Community Knowledge Base

Domain Content Filtering

This settings page is only available to domain administrators and system administrators with the proper permissions.

Content Filtering at the domain level is a great way to perform actions that meet specific criteria for all users on the domain. For example, you can use content filters to delete messages with certain attachments (e.g., attachments with a .exe extension), forward messages from a specific email address to another account, or even alter the subject of specific types of email. Content filters are most commonly used to organize email by moving messages to specific folders. However, content filtering is extremely flexible and allows you to filter messages for users the way you want to.

Domain content filters take precedence over any user-generated content filters. That means domain content filters run before the evaluation of account-specific content filters.

NOTE: Some content filtering actions, such as a Forward action, do not work in conjunction with Plus Addressing as content filters are run BEFORE any plus addressing commands. Using both could lead to duplicate messages or other unwanted/unnecessary behavior.

Creating Domain Content Filters

When adding a content filter, the following cards will be available, each with options pertaining to the conditions you want to use for the rules, and the actions that are taken based on the conditions you set:


  • Name - The friendly name chosen to describe the rule.
  • Match Type - Because multiple conditions can be configured per content filter, SmarterMail provides the option to require ALL conditions to be met or only ONE of the conditions to be met in order for the rule's action to be triggered. Select the appropriate option from this list.
  • Enable wildcards in search strings (* and ?) - Enable this setting to allow wildcard functionality. Wildcards can be used to replace a specific word, phrase or character, where a question mark (?) represents a single character and an asterisk (*) represents any text. For example, if you wanted to block, and, you could enter sales?? If you wanted to block all sales addresses, you could enter sales* instead.


Click on New Condition to specify the criteria that triggers the rule's action(s). For each condition selected, you will be able to add specifications and enter any necessary details, as required. For example, if you choose to filter on 'From Address', you can enter one or multiple email addresses. If you choose to filter on 'Contains specific words or phrases', you can enter the specific text and choose to look for that text in an email's subject, message body, header, etc.

On many conditions, you also have the ability to reverse the logic of the criteria item by changing the Comparison selection. For example, imagine you only want to accept email from specific domains. You would choose the 'From specific domains' condition and set the Comparison field to 'Does Not Match". Any messages sent from domains that do not match what you've entered in the text box can be deleted.

Note: If you select a condition that requires a value to be entered, and the field is left blank, SmarterMail will ignore this rule.

The following conditions are available, separated by Condition Type:

From Address

  • From specific addresses
  • From specific domains
  • From trusted senders

Contains Specific Words or Phrases

  • Subject
  • Body
  • Subject or Body
  • From Address
  • To Address
  • Email header
  • Anywhere in message

To Address

  • To specific addresses
  • To specific domains
  • Only to me
  • My address in to field
  • My address not in to field
  • My address in to or cc field


  • Has any attachment
  • Specific filenames
  • Specific extensions
  • Over specific size


  • Flagged as high priority
  • Flagged as normal priority
  • Flagged as low priority
  • Message automated (no return address)
  • Sender authenticated
  • Message over size
  • Message under size
  • Received in date range
  • Sent through a specific server (by IP address)
  • Spam probability


Click on New Action to specify what should occur when an email triggers the content filter condition(s). Note: If you select an action that requires a value to be entered, and the field is left blank, SmarterMail will ignore this rule.

The following actions are available:

  • Delete message - Deletes the message so that it will never arrive at your Inbox. Note: Messages deleted through content filtering cannot be recovered.
  • Bounce message - Sends a message back to the sender of the email saying that the message was bounced. Note that the message is still delivered to you unless you choose to delete it as well. Note: If the system administrator has disabled bouncing, this option will function the same as the delete action.
  • Move message - Delivers the incoming message to the folder you choose from the dropdown list. Note: If you later delete that folder and leave the content filter active, the filter will automatically recreate the folder when the action is triggered.
  • Add Header - Adds an email header within the incoming message, which can be useful when performing additional filtering through Outlook or other email clients. Headers should be formatted like "X-someheadername: value"
  • Add text to subject - Appends a prefix to the subject line of the email. This is useful for categorizing emails as the subject line will be altered to include the text you specify in the text box.
  • Forward message - Forwards a copy of the message to another email address and leaves a copy of the message in your mailbox. Messages can instead be deleted from when forwarded by enabling the option. In addition, forwarded messages generally show the user who receives a forwarded message as the "TO" address. If the original recipients of the message need to be retained (i.e., the message in its original format needs to be forwarded), the "Keep original sender and recipients when forwarded" option can be enabled. When enabled, the TO and FROM addresses will look exactly the same as they did when the person forwarding the message received it.
  • Mark as read - Automatically marks the messages as read, which means it will not show up in your inbox, or any other folder, as unread.
  • Set Priority - Automatically elevates the priority of a message. For example, if you create a content filter that flags a message from a VIP, you may want to set the priority of the message to High as well to denote its importance.
  • Flag message - Automatically flags the message for follow-up. This makes it easy to find messages that have been acted upon by your content filter.