You need to setup DKIM for Salesforce if you want Salesforce to send properly authenticated emails on behalf of your domain. Skipping this can cause issues in email delivery and increases the chances of your emails being flagged as spam.
In order to enjoy seamless email delivery while using Salesforce to send emails, and making sure your receivers receive those emails signed with your domain name, learn how to setup DKIM for Salesforce.
Enable DKIM signing for your domain in Salesforce
1. Navigate to the Salesforce Setup menu and type in DKIM in the quick find.
2. Click on DKIM Keys.
3. Select Create New Key.
4. Now choose your key size, and for the primary DKIM selector enter sfdc1. For your alternative selector enter sfdc2.
Note: You can use the default values of s1 and s2, but they may already be in use by other another service. If s1 and s2 selectors are already in use by other keys, please choose other custom names for the selectors. (sf1 and sf2, salesforce1 and salesforce2, etc).
5. Enter your domain name, in this case, we have used yourdomain.com.
6. You can choose your domain match according to your preferences. In this case, I have chosen to go with the exact match.
7. Click Save.
8. It may take some time for Salesforce to generate the 2 CNAME records. Refresh your page, and you will see something like this:
9. Copy the values for your new records (the values are those after CNAME) and add the DKIM keys in Valimail Enforce.
Go to your domain's Configuration page in Valimail Enforce and publish the newly created DKIM key.
a. Click on Add a DKIM key and fill in the info from the newly created Salesforce keys and then click Add.
10. After publishing the DKIM keys in Valimail Enforce, please return to the Salesforce console and click on the Activate button to activate the DKIM keys.