Why your email lands in spam (and what it says about your host).

It is one of the more demoralising support tickets to write. The password-reset mail a customer swears never arrived. The outreach that lands in spam despite an SPF record you triple-checked and content that could pass a compliance review. You debug the message for a day. The message was never the problem. The receiving server made half its decision before it read a single word, and that half was about infrastructure: yours, and your host's.

How receivers actually score you

When a server connects to deliver mail, the receiver checks whether the connecting IP has a reverse-DNS name at all, whether that name resolves forward to the same IP (forward-confirmed reverse DNS), and whether it matches what the sending server announced as its HELO name. It weighs what this IP has sent in the past. It weighs the reputation of the surrounding range. Only after all of that does it start scoring your subject line and your content. Mail from an IP with no PTR, a mismatched PTR, or a bad neighbourhood begins the conversation as a suspect.

Rows one to three are infrastructure. Two of them belong to your host, not to you.

The half you inherit

Start with the half you did not build. First, whose space it is: our customers send from IPv4 space we hold directly from RIPE, so the range's history is ours to own and its reputation does not change hands upstream when a carrier relationship shifts. You can confirm the holder on the public registry. Second, whether anyone polices the street: on our network, outbound spam from a compromised site is caught and stopped at our edge before the upstream blocklists notice, and repeat offenders on a shared range meet real consequences with a documented release path. A range whose spammers get evicted is a range whose legitimate tenants inherit a clean score.

The half you control, in the right order

Authentication built on top of broken reverse DNS is a suit on a suspect.

“Receivers don't score your IP in isolation. They score the street it lives on, and your host is the landlord.”

What the paperwork says about the host

Here is the wider point, the one worth taking to every host you evaluate. DNS that agrees with itself, ranges that get policed, address space held in the provider's own name: none of it is glamorous, all of it is checkable, and it correlates with everything you cannot check from the outside. A host that cannot keep reverse-DNS records coherent is telling you how the rest of the network is run. Deliverability trouble is often the first visible symptom of a network run loosely. Treat it as the free audit it is.