Blog.

Google Postmaster

24 min read

Google Postmaster Tools: how to set it up and read it

Which domain to add, what each of Google's eight measurements means, and the one dashboard worth checking first.

Symptom · Spam

11 min read

Why your emails are going to spam, and why most fixes don't work

Every guide gives you a checklist. None of them explain how to tell which item on it is actually your problem.

Gmail · Spam

8 min read

The 6 most common causes of Gmail spam placement, and how to diagnose each

Most spam placement traces back to one of six causes. They all look identical from the outside.

Domain Warmup

6 min read

Domain warmup: what most guides get completely wrong

A generic warmup schedule can be worse than no warmup at all. Here's why, and what to do instead.

SPF · DMARC

7 min read

Why your SPF record might be actively making things worse

Multiple SPF records, ~all vs -all, and the lookup limit that quietly kills senders who think they're fine.

Reputation

7 min read

Shared IP pools: when your reputation isn't yours

How a neighbor on the same IP block can tank your placement, and how to tell if it's happening to you.

Spam Placement

8 min read

How to stop emails going to spam, in the order I actually check

Most advice hands you twelve things to fix and never says which one is yours. This is the sequence I actually run instead.

Gmail · Postmaster

7 min read

How the Gmail spam filter actually decides where your mail goes

Google publishes a hard threshold you can measure yourself. What it doesn't publish is how the pieces interact.

DMARC · Policy

8 min read

DMARC p=reject, what it actually does and when to set it

Most of the damage from p=reject hits senders who set it correctly and had no idea what it would do to forwarded mail.

IP Warmup

6 min read

IP warmup schedule: what should actually set your ramp

Warmup works. A generic day-count schedule that ignores your list, volume and mailbox providers doesn't.

Bounce Codes

6 min read

Soft bounce vs hard bounce, and the difference that actually matters

Temporary versus permanent is the textbook answer. It hides the part worth knowing: a hard bounce doesn't reliably mean the address is bad.

Bounce · 550

3 min read

550 5.7.1: what this bounce actually means

The receiving server accepted your message and refused it for a policy reason. How I tell an authentication gap from a reputation problem.

Bounce · 550

3 min read

550 5.1.1: what this bounce actually means

The receiving server found no mailbox at that address. How I tell a genuinely dead address from a typo or a full mailbox.

Bounce · SMTP 421

3 min read

SMTP 421: what this response actually means

A 421 is the server closing the connection, not rejecting your message. How to tell a capacity blip from a reputation throttle.

Blocklist · UCEPROTECT

3 min read

UCEPROTECT: what Levels 1, 2 and 3 actually mean

UCEPROTECT runs three separate lists. Which one is blocking you decides who can actually fix it.

Blocklist · Spamhaus

3 min read

Spamhaus DBL: what actually gets a domain listed

The DBL lists domains by how they were used in mail traffic, not by who owns them.

Setup · GoDaddy

3 min read

DKIM for GoDaddy: where the record actually goes

GoDaddy hosts your DNS, not your email. Exactly where the DKIM record goes, and why most failures aren't GoDaddy's fault.

Setup · Workspace

3 min read

DKIM for Google Workspace: the actual setup steps

Generated in the Admin console, not your DNS panel. The exact steps, and why it's the first thing worth checking.

Setup · Workspace MX

3 min read

Google Workspace MX record: the exact values

One value, repeated. The exact record, and what a correct MX record doesn't fix on its own.

Glossary · DMARC

1 min read

What is DMARC?

Resolves the one thing SPF and DKIM can't decide alone: what happens after an authentication check fails.

Glossary · DKIM

1 min read

What is DKIM?

Confirms a message wasn't altered and that a domain authorized it. It doesn't check the address you actually see.

Glossary · SPF

1 min read

What is SPF in email?

Authenticates the envelope sender, not the visible From address you see in your inbox. What that distinction means.

Glossary · BIMI

1 min read

What is BIMI?

Displays your logo in a recipient's inbox, gated on DMARC enforcement you may already have. What actually unlocks it.

Setup · GoDaddy SPF

2 min read

SPF record for GoDaddy: where it goes

A TXT record like any other, but only one may exist per domain. Where it goes, and the most common way it breaks.

Setup · Workspace SPF

2 min read

Google Workspace SPF record: the exact value

One line, published at your DNS host, not the Admin console. The exact value, and where it actually goes.

Setup · Office 365

2 min read

DKIM for Office 365: the two CNAME records people miss

Microsoft 365 DKIM uses two CNAME records, not one, so it can rotate keys automatically. Missing the second is the common gap.

Blocklist · Barracuda

2 min read

Barracuda blacklist: what causes a BRBL listing

Most BRBL listings trace to bad data or a dynamic IP's history, not malicious sending. What actually causes each.

Blocklist · Spamhaus SBL

2 min read

Spamhaus SBL: how it differs from the DBL

Lists IP addresses, not domains. What actually gets an IP listed, and why it's a different problem than a DBL listing.

Bounce · DSN

2 min read

Delivery status notification failure: what it means

A DSN failure is the receiving system's own bounce report. How to read it as a sender, not just a stuck message.

Bounce · 550

2 min read

550 permanent failure: what permanent actually means

Means resending will not help, not that the problem is unfixable. Here is the difference, and how I read the code underneath it.

Bounce · 554

2 min read

554 5.7.1: what this bounce code means

The same policy refusal as 550 5.7.1, on a different base code. What the 554 specifically signals, and what doesn't change.