Route your Mailcow (dockerized) server's outbound mail to the MailGuard smarthost, and have it delivered — DKIM-signed — from reputation-managed IP pools. Your inbound mail is cleaned of spam and viruses too.
Mailcow is a modern, Postfix-based mail server suite that usually sends from a single VPS IP. Mail sent from a new or low-reputation IP can be flagged as spam by the major providers. When you configure MailGuard as your smarthost, outbound mail is signed, inspected, and delivered from reputation-managed pools.
For detailed, copy-paste configuration, see the docs. To test your domain, use the SPF/DKIM/DMARC tool and mail test.
| MailGuard | Direct from server | Doing nothing | |
|---|---|---|---|
| DKIM signature on outbound mail | Automatic (MailGuard signs) | You have to set it up | None |
| IP reputation management | Fixed, monitored pool per domain | Single IP — everyone shares the same risk | None |
| Inbound spam / virus filtering | Yes (MX redirection) | Depends on the server | None |
| Risk of blacklisting | Minimal (isolated pool) | High | High |
| Delivery visibility / logs | Real-time dashboard + API | Limited | None |
The SMTP configuration was simple and clear. We've been using it without a hitch since day one.
Together with SPF, DKIM, and the other settings, our delivery performance improved noticeably.
Thanks to MailGuard, we almost never get “the email didn't arrive” complaints from our customers anymore.
The spam-filtering results exceeded our expectations. Unnecessary traffic dropped significantly.
A great solution I'd recommend to anyone having mail delivery problems.
Inbound spam is largely filtered out. Our teams spend much less time dealing with junk email.
Let's discuss your current setup, your volume, and your delivery issues, and put together a migration plan tailored to you.
Get a QuoteMailcow is a modern, Docker-based, easy-to-manage mail server suite. It bundles components such as Postfix, Dovecot, Rspamd, and SOGo. When you send from your own server, delivery depends on your VPS IP's reputation, reverse DNS, and SPF/DKIM/DMARC alignment. On new IPs in particular, delivery can be weak at first.
Defining a smarthost hands this responsibility off. When you add MailGuard as a relayhost from the Mailcow interface, outbound mail is signed through MailGuard, passes content/rate inspection, and is delivered from a reputation-managed IP. You're freed from the burden of tracking your own IP reputation and blacklist entries.
Thanks to sender-dependent transport, you can route on a per-domain basis and assign whichever domains you like to MailGuard. On the inbound side, an MX change adds spam/virus filtering — so your modern Mailcow infrastructure gains enterprise-grade delivery and security.
