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What is DKIM?

Delivery Updated on August 3, 2021

By now you should be familiar with SPF Records and why they are essential to your sender’s reputation. However, the SPF Record is part one for basic authentication. Part two requires you to add a CNAME giving you dual authentication which helps improve your delivery success. Most ISP’s will utilize SPF and DKIM to validate incoming emails. If the email records are not verified, they will most likely end in the spam, junk folder, or even quarantined.

What is DKIM; DomainKeys Identified Mail, which grants an organization the responsibility for a message that is being delivered. The organization is either the main sender or the originator of the email message, the organization is known as the Identifier. The identifier’s reputation is responsible for email delivery success.

Ultimately DKIM verifies the domain through cryptographic authentication.

In plain English

Benchmark automatically authenticates the DKIM for email campaigns being sent from our service. Authenticating the DKIM for our senders helps secure the delivery through SPF filters.  Now, when you are using your email domain, we suggest adding a new CNAME and get the full benefit of double DKIM authentication. This way the ISP’s will not influence your reputation with that of other users sending emails using the same IP addresses, and only your domain’s information will display in the headers.

In the example below, you see the headers of an email after the CNAME has been published for the sending domain, it is using to send, however, it will only display your domain.

To take full advantage of double DKIM, you will need to add a CNAME for each of the domains you will be sending from. Updating your CNAME is the only step you will have to complete, it is not mandatory to update your CNAME.

Benchmark encourages you to update your DKIM and begin your path to email delivery success.

What you will need.

CName record: bmdeda._domainkey

Note: You can authenticate a CNAME for more than one sending domain.

How to add a new CNAME Below we listed the most popular domain/ web-hosting sites with instructions on how to add a new CNAME record. To see the hosting service’s help article, click on it’s name.

If you do not have access to update your CNAME or SPF Records in your web hosting site, you can contact your IT administrator or contact your web hosting service.  

  1. Log into your GoDaddy account.
  2. Then, click on the Avatar icon (top right corner) and select “My Products.”
  3. From the list provided choose your domain name to access the Domain Settings page.
  4. In the Additional Settings click on Manage DNS.
  5. Then, in the Records section, click Add.
  6. From the Type dropdown choose CNAME.
  7. Now, complete the following fields: a.    Host: bmdeda._domainkey b.    Points to: c.    TTL: 3600
  8. Lastly, click on Save to update your CNAME.  

  1. Click on the DNS Zone Editor icon from the Domains section.
  2.  Click on the domain you want to add a CNAME from the drop-down.
  3. Go down to  Add DNS Record
  4. Add the desired record name “bmdeda._domainkey”, to the Host Record field.
  5. TTL “3600” (can be left at its default setting)
  6. Choose the CNAME, from the drop-down labeled Type
  7. Enter into the Points To field.
  8. Then click on Add Record.

InMotion Hosting

  1. Log into your CPanel
  2. Select the Advanced Zone Editor button in the Domains section.
  3. Click on the drop-down menu, and select the domain in which you will add a CNAME.
  4. Then Click on the drop down option under Type, and select CNAME.
  5. Complete a.    Name : bmdeda._domainkey b.    TTL : 3600 3.    CNAME :
  6. Done  

  1. In the Control Panel, search for the domain name and proceed to the DNS Service interface.
  2. Click the Manage DNS link. The DNS Management Console will pop-up through which you may add any of the following Records:
  3. Click CNAME Records and in the next screen, click Add CNAME Record.
  4. There you would find 3 fields: a.    Host Name: bmdeda._domainkey b.    Value: c.    TTL: (can be left at it’s default setting)
  5. Click the Add Record button to submit your Record.

  1. Click the DNS Zone Editor icon, located in the Domains section.
  2. From the Drop Down box click on the domain you’re modifying
  3. Then, go to Add DNS Record
  4. Enter “bmdeda._domainkey”, in the Host Record Field
  5. TTL “3600” (can be left at it’s default setting)
  6. Click on CNAME from the dropdown menu.
  7. Enter into the Points To field.
  8. Then click on Add Record.

  1. Select Add Record.
  2. In the drop-down menu, switch the Record type to CNAME.
  3. In Domain name section, add bmdeda._domainkey
  4. In the Canonical name, add
  5. Then, select OK.
  6. Select Update in the pop up. (If you adding many records, you don’t have to select update until done.)

  1. Sign into your Cloudflare account.
  2. Select your domain, from the dropdown menu located on the top left
  3. Click on the DNS settings tab.
  4. Last, add the CNAME records:  

  1.  Go to the DNS Manager Settings page,
  2. Then, in the Host Aliases: CNAME Records section, select Add/Edit.
  3. You will see your current CNAME listed in an editable form.
  4. Enter or edit your subdomain in the Alias text box.
  5. For example, if you picked “” as your custom domain, enter “web”
  6. Or, if you’re using a root domain such as “” then you’ll want to enter “www”
  7. Select Other Host from the radio button
  8. Enter in the other host field
  9. Last, click Save Changes  

  1. Head into your Domain Central.
  2. Select the domain you want to add/edit a CNAME.
  3. Then, select DNS
  4. In Modify, click on CNAME records
  5. Enter the following a.    Host : bmdeda._domainkey b.    Points to :
  6. Last, click Add.  

  1. Click on the Domains tab, and select my domains list (Top Menu).
  2. Select the domain you wish to create a CNAME record for.
  3. Now, on the left select DNS Records.
  4. Here you will add the CNAME record, provided by Benchmark. a.    Select CNAME from the drop-down menu. b.    Enter your sending domain as bmdeda._domainkey in the Host field. c.    Add to the Answer field. d.    Enter the desired TTL, or just leave it default
  5. Finally, select the blue Add Record button.

Click Here to also learn about SPF Records FAQ. If you need more help understanding DKIM, please feel free to contact your Customer Engagement Specialist or our support team.

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