Hi, Habr! I want to tell you about a rather interesting and functional replacement for MS Exchange, completely free and also with a beautiful web-muzzle. The conversation will be about Kolab - a free mail server with support for collaboration, calendars, to-do lists, WebDAV, ActiveSync synchronization and other goodies that can be used both for work and for home.

Carefully, in a post a lot of pictures ...

Kolab Groupware (Part 1 - Overview)
Kolab Groupware (Part 2 - Installation)
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What it is?

Kolab is a free mail server with a beautiful web-client, within which there is everything necessary for the user: mail with support for tags, address books, notes, calendars, to-do lists, file bins and much more ...
Users can synchronize their mail, calendar and contacts to their mobile device via ActiveSync protocol.
It is also possible to fumble individual folders of your mail, calendars and contacts to other users, and fully delegate access to your mailbox.

To administer this all there is an interface in which you can: manage users, distribution groups and public folders. You can create so-called resources, this is such a special calendar for negotiations or couriers, where you can see accessibility, and book for free time.
There is also a built-in LDAP editor with which you can allow or prohibit editing any fields, for example, a primary email field — it must be generated by itself, or you can specify it manually

What's inside?

Kolab is a combine from such well-known services such as:

• 389 Directory Server - storing information about domains, users and groups, acl and some settings are also stored here (if you wish, you can use Active Directory or OpenLDAP)
• Cyrus-imap - IMAP-server, the letters themselves are stored in its database, as well as the data of calendars, notes and other user data
• MySQL - stores the data necessary for the basic services of Kolab and Roundcube
• Postfix - MTA aka SMTP server
• Roundcube is a promising and very popular web-based email client.
• Apache - the default HTTP server (you can optionally replace it with nginx)
• Amavis with Spamassassin and ClamAV - antispam and antivirus protection

Just a few of our own services:

• kolab-saslauthd - provides authorization for postfix
• kolab-freebusy - employment daemon
• kolab-syncroton - implements the ActiveSync protocol for synchronization with devices
• iRony - implements WebDAV, CalDAV and CardDAV protocols
• wallace - scans mail for groupware content
• Chwala - file client
• + stack of roundcube plugins

What does it look like?

Well, let's go now to the review. Kolab has 2 themes by default, the first is Larry , this is a classic theme for Roundcube, the second one has appeared recently - Chamelion . It appeared literally in the latest version of Kolab 3.4 and was immediately made the default theme.
In my opinion, it is somewhat overloaded, and ordinary users perceive it harder, much like Larry.
Larry looks more stylish and beautiful.
No, Chameleon is certainly not bad either, but Larry, in my opinion, is better for now, so I will post screenshots of this theme under the spoilers.

post office

The main mail screen:



This is the procedure for writing a letter:

Contacts

The calendar

This is how the calendar looks like:




Here you can see the employment of other people, if they allowed you to do this.
You can invite other people to the events you create, and they will receive notifications from you in the mail.

Notes

To-do lists

Cases can also be assigned to other users, in which case they will receive a notification in which they will have to confirm their participation.

File cloud

At the moment it is very spatial, i.e. You can’t upload external links to downloads for folders and files, it’s also not recommended to upload large files here, but you can always save files from mail “to the cloud”, as you can access them via WebDAV.

If you need something more, you probably should look towards your ownCloud , especially since with LDAP and Roundcube you will not be difficult to integrate it into the main interface of Kolab in the latest version of Kolab added the ability to integrate the cloud into Seafile

Settings screen

The settings are quite standard for Roundcube, everyone can choose a theme that he likes more. Configure sieve-rules for incoming emails. Delegate the management of your mailbox to one of the employees, without a system administrator participating in this process. For each mailbox on whose behalf the user can write letters, a separate profile is created, which can be customized in its own way, for example: assign a sender name or change the signature.

Folders

As I said, all user data, including to-do lists and notes and calendar events, is stored in IMAP. At first glance, this is a rather strange decision, but we have a flexible mechanism for managing permissions to imap-folders. You can issue permissions to read, write, change a separate folder of your mail, for example, a separate calendar for certain people, for example, colleagues from your department. You can, for example, if you go on vacation, completely delegate access to your account.

As soon as the user receives the rights from you, he will also need to log in to this interface and subscribe to the imap folders you have shared.

Alternate clients and sync

All this is of course very nice, but there is also a fly in the ointment:
If you connect your mailbox to a third-party email client, such as Thunderbird, you will see all these calendars folders among your regular email folders, but you cannot read them, because In the inside of these folders there will be only service files of the same calendars. As if it hints, use Roundcube as the main mail client, well, it copes well with this task. In addition, there is support for the ActiveSync protocol to synchronize it all to a mobile device, ActiveSync settings are conveniently made in Roundcube:




Also, for each calendar or list of contacts, or a file dump you can get a DAV-link and use it at your discretion in compatible clients.

By the way, there is also an officially supported desktop client on qt - Kontact , it is not as beautiful as Roundcube but also quite functional:



There is also an add-on for Thunderbird , it’s by mail, it adds the ability to sync individual calendars and contact lists.

More different customers and additions to them can be found here .

Admin panel

I almost forgot to mention the admin panel. The admin has a slightly different design, but this does not make it less functional.
In the admin panel you can manage users, groups, public folders. For example, you can create a group that will be automatically populated based on information received from another LDAP server, for example AD.



Here is the procedure for adding a user:

Conclusion

This is probably all.
In the second article, read about the installation of this miracle, the initial configuration and some aspects that I encountered while working with him

Official site of the project: kolab.org