Why aren't my emails delivered?
If your emails are landing in spam or not reaching inboxes at all, it's time to run a SPF record check, DKIM record check, check DMARC record, and check reverse DNS to fix your email deliverability.
In this tutorial, we walk you through real examples of related keys like SPF, DKIM, and DMARC, and show you how to properly set them up for your domain. You’ll learn how to configure Reverse DNS (PTR records) using the Contabo Control Panel, how to add a valid SPF record via DNS, and how to generate and publish your DKIM keys. We’ll also explain how DMARC works and how it ties everything together for better email authentication and protection.
Don’t forget to test your setup using tools like MX Toolbox, Mail-Tester, and DMARC Analyzer to ensure everything is working. Perfect for Contabo users and anyone hosting their own mail server!
🕐 Timeline:
0:00 - 0:23 Introduction: Fixing email deliverability with SPF, DKIM, DMARC & PTR
0:23 - 0:49 What is Reverse DNS (PTR) and why it matters
0:49 - 1:17 Setting up SPF records correctly
1:17 - 1:35 Enabling DKIM for email authentication
1:35 - 1:48 Adding a DMARC policy and monitoring reports
1:48 - 1:58 Testing your email setup with MX Toolbox & Mail-Tester
1:58 - 2:21 Conclusion
Key Topics Covered:
What causes email delivery issues and why authentication matters
How to set up and check reverse DNS (PTR records) using Contabo’s Control Panel
What an SPF record is and how to create and validate it in your DNS settings
Explanation and setup of DKIM (DomainKeys Identified Mail) for email integrity
How to configure DMARC to define policy for handling failed SPF/DKIM checks
Tools to test and verify your SPF, DKIM, DMARC, and reverse DNS settings (e.g., MX Toolbox, Mail-Tester)
Important Notes:
Always set up a Reverse DNS (PTR) record to avoid mail rejections by major providers
SPF records must be accurate—include all mail servers or relays used, or legitimate emails might fail
Enable DKIM to cryptographically sign your messages and prove authenticity
Use DMARC to define how mail servers should treat emails that fail SPF or DKIM—and to get reports
Test all DNS and email authentication settings using tools like MX Toolbox, Mail-Tester, or DMARC Analyzer
Check your DNS propagation—some changes can take time to take effect across the internet
Regularly review and update your DNS records when changing email providers or adding new services
Contabo servers do not have automatic email backups—manually back up configurations and mail data
Visit our website: https://contabo.com
Support Center: https://contabo.com/support
#SPF #DKIM #DMARC #ReverseDNS #EmailAuthentication #Contabo #EmailSetup #VPSHosting #ServerAdmin #EmailDeliverability #DNSRecords