Postmaster Resources

Email Deliverability & Postmaster Guides

Practical, no-nonsense guides on email authentication, deliverability, blacklists and inbox placement — written by the operations team behind a high-volume transactional mail platform.

The Complete Email Deliverability Guide for 2026

Every factor that decides whether your message lands in the inbox or the spam folder, in one comprehensive walkthrough.

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SPF, DKIM and DMARC: The Complete Authentication Stack

How the three protocols fit together, the right setup order, and how to test the whole chain end-to-end.

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What is SPF? A Beginner's Guide to Sender Policy Framework

How SPF works, the syntax of an SPF record, the most common mistakes, and how to verify yours is correct.

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How to Set Up DKIM for Your Domain (Step-by-Step)

Generate the keys, publish the DNS record, sign your mail and verify the signature is valid — in plain English.

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DMARC Explained: Protect Your Domain from Spoofing

The difference between p=none, quarantine and reject, what alignment means, and why every domain owner needs DMARC.

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How to Check If Your IP Address Is Blacklisted

The blacklists that actually matter, how to query them, and what a listing on each one means for delivery.

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Hard Bounce vs Soft Bounce: What Every Sender Must Know

Definitions, common causes, the impact on your sender reputation, and the right way to handle each type.

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How to Read DMARC Aggregate Reports (XML Explained)

The structure of a DMARC report, the key fields, what each failure means, and the best tools to parse them.

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Email Headers Explained: A Postmaster's Complete Guide

Walk through every header that matters — Received chain, DKIM-Signature, Authentication-Results and more.

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PTR Records and Reverse DNS: Why They Matter for Email

Forward-confirmed reverse DNS, how to set a PTR with your provider, and what happens when it's missing.

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How to Warm Up a New IP Address for Email Sending

Why a fresh IP needs warming, a 30-day schedule that actually works, and the metrics to monitor along the way.

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Gmail Postmaster Tools: A Practical Walkthrough

Set it up, read your reputation panels, understand the spam-rate threshold, and act on what the data tells you.

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What is a Mail Transfer Agent (MTA)?

MTA vs MUA vs MSA, how SMTP actually moves a message, and a tour of the most popular MTAs in production today.

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How to Get Removed from an Email Blacklist

Identify which list flagged you, fix the root cause first, then submit a delisting request that actually gets approved.

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Transactional vs Marketing Email: Key Differences

Definitions, the legal implications under CAN-SPAM and GDPR, infrastructure separation, and why mixing them ruins delivery.

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Mail Infrastructure
Domain postitif.com
IP Address 135.125.131.105
MX Record mail2.doposta.com (pri 10)
Operator BounceZero Ltd — bouncezero.io
Authentication Status
SPF

Sender Policy Framework configured. Only authorised IPs may send for this domain.

DKIM

All outbound messages signed with a 2048-bit RSA key. Selector published in DNS.

DMARC

Policy set to reject. Aggregate reports collected and reviewed daily by the postmaster team.

Postmaster Contact

For deliverability questions, abuse reports or feedback loops contact postmaster@bouncezero.io or abuse@bouncezero.io. Response time is typically within one business day.

BounceZero Ltd — 66 Paul Street, London EC2A 4NA, UK — Company No. 17153835

Related Mail Infrastructure Resources
delgara.com — Email Deliverability Guides doposta.com — Postmaster Guides