Postmark’s help on Sender Signatures; the main way we verify sending addresses
- How can I check if my DKIM and SPF records are valid?
- Adding DKIM and SPF records to Go Daddy
- What is SPF?
- How do I send email on behalf of my customers?
- Adding a custom Return-Path domain
- What is DKIM?
- Adding DKIM and SPF Records to DigitalOcean
- How do I verify a domain?
- How can I update SPF when a record already exists?