Mail-in-a-Box: a mail server in a box
Self-hosted email remains viable but contentious: users of Mail-in-a-Box and similar systems report years of stable, low-maintenance operation, yet many warn that deliverability to major providers—especially Microsoft and, less often, Gmail—can be fragile and hard to debug. Commenters outline best practices like proper DNS, SPF, DKIM, PTR records, checking blocklists, and sometimes using a trusted relay (e.g., SES, MailChannels) for outbound mail while keeping inbound fully self-hosted. Alternatives such as Mailcow, Mailu, Maddy, and commercial services like Fastmail or ProtonMail are frequently cited, and the broader theme is a trade-off between control, privacy, and decentralization on one side and reliability and convenience on the other.
Deliverability & “Is the game lost?”
- Strong disagreement on whether self-hosted mail can reliably reach big providers.
- Some report years or decades of trouble‑free delivery (including to Gmail) with correct SPF/DKIM/PTR, static IPs, and no spam.
- Others report accepted messages that disappear (especially with Microsoft 365/Outlook Enterprise) or chronic spam-folder issues from VPS IP ranges (DigitalOcean/Linode).
- IP reputation and blocklists are recurring pain points; residential IPs and some VPS netblocks are often pre‑blocked, and certain blocklists are viewed as pay‑to‑delist.
- Consensus that Microsoft/Outlook is the hardest target; Gmail is seen as mostly workable but opaque when problems occur.
Using Relays / Smarthosts
- Popular strategy: self‑host inbound mail and use reputable relays (MailChannels, AWS SES, Mailgun, others) for outbound to avoid IP reputation battles.
- This preserves control over storage, logging, and spam filtering while outsourcing deliverability.
- Some see this as a pragmatic middle ground; others question why bother self‑hosting if outbound depends on third parties.
Mail-in-a-Box Experiences
- Many report MIAB running for years on low‑cost VPSes with minimal maintenance and good deliverability, especially for personal/low‑volume use.
- Built‑in DNS, SPF/DKIM, DNSSEC, DANE, MTA‑STS, backups, and simple setup are praised.
- Major OS/MIAB upgrades are widely seen as the main weakness: disruptive, stressful, sometimes resulting in broken installs and requiring fresh servers.
- MIAB’s “not NSA‑proof” stance is appreciated as honest; it’s aimed at practical self‑hosting, not resisting state actors.
Alternatives & Architectures
- Alternatives mentioned: docker‑mailserver, Mailu, Mailcow, Maddy, Stalwart, Modoboa, iRedMail, ISPConfig, NixOS-based setups, and various groupware stacks.
- Some prefer integrated, single‑binary systems (e.g., Maddy, Stalwart + Rspamd, JMAP support) over MIAB’s multiple‑component “hodgepodge.”
- Docker‑based solutions get praise for easier upgrades; some criticize older tools that are hard to update.
Motivations, Risks, and Philosophy
- Motivations: control over spam filtering and retention, avoiding silent drops/lockouts by big providers, learning, and supporting decentralization of email.
- Risks highlighted: lost business opportunities if important mail is spam‑filtered, opaque big‑provider behavior, and upgrade‑time data loss anxiety.
- Several suggest starting with self‑hosted inbound plus aliases and gradually expanding, while maintaining backup communication channels.