deliverlensEmail foundations
Read an email authentication header
Find the receiver’s SPF, DKIM, and DMARC observations and keep the three identities separate.
2 min read
The Deliverlens academy
Good email starts with understanding.
Less guesswork. More useful evidence. Learn how email authentication, reputation and receiving systems fit together—one practical question at a time.
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Email foundations10 lessons available SPF, without the guesswork10 lessons available DKIM & message integrity10 lessons available DMARC & domain protection10 lessons available BIMI & brand indicators10 lessons available Email verification10 lessons available Lists that people want10 lessons available Reputation & blocklists10 lessons available Inbox placement10 lessons available Deliverability operations10 lessons available
A little clarity, on demand.
100 published lessons found.
Email foundations
Delivery vs. deliverability: know what was measured
Separate server acceptance, inbox observation, and audience engagement in a diagnostic report.
2 min read
Email foundations
Map the journey of a transactional email
Trace application, sending service, DNS, receiving server, and mailbox filtering boundaries.
2 min read
Email foundations
Run your first controlled message test
Choose one sender and one message, capture a baseline, and record repeatable evidence.
2 min read
Email foundations
Read an SMTP bounce without guessing
Extract the responding server, enhanced status, and recommended next investigation.
2 min read
Email foundations
Find the actual sending IP in a message
Identify trusted receiver evidence and avoid confusing a relay with the original source.
2 min read
Email foundations
Understand From, Return-Path, and Reply-To
Document which address serves which purpose before changing authentication settings.
2 min read
Email foundations
Check DNS changes with dig
Query the exact record name and compare authoritative and recursive answers.
2 min read
Email foundations
Choose the next fix from a diagnostic report
Prioritize reproducible authentication failures before speculative content edits.
2 min read
Email foundations
Build a sender inventory before touching DNS
Record every legitimate service, owner, domain, selector, and business use.
2 min read
SPF, without the guesswork
Check an SPF record safely
Inspect the exact sender identity and review one policy without overwriting legitimate senders.
2 min read
SPF, without the guesswork
Fix multiple SPF records at one DNS name
Consolidate authorized sources into one reviewed policy and preserve unrelated TXT records.
2 min read
SPF, without the guesswork
Investigate the SPF DNS lookup limit
Trace lookup-causing terms and dependencies rather than counting all DNS queries equally.
2 min read
SPF, without the guesswork
Understand include vs. redirect in SPF
Compare authorization composition with policy delegation using a worked DNS example.
2 min read
SPF, without the guesswork
Choose between softfail and fail deliberately
Review the meaning and operational tradeoffs of the final all mechanism.
2 min read
SPF, without the guesswork
Authorize a new email service without breaking the old one
Plan a provider change with an inventory, DNS review, and fresh message tests.
2 min read
SPF, without the guesswork
Why forwarding can change an SPF result
Follow the connecting-IP change and distinguish it from DKIM and DMARC outcomes.
2 min read
SPF, without the guesswork
Remove an obsolete SPF include
Verify that a retired sender is unused and measure the effect before deleting authorization.
2 min read
SPF, without the guesswork
Plan a custom return-path domain
Check provider support and the relationship between envelope identity and alignment.
2 min read
SPF, without the guesswork
Document SPF maintenance for your team
Assign ownership and a review checklist for future sending-service changes.
2 min read