Webmail and Groupware¶
Two different kinds of software are covered here, and the difference matters when choosing:
- Webmail (SquirrelMail, Roundcube, SnappyMail) is just a client. It's a PHP application that logs in to an existing IMAP server and sends through an existing SMTP server. It holds no mail of its own. You still run Postfix and Dovecot (or use a provider) behind it.
- Groupware suites (Zimbra, Carbonio, Kopano/Grommunio, Exchange) are the whole stack in one install: MTA, mailbox store, IMAP/POP, webmail, calendars, contacts, directory and admin console. They're far easier to stand up, but harder to run alongside anything else on the same host. They own ports 25/80/443 and bundle their own copies of everything.
- SquirrelMail covers the classic PHP webmail: architecture, install,
conf.pl, hardening, and migrating to Roundcube. - Zimbra: Architecture and Administration covers components, install prerequisites, licensing status, and day-to-day
zmprov/zmcontroladministration. - Zimbra: TLS Certificates and SNI covers commercial and Let's Encrypt certificates, per-domain certificates and SNI, and troubleshooting.
Choosing today¶
| Need | Reasonable choice |
|---|---|
| Webmail in front of an existing Postfix + Dovecot | Roundcube (actively maintained, plugin ecosystem) or SnappyMail (lightweight) |
| Existing SquirrelMail install | Keep it patched with a current snapshot only as long as you need to, then migrate to Roundcube |
| Self-hosted mail + calendar + contacts for a small organization, one box | Zimbra (community builds) or Carbonio, ideally on a dedicated VM |
| No interest in running mail at all | A hosted provider; keep only a null client for server alerts (see Relaying Outbound Mail) |