SMTPKeep is a hosted SMTP relay that keeps copiers, scanners, NAS devices, scripts and line-of-business apps sending email through Microsoft 365 after Microsoft disables basic authentication for SMTP AUTH in Exchange Online. Devices keep using plain authenticated SMTP and point at smtp.smtpkeep.com; SMTPKeep sends each message from the organization's own mailbox through Microsoft Graph with OAuth, so mail lands in Sent Items and stays under the tenant's retention, journaling and DLP policies. No DNS, SPF or DKIM changes and nothing to install on site. Per-device logins, sender mailboxes, IP allow-lists and activity logs; port 2525 for devices limited to TLS 1.0 or 1.1; attachments up to 35 MB; messages are held encrypted and retried for up to 24 hours when Microsoft 365 is busy. Built for IT admins and MSPs, with one dashboard for many tenants. Priced per tenant with a 14-day free trial.
