I'm looking at the docs and it seems like you need to have a linux user on the server for every account? is this true or am I misunderstanding?
LDAP support is in the official extra modules: https://github.com/OpenSMTPD/OpenSMTPD-extras/tree/master/extras/tables
If there's something nowadays that comes all-in-one, like SMTP and POP and IMAP I want it now. I have a friend using a combination of postix+courier that I configured about 10 years ago and I need to help replace despeartely.
@mewmew No linux email server that I know of has its own webmail client. Most common and generally useful are postfix and exim, using dovecot for imap access and roundcube for webmail. If you're looking for a simple solution cPanel is great for web and email hosting, and is based on exim, dovecot, and several webmail clients including roundcube.
@mewmew I think roundcube is in PHP, so should use a basic LAMP or LEMP stack, and uses IMAP for access to the email server (hence the dovecot).
I don't know how 'good' these are to set up because I've never had to set them up myself, but they definitely don't take much room. I used to run these together with an XMPP server and other stuff, including pleroma (that at the time used about 60MB), on a 512MB SBC
@mewmew Easiest solution, however, is to get a shared hosting package at HostGator or my hosting at resplendentwebservices.com; email and webmail are already set up and easily administered via web GUIs. That is, unless you're planning to do something illicit...
postfix/dovecot for smtp & imap, spamassassin for spam, use postfixadmin for administering users and i just have squirrelmail set up in case i actually need webmail (i rarely do but boy howdy does it save the day when i DO need it). this setup is very well documented and is, all-in-all, quite hands-off once configured.
you'll have more problems with major companies thinking you're a spammer than you will with the software.