You can add an HTML or plain text legal disclaimer, disclosure statement, signature, or other information to the top or bottom of email messages that enter or leave your organization. To do this, you create a mail flow rule (also known as a transport rule) that adds the required information to messages.


  • If you want the information to be added only to outgoing messages, you need to add a corresponding condition (for example, recipients located outside the organization). By default, mail flow rules are applied to incoming and outgoing messages.

  • To avoid multiple disclaimers being added in an email conversation, add an exception that looks for unique text in your disclaimer. This ensures that the disclaimer is only added to the original message.

  • Test the disclaimer. When you create the mail flow rule, you have the option to start using it immediately ( Enforce), or to test it first and view the results in the messaging log. We recommend testing all mail flow rules prior to setting them to Enforce.

Use the EAC to add a disclaimer or other email header or footer

  1. Open the EAC and go to Mail flow > Rules.

  2. Click AddAdd Icon, and then click Apply disclaimers.

    In the Exchange admin center, click Mal flow > Rules > Add  to create a rule

  3. In the New rule window that appears, enter a unique name the rule.

  4. In the Apply this rule if box, select the conditions for displaying the disclaimer. For example, select The recipient is locatedcondition, and then select Outside the organization. If you want this rule to apply to every message that enters or leaves your organization, select [Apply to all messages].

  5. Next to the Do the following box, select Enter text to enter the text of your disclaimer. For information about what can be added, see the next section.

  6. Click Select one, and select one of the Fallback options (See below).

  7. Specify the audit severity level to assign the severity level that appears in the message log.

  8. Select the mode for the rule. Select Enforce to turn on the disclaimer immediately, or select Test without Policy Tips to put a message in the message tracking log instead of adding the disclaimer.

  9. If you have additional conditions or exceptions that you want to add, select More options at the bottom of the page, which will show additional settings. For example, to add the exception that prevents multiple disclaimers being added in an email conversation, select Add exception and then select The subject or body > Subject or body matches these text patterns, and then specify the words or phrases in your disclaimer. Or, to put your disclaimer at the top of the email message instead of the bottom, in Do the following, select Apply a disclaimer to the message > prepend a disclaimer.

  10. When you're finished, click Save.

Format your disclaimer

    Here's the formatting that you can use in your disclaimer text.

Type of informationDescription
Plain text
The maximum length is 5,000 characters, including any HTML tags and inline Cascading Style Sheets (CSS).
HTML and inline CSS
You can use HTML and inline CSS styles to format the text. For example, use the <HR> tag to add a line before the disclaimer.
HTML is ignored if the disclaimer is added to a plain text message.
Use the <IMG> tag to point to an image available on the Internet. For example, <IMG src="" alt="Contoso logo">.
By default, Outlook and Outlook on the web (formerly known as Outlook Web App) block external web content, including images. Users need to acknowledge and download the blocked external content. We recommend that you test disclaimers that have IMG tags to verify they display the way you want.
User information for personalized signatures
You can use tokens to add unique attributes from each user's Active Directory account, such as DisplayName, FirstName, LastName, PhoneNumber, Email, FaxNumber, and Department. The syntax is to enclose the attribute name in two percent signs (for example, %%DisplayName%%).
For a complete list of attributes that can be used in disclaimers and personalized signatures, see the description for the ADAttribute property in Mail flow rule conditions and exceptions (predicates) in Exchange 2016

Fallback options for disclaimer rules

Exchange can't modify the content of some messages (for example, encrypted messages). For rules that add disclaimers to messages, you need to specify what to do if the disclaimer can't be added. This is known as the fallback option for the disclaimer rule. The available fallback options are:

  • Wrap: The original message is wrapped in a new message envelope, and the disclaimer text is inserted into the new message. This is the default value.

    • Subsequent mail flow rules are applied to the new message envelope, not to the original message. Therefore, configure these rules with a lower priority than other rules.

    • If the original message can't be wrapped in a new message envelope, the original message isn't delivered. The message is returned to the sender in an non-delivery report (also known as an NDR or bounce message).

  • Ignore: The rule is ignored and the message is delivered without the disclaimer

  • Reject: The message is returned to the sender in an NDR.

In the EAC, you select the fallback option in the rule action. In the Exchange Management Shell, you use the ApplyHtmlDisclaimerFallbackAction parameter.