Examine your domain's DNS records including A, MX, TXT, CNAME, NS and more.
Verify your SPF records to ensure only authorized servers send email on your behalf.
Check your DKIM configuration to validate email signatures and prevent spoofing.
Analyze your DMARC policy for domain-based email authentication and reporting.
Check if your mail server IP is listed on any DNS-based blacklists.
Send test emails to validate SPF, DKIM, and DMARC configurations.
Analyze email message headers to trace delivery paths and diagnose issues.
Scan open ports on your server to verify firewall and service configurations.
Measure your internet connection speed with independent testing tools.