← Back to Email Authentication Knowledge Base ⚡ Production Engineering Runbook • Updated for 2026 ISP Mandates • 15 min read Executive Engineering Runbook Technical Overview & Production Verification Scope Use a year-based selector naming convention so key age is visible from the selector name — mail2026 clearly indicates when the key was generated. Generate […]
← Back to Email Authentication Knowledge Base ⚡ Production Engineering Runbook • Updated for 2026 ISP Mandates • 15 min read Executive Engineering Runbook Technical Overview & Production Verification Scope Each aggregate report covers one 24-hour reporting period and contains: count: Number of messages from this source IP during the reporting period. A legitimate high-volume […]
← Back to Email Authentication Knowledge Base ⚡ Production Engineering Runbook • Updated for 2026 ISP Mandates • 15 min read Executive Engineering Runbook Technical Overview & Production Verification Scope You can identify your current key length: A DKIM key rotation that also upgrades from 1024-bit to 2048-bit is doubly valuable and should be prioritised […]
← Back to Email Authentication Knowledge Base ⚡ Production Engineering Runbook • Updated for 2026 ISP Mandates • 15 min read Executive Engineering Runbook Technical Overview & Production Verification Scope The diagnostic process for Microsoft-specific DKIM failures: The fix depends on where the long headers are being generated: If using PowerMTA: PowerMTA has header folding […]
← Back to Email Authentication Knowledge Base ⚡ Production Engineering Runbook • Updated for 2026 ISP Mandates • 15 min read Executive Engineering Runbook Technical Overview & Production Verification Scope DKIM signing algorithms are specified in the DKIM-Signature header’s a= field. Three algorithm/key-size combinations are in use in commercial email: If your DKIM public key […]
← Back to Email Authentication Knowledge Base ⚡ Production Engineering Runbook • Updated for 2026 ISP Mandates • 15 min read Executive Engineering Runbook Technical Overview & Production Verification Scope The BIMI prerequisite check: verify via the DNS record that DMARC is at enforcement and pct=100: The SVG P/S requirements that most commonly cause compliance […]
← Back to Email Authentication Knowledge Base ⚡ Production Engineering Runbook • Updated for 2026 ISP Mandates • 15 min read Executive Engineering Runbook Technical Overview & Production Verification Scope Ed25519 DKIM verification support in 2026 is broad among major ISPs but incomplete in the enterprise gateway ecosystem: Key Length 2048-bit RSA Or modern Ed25519 […]
← Back to Email Authentication Knowledge Base ⚡ Production Engineering Runbook • Updated for 2026 ISP Mandates • 15 min read Executive Engineering Runbook Technical Overview & Production Verification Scope Enforces cryptographic authentication standards across high-throughput bare-metal MTA infrastructure.: Enforces cryptographic authentication standards across high-throughput bare-metal MTA infrastructure. Eliminates spoofing and delivers mathematical alignment across […]
← Back to Email Authentication Knowledge Base ⚡ Production Engineering Runbook • Updated for 2026 ISP Mandates • 15 min read Executive Engineering Runbook Technical Overview & Production Verification Scope ARC adds three headers at each forwarding hop, all indexed with an instance number (i=1, i=2, etc.). The instance number increments at each hop, allowing […]
← Back to Email Authentication Knowledge Base ⚡ Production Engineering Runbook • Updated for 2026 ISP Mandates • 15 min read Executive Engineering Runbook Technical Overview & Production Verification Scope Email forwarding usually changes something in the signed content. The most common changes that break DKIM during forwarding: When an email passes through an ARC-capable […]