Using Multiple Domains for Email

You can split your email across multiple subdomains which can each have their own SPF and DMARC handling (and DKIM). For example, your email domain landscape might look like this:

• smalltechstack.com : Your primary email domain used for “human” email such as GSuite or Office 365 (email comes from brian@smalltechstack.com)

• mail.smalltechstack.com : Used by account-based marketing (ABM) platform (email comes from brian@mail.smalltechstack.com)

• support.smalltechstack.com : Used by support ticketing system such as Zendesk. (email comes from brian@support.smalltechstack.com)

Benefits of spanning your email across multiple subdomains

• Your SPF records become shorter and easier to manage if separate email “channels” are used. This can be a way to avoid the SPF 10-lookup DNS limit.

• Each subdomain will build its own email reputation on the internet. This can avoid problems when your marketing team inadvertently “poisons the well” by ruining the email reputation of your primary email domain.