption can only be selected when creating a suppression list in an initial import.

When you are importing data into a new suppression list, select the The import file specified contains MD5 hash coded email addresses check box. After the import is complete and the new suppression list is created, future imports will also allow and require the MD5 format.

Using suppression lists in queries

It is not possible to create a query based off the master suppression list. However, the master suppression list can be exported, re-imported as a database, and then a query is able to be created from the database.