What solution to choose for a mail server?

Question

linux

Good afternoon! The crux of the matter is as follows. There are two cities in each will have a mail server. Let's say the manager sends a letter with an attachment of 50 mb. The letter should be sent to the local mail server and from there it should be transferred to the external mail server, because the Internet is not always fast and sometimes there is no way to wait, but for the manager it should be transparent. And rather the central server will be in another city. What can be used in this case (naturally free)? What are the general solutions? The request not to throw stones with mail never worked at all.

Answer 1

Why, no, seriously, WHY do you need your own email infrastructure? If you want everything to work and not require time for support, then connect the domain to Yandex.PDA and don't reinvent the wheel.
Well, if you need to upgrade your experience, then Postfix, OpenDKIM, spf, Dovecot and other little things will help you.
For 20+ employees, it makes sense to make an LDAP (or Windows AD) server to store all user accounts and use OpenLDAP everywhere to connect to it.
The easiest web client to use as an email client is the Roundcube web client: it is visually rather poor, but it can do a lot compared to more glamorous solutions. Well, this will ensure that there are no questions like "how can I connect Outlook to your mail?"
Mail clients on phones work without problems with any mail, as long as there is a normally configured IMAP and SMTP.

Answer 2

Option one - install and forget this Zimbra: fast practical but little experience
pros: fast and often works out of the box.
cons: if something breaks, you are unlikely to immediately figure out what is wrong.
The second option is to set it up yourself - a long time but a lot of useful experience.
pluses: a fairly complete understanding of what and how it works and trouble-free repairs, the ability to finish it to fit your needs.
cons: it takes time to study the materials and walk the rake.
The most commonly used components of free mail systems:
OS - choose from Centos or Debian, if you have a lot of time and want a bonus experience, then Gentoo.
exim or postfix - dovecot smtp server
or courier imap - pop3/imap server
The base where to store logins, passwords, etc., it can be either a text file or a MySQL or Postgres database,
then you probably want a spam filter - spamassasin, amavisd
antivirus - clamav
server side filters for mail (arrange mail into folders based on rules) sieve
webmord to access mailboxes squirremail. roundcube, horde, etc.
to the webmord for user management (if in the database) postfixadmin , something
like this.

Answer 3

Sendmail, Postfix, Exim

Answer 4

I would recommend you iRedMail - a script that will install and configure a mail server on any popular distribution, and even install a panel with domain and user management. Roundcube is also automatically installed. I've been using it on my own server for almost a year, everything works fine, except that periodically *.index files in the mail folder turn out to be broken, these are Dovecot files, they are used to speed up work, I just delete them by cron once an hour, everything works fine and without glitches. There is a web interface, anti-spam, desktop and mobile mail clients work without problems, there are mail filters on the server side. In general, I am satisfied, before that I used mail for the Yandex domain.
After installing a working system, you can configure it, but at least you will have everything working initially as a starting point.

Answer 5

Debian: exim + dovecot + MySQL + postfixadmin (Web interface). Moreover, MySQL will be on the same server (shared), and set up a bunch of two exims so that there is "replication".
PS Sendmail gurus rest on their laurels, hardly anyone will tell you (or there will be an adequate manual) how to set it up.

Answer 6

I’ll try to dissuade the option “It should be transparent for the manager,” I
explain - the manager, seeing that the letter has flown away, starts calling the addressee - check the mail, then they find out that the recipient of the letter does not have repeated sendings, etc. Following the panic with the% $ removal of techies. No explanation or explanation helps. let the managers see how the shipment is going.