A step-by-step guide to self-hosting an email server using Postfix in Docker, covering DNS setup, email forwarding, DKIM, SPF, and DMARC configuration. The author chose this path to avoid paid services like Mailgun or SendGrid, estimating costs at ~$6/month for a VPS. Key topics include port 25 unblocking with hosting providers, reverse DNS setup, assembling DKIM public keys for DNS TXT records, merging SPF records, and using tools like Mail Tester and EasyDMARC to verify deliverability. The guide also addresses sender reputation building and patience required for new servers to gain trust.
Table of contents
High-level designRequirementsPreparationBasic DNS setupEmail forwardingPostfixSend a test emailReverse DNSDKIMSPFDMARCHave patienceConclusionSort: