Office 365 Email Signature Management with Mail Flow Rules [Part 2: Apply the Rule]

We covered the reasons why you should include an email signature, and what information you should include in the previous post. However, Office 365 Email signature management is made possible with the application of mail flow rules. This enables the functionality to append email signatures at the server side, meaning that you get consistently applied signatures no matter what device you’re sending from. This enables company-wide standardisation and brand consistency.

You will need:

1. Office 365 Email Signature
2. Admin access to exchange mail flow rules
3. A signature/disclaimer encoded in html/css, with no more than 5000 characters (If you would like to know how to create one, read this post and follow the instructions.)

Step 1: Accessing Mail Flow Rules

1. In the top left corner, open apps, and hit Admin.

2. Then navigate to the Exchange admin centre.

3. Navigate to rules within the mail flow section.

Hit the plus icon and then create a new rule in the dropdown menu.

A new window will open with several options.

Step 2: Creating a Mail Flow rule for the Office 365 Email Signature

The new window that just opened should look like the following:

Office 365 Email Signature

Let’s go through the options in order.

1. 1. Firstly you will be asked to name this rule. It’s good practice to keep things organised. I suggest calling it something like “disclaimer” or “signature”.
   2. The next section is the “apply this rule if…” which is the section that controls what conditions need to exist for a signature to be appended. Select your preferred combination or, to cover all emails sent from within your organisation, select “The sender… is internal”.
   3. The next section, “do the following” asks you to select an action. You should select append a disclaimer, whereupon you should click on enter text, then paste in your html code.

The key part of this is the coded signature itself. An Office 365 email signature needs to be simple and lightweight as email clients are notorious for resizing and squashing email signatures. For more information on how to create a signature click here.

1. Next is a checkbox that asks “Audit this rule with severity level”. It’s up to you if you check this or not. The implication is that if checked, the rule will appear in reports and message traces. For more information click here.
2. Next it asks you to choose a mode for this rule. Select the radio button marked enforce. This option controls whether the rule will appear in message traces, which helps if you’re troubleshooting.
3. Click save.

Your new rule should appear within the list. You may need to promote or demote the priority of the rule using the arrow buttons, in case your signature rule conflicts with another rule.

Rules sometimes take a few minutes to propagate but eventually you will start to see a signature or disclaimer applied to your emails.

Step 3: Add Exceptions to the rule

You may want your signature to apply only in certain situations or for certain users. Mail flow rules are flexible. There are a range of conditions and exceptions you can use to tailor the rule so that it applies only when you want it to.

To prevent a stack of identical signatures at the bottom of your emails, you can insert an exception. Choose a unique word or phrase within your email signature. For example, your company registration number or part of the address. Edit your rule to include an exception, select “the subject or body matches…” and then enter a unique phrase included within your signature.

By doing this, the rule knows that a signature has already been applied before, so it doesn’t apply it every time a new email is sent.

If some staff need to be excepted from having a signature on their emails. Add an exception for the sender and add the individuals or groups you want excluded from the rule.