Build a sender reputation baseline
Record the domains, IPs, PTR names, provider dashboards, blocklist status, authentication posture, and recent volume before changing anything. Recovery gets much easier when the baseline is explicit.
Reputation
Reputation & infrastructure
DNSBLs, Postmaster Tools, IP warming, PTR records and everything that shapes how receivers see you.
How to use this topic
Start with the pillar guide for the full model, follow the diagnostic workflow for the current problem, and use the commercial destination when the evidence needs to become a repeatable team process.
Monitor sender domainsTrack authentication, DNS, transport, blocklist, and provider evidence as infrastructure changes.
Curated guide
Treat blocklists as evidence, not the whole story
Some DNSBLs matter more than others, and delisting rarely fixes the root cause by itself. Connect listings to complaints, bounce patterns, list sources, infrastructure changes, and provider-specific dashboards.
Warm and separate streams deliberately
Reputation is easier to protect when transactional, marketing, and cold outreach streams have clear domains, controlled volume ramps, and monitoring that catches drift before it becomes filtering.
Diagnostic workflow
- Step 1
Establish the baseline
Record DNS, PTR, authentication, provider dashboards, and recent sending behavior.
Open workflow - Step 2
Find the failure class
Separate blocklist events, configuration drift, volume changes, and recipient complaints.
Open workflow - Step 3
Recover with controlled sends
Change one variable at a time and compare provider-specific evidence.
Open workflow
Relevant free tools
- MX lookup
Inspect mail routing and provider infrastructure.
- MTA-STS checker
Validate transport-policy publication and HTTPS policy retrieval.
Pillar guide
IP warming schedule: ramp volume with provider evidence
·4 min read
Plan gradual sending increases with reputation, complaint, authentication, placement, and list-quality evidence instead of fixed-volume folklore.
Read pillarSupporting guides
- ·10 min read
Email Throttling: Mailbox Provider Rate Limits and How to Pace Sends
Email throttling best practices: why providers return 421/452 deferrals, per-IP and per-domain limits, exponential backoff, and warmup pacing schedules.
Read - ·10 min read
Dedicated IP vs Shared IP for Email: When to Switch (and When Not To)
Dedicated IP vs shared IP for email: who should switch, the real warmup burden, volume thresholds, cost math, and when dedicated actively hurts you.
Read - ·10 min read
Why Corporate Domains Eat Your Emails: Proofpoint, Mimecast, and the SEG
Why emails get blocked by Proofpoint and Mimecast: how secure email gateways inspect, rewrite, and quarantine B2B mail — and how senders get through.
Read - ·10 min read
Inbox Placement vs Delivery Rate: Why 98% 'Delivered' Lies to You
Email delivery vs deliverability explained: why a 98% delivery rate can hide 30% spam placement, and how to measure inbox placement properly.
Read - ·9 min read
Domain Reputation vs IP Reputation: What Actually Matters in 2026
Domain reputation vs IP reputation in 2026: which one mailbox providers actually filter on, when a dedicated IP is worth it, and how to monitor both.
Read - ·13 min read
Microsoft SNDS monitor guide for Outlook sender reputation
Use Microsoft SNDS to interpret Outlook complaint, trap-hit, filter, HELO, and IP reputation evidence before sender issues become blocks.
Read - ·14 min read
PTR records and reverse DNS for email: setup and checks
Configure forward-confirmed reverse DNS, align HELO with the PTR hostname, and diagnose the infrastructure evidence receivers inspect.
Read - ·14 min read
Google Postmaster Tools guide: setup, metrics, and fixes
Set up Google Postmaster Tools, interpret reputation and compliance data, and connect each dashboard signal to a defensible next step.
Read - ·11 min read
Email subdomain strategy for safer sending
Splitting transactional, marketing, and corporate mail across subdomains protects your most important traffic from your noisiest. Here is the layout that works.
Read - ·5 min read
Blacklist removal playbook for email senders
Which DNSBLs actually matter, how to find your listings, and the exact delisting process for the eight most consequential blocklists.
Read
Frequently asked questions
- Is sender reputation one global score?
- No. Mailbox providers maintain their own signals, and domain, IP, stream, and recipient history can behave differently.
- Does leaving a blocklist immediately restore delivery?
- Not necessarily. Correct the underlying cause, verify delisting, and allow provider reputation signals to recover over time.