Working notes from the engineers who run a high-volume European mail platform. Each guide covers exactly what we have shipped in production — not vendor brochures, not regurgitated forum posts, just what actually works at scale today.
A walkthrough of every signal that decides whether your message lands in the inbox, the spam folder or nowhere at all.
Read more → AuthenticationHow the three protocols depend on one another, the right rollout order, and how to test the whole chain end-to-end.
Read more → SPFWhat an SPF record means, the syntax that matters, the lookups that bite you, and how to confirm yours actually works.
Read more → DKIMBuild the key pair, publish it in DNS, sign your outbound mail and prove the signature verifies on the other side.
Read more → DMARCFrom p=none to p=reject without breaking real mail, why alignment is the part everyone gets wrong, and what the reports tell you.
Read more → BlacklistsThe DNSBLs that actually move the deliverability needle, how to query each one yourself, and how to interpret a listing.
Read more → BouncesWhere each type comes from, why they matter for sender reputation, and the right way to handle them in your sending system.
Read more → DMARCThe XML structure, the records that matter, what each failure means, and the tools that turn the reports into something readable.
Read more → DiagnosticsRead the Received chain, decode the DKIM-Signature, understand Authentication-Results, and trace any message back to its origin.
Read more → DNSForward-confirmed reverse DNS in plain English, how to set a PTR with your hosting provider, and what breaks when you don't.
Read more → ReputationWhy a new IP needs a ramp, a four-week schedule that actually works, and the metrics you watch on the way up.
Read more → GmailHow to set it up, what each panel actually means, where the spam-rate threshold sits, and how to act on what you see.
Read more → FundamentalsMTA, MUA and MSA defined, how SMTP actually moves a message between hosts, and a tour of the MTAs you'll meet in production.
Read more → BlacklistsFind out who flagged you, fix the underlying behaviour first, then file a delisting request that the operators will actually approve.
Read more → Best PracticesThe legal lines under CAN-SPAM and GDPR, how mixing the two ruins delivery, and the infrastructure split that protects both.
Read more →Sender Policy Framework configured. Only authorised IP addresses may send for this domain.
Every outbound message is signed with a 2048-bit RSA key. Selector published in DNS and rotated regularly.
Policy set to reject. Aggregate reports collected and reviewed daily by the postmaster team.
For deliverability questions, abuse reports or feedback loops, write to postmaster@bouncezero.io or abuse@bouncezero.io. We typically respond within one business day.
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