Advanced Bounce Diagnostics & Troubleshooting

The "forensic" investigation. This section goes beyond simple codes and into log-level diagnostics, using raw SMTP logs from your MTA to find the exact moment of the "refusal" and the technical reason for it.

12 questions in this topic

How to read full SMTP transcripts for errors? What tools help debug delivery failures? How do you trace message hops with headers? What’s the difference between local and remote bounce sources? How can SPF/DKIM misconfigurations cause indirect bounces? How to test relays using telnet or openssl s_client? What is connection throttling, and how can you detect it? How to test message size and attachment limits? How do you verify reverse DNS (PTR) alignment for bounce analysis? What’s “policy rejections due to missing MX” really mean? How to interpret detailed error logs from Postfix or Exim? How can third-party bounce processors mislabel errors?

Questions about Advanced Bounce Diagnostics & Troubleshooting