I'm working with a client to setup the SAP for their domain where the SAP domain is 'send.company.com' (well, similar anyway).

They are currently using a different marketing platform and will be migrating over to Marketing Cloud over a re-platforming phase.

In the meantime, they need to send from both platforms (their current marketing platform and Marketing Cloud).

I'm aware that there are multiple DNS entries used by the Sender Authentication Package (SAP), but from this list, the only two that are currently used by the existing platform are:

  • send.company.com (two MX records with a priority value of 10)
  • send.company.com (TXT record for SPF)

I know that the send.company.com MX record is only required for outbound email (SFMC uses a separate reply.send.company.com MX record to route replies). So, I should be able to add the additional MX records for Marketing Cloud (I assume the priority doesn't matter either, as it won't be used to route inbound mail).

Also, while there is an existing SPF record for send.company.com, which looks like this:

v=spf1 include:mktomail.com include:mailgun.org -all

I know that you can add additional include: keywords to existing records, e.g. this can be modified to:

v=spf1 include:mktomail.com include:mailgun.org include:cust-spf.exacttarget.com -all

Does anyone know if there is an issue with setting the same subdomain as SAP in Marketing Cloud, while also using it concurrently with a different marketing platform?

This would be quite a common scenario for customers migrating to Marketing Cloud and wanting to retain their existing subdomain. I believe that in theory, this should be possible.

  • 1
    Great Question and i am looking forward on the answer. When i would ask this question i would ask it on stackoverflow rather than on SFSE and mark it with the dns tag. maybe you get a faster and higher quality answer there. Aug 9, 2018 at 6:42
  • I don't have the technical reasons to back me up (which is why this is a comment, and not an answer), but I have been advised and have advised others to only utilize one ESP per subdomain. It IS possible, just potentially adds a large amount of risk. I have even had SFMC reject subdomains that are not exclusively used by them. So I would either use a different one completely for SFMC, or do not set up SAP until after Mailgun is taken off. Aug 9, 2018 at 13:28

2 Answers 2


From a reputation and operational point of view, it does make sense to keep the domains separate.

E-Mail reputation is not only based on IP, for some providers, notably gmail, domain reputation is more important, and apparently gaining importance (source for this is a Salesforce deliverability slide). So: especially during (IP) Warming, where you try and have a very controlled setup, if you run into reputation issues whose root cause you have to identify and mitigate, it will be hard to trace where the reputation problem originated.

In other words: the strategy of establishing a "clean" reputation during Warming by using your "new" setup (IP + domain) for sending only to your best performing subscribers first will not be possible. The ongoing, "old" mail provider's sendouts would be on the same domain and confound your efforts.

Of course it is also safer for the "new" sendout system to be isolated from the old, so no legacy debt is inherited.

So: While it seems technically possible, since the configuration is more complex but the risk is higher and standard practice for warming becomes impossible, this is generally discouraged and (in my experience) mostly avoided.

  • You make some very valid points which I didn’t consider, thanks for sharing! Aug 5, 2019 at 20:14

We encountered the same issue...Determining whether to use our existing domain, purchase one outside Salesforce, or buy the SAP.

The rep said that it should be a clean domain, and recommended that we start the warm process using our most "engaged" subscribers from the old system. In the end, we bought the SAP with domain and link wrapping just cuz it less effort.

We took their generic advice, and it worked :).

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .