Can I authorise my whole domain name to send through your SMTP service?

You or your organisation can authorise your whole domain as a wildcard email address rather than individual addresses (for example, *@example.com).

Before a customer-owned sending domain can be authorised, it must meet all three of these authentication requirements:

  • Publish one valid SPF record that includes AuthSMTP and every other legitimate sending service for the domain.
  • Publish a valid DMARC record. p=none is acceptable as a starting monitoring policy, but the longer-term plan should be to progress to p=quarantine and then p=reject after checking reports and correcting alignment for every legitimate sender.
  • Configure and verify AuthSMTP DKIM signing for that domain using the values generated by the AuthSMTP Control Panel.

This AuthSMTP baseline is deliberately stricter than DMARC's technical minimum, under which either aligned SPF or aligned DKIM can be enough for a message to pass. Authentication requirements at mailbox providers are becoming stricter, and an account that sends a small volume today may send at high volume later. Requiring SPF, a published DMARC policy and verified AuthSMTP DKIM gives every authorised domain a stronger foundation from the start.

DKIM adds a cryptographic signature to messages sent through AuthSMTP, allowing receiving systems to verify the signing domain and detect changes to signed content. DMARC connects authentication results to the domain visible in the From address and provides reporting and policy controls. Used together, they improve trust in genuine mail and reduce the risk of successful spoofing or impersonation using your domain.

SPF must authorise AuthSMTP and every other legitimate sending service without creating a second SPF record. SPF is required in addition to, not as a substitute for, the AuthSMTP DKIM and DMARC requirements.

You must prove that you control the domain through its DNS records. The domain must have valid DNS and MX records, and every address used in the From, Reply-To or return path must be valid and able to receive replies, bounces and error messages.

To add a whole domain name to your AuthSMTP account click here.