SPF Explained
How Sender Policy Framework works, how to author a record correctly, and how to avoid the common failure modes.
Updated March 2025 · 9 min read
Resources
Knowledge base
Reference material for practitioners. The articles document how we handle each topic in production, not what a vendor blog would recommend. Updated as the underlying practice changes.
DKIM Explained
DomainKeys Identified Mail — how signing works, selector strategy, key length and rotation, and what DKIM cannot do.
Updated March 2025 · 8 min read
DMARC Guide
How DMARC ties SPF and DKIM together, staged policy rollout from monitor to reject, and how to use aggregate reports.
Updated March 2025 · 12 min read
Google Postmaster Guide
How to set up Postmaster Tools, what each metric means, and how to interpret the reputation graph.
Updated March 2025 · 8 min read
PowerMTA Optimization
VMTA design, queue tuning, per-domain policy, and the configuration mistakes that quietly cost inbox rate.
Updated February 2025 · 14 min read
IP Warm-up
How to warm a new IP without wasting weeks or torching reputation. Volume curves, segmentation, and when to stop.
Updated February 2025 · 10 min read
Dedicated vs Shared IP
When each is appropriate, the volume thresholds that make dedicated worthwhile, and the myths on both sides.
Updated February 2025 · 7 min read
Spam Complaints
What producers spam-marks, how to measure the rate correctly, and structural changes that reduce it.
Updated January 2025 · 8 min read
Bounce Management
Bounce categories, correct handling per category, and why silent retries are worse than hard fails.
Updated January 2025 · 9 min read
SMTP Authentication
The SASL mechanisms, when to use each, and how authentication interacts with TLS and IP allow-listing.
Updated January 2025 · 6 min read