Inside a private mail server: what actually gets installed

When sendzy provisions a server for your domain, you get a machine that exists solely to send and receive your mail. No neighbors, no shared IP reputation, no noisy hostmates. Here's what's on it.

The moving parts

• Mail transfer agent — accepts outgoing messages from your campaign, relays them to the world, and receives inbound mail for your domain.
• IMAP server — stores delivered mail in each mailbox's own folder and serves it to the inbox reader.
• SASL authentication — lets your mailboxes log in to send, and rejects everyone else from relaying.
• TLS — encrypts the connection between your mailboxes and the server, and opportunistically on outbound hops.
• Maildir storage — each mailbox is a directory on disk; mail is yours, readable, and portable.

The config that makes it behave

A default mail server install will happily relay spam for the first hour it's online. The settings that matter are few but critical: relay only for authenticated users, refuse relay from strangers, size limits so one attachment doesn't choke the queue, and SASL wired into the IMAP daemon so there's one source of truth for credentials.

That's the whole story. A handful of deliberate settings turns a fresh server into a well-behaved member of the mail network.

Per-domain identity

Each server takes the hostname of the domain it serves, so the first thing remote servers see matches the mail it carries. Combined with the DNS records that get pointed at it, your messages present a consistent identity from the very first send — which is exactly what receiving providers look for.

Why private wins for cold email

Shared platforms mix your reputation with thousands of strangers. When one of them screws up, everyone's deliverability pays. A private server flips that: your reputation is a function of your behavior alone. It's the difference between renting a cubicle in a call center and owning the phone line.

None of this is exotic. It's decades-old software, configured carefully, on a machine that only answers to you. That's the whole pitch — sendzy just makes it an API call instead of a weekend project.