Microsoft Exchange Server has the backing of the world’s largest software provider and interoperability with a large stable of Microsoft products. The Exchange Server system isn’t free to use; however, Microsoft offers a 180-day free trial of the software.
This email server can only be installed on Windows Server, so if you are looking for an email server for a different operating system or you just want to get away from the big software houses, then Kolab is an interesting alternative.
About Kolab
Kolab leverages the procedures and protocols of email delivery to create a “collaboration suite” that includes task management, calendars, and note-taking. This is an open source project, so you can get the source code and adapt it if you have the programming resources. As a free, open source system, the standard Kolab user relies on a community forum for tips and support.
Those who want to upgrade to help desk assistance can pay Kolab Systems for a fully-supported and managed software package. The paid version is the same as standard free Kolab, but it comes with performance guarantees, security patches, and full telephone support.
Kolab Systems is based in Switzerland and offers a Cloud-based version of Kolab, which rivals the Microsoft Exchange Software as a Service (SaaS) package.
So, Kolab measures up as a viable alternative to Microsoft Exchange Server. Let’s take a look at how these two email systems compare.
Server platform
The hardware requirements for these two options immediately differentiate them. Microsoft Exchange Server can only be installed on Windows Server.
Kolab is a Linux system with versions built primarily or CentOS and RHEL. The software can also be installed on Debian, Ubuntu, SLES, Univention, OpenSUSE, and ClearOS.
Compatible clients
The Kolab Desktop Client is available for Windows as well as Ubuntu and Fedora Linux, so you don’t need to have a Linux-only environment in order to use this system. The cloud-based service is accessed through the Kolab client, so you would be able to use Kolab in your business even if you don’t have a Linux server.
Both the on-premises Kolab email server and the cloud-based version can communicate with non-Kolab email clients, including Microsoft Outlook. Other clients that work with Kolab’s server are KDE KMail and Kontact, Roundcube, Mozilla Thunderbird, and Lightning.
Microsoft Exchange Server uses a proprietary protocol to communicate with clients. This initially limited the user’s choice of email clients. The Exchange Server was designed to communicate only with Microsoft Outlook. However, over the years, Microsoft has developed more email clients and also lets other email client developers in on their communications protocols, which are called MAPI/RPC. The Linux GNOME Evolution personal information management suite can channel Microsoft Exchange and so can Hiri, an email client that installs on Windows, Mac OS, and Linux.
The implementation of Exchange Web Services as an alternative communication method to MAPI enabled Microsoft to develop Exchange-compatible clients for Macs. These are Microsoft Entourage and Microsoft Outlook for Mac. Apple’s Mail is also able to communicate with Microsoft Exchange Server now.
Microsoft extended Outlook’s platform roll call when it created Outlook Mobile Access, which creates access from Outlook apps for iOS and Android. Web platforms, including Microsoft’s own Outlook.com, extend the accessibility of Microsoft Exchange.
The addition of open email protocols has expanded the client options open to businesses that use Microsoft Exchange. Mozilla Thunderbird and Lotus Notes can act as clients to Microsoft Exchange Server via the POP3 and IMAP4 protocols, which are now built into Microsoft Exchange.
Both Microsoft Exchange Server and Kolab can communicate with the Simple Mail Transfer Protocol (SMTP), the Post Office Protocol (POP3), the Internet Message Access Protocol (IMAP), and ActiveSync.
Cloud-based email server
Many independent cloud service providers offer Microsoft Exchange servers bundled in with their other services. Exchange email is often included with Web hosting services and Microsoft also now provides its own cloud-based managed Exchange Server on monthly subscription plans. The Microsoft Exchange Online plans are charged annually on a per-user basis.
The basic Online plan includes 50 GB of storage. Higher plans include unlimited storage and also process voicemail. The top plan offered as a cloud service package by Microsoft bundles in all of the Microsoft Office suite that can be accessed by employees online. This package also includes video conferencing features.
Kolab Now is the cloud offering of Kolab Systems that adds commercial services on top of the free, open-source Kolab Mail Server. Kolab Now isn’t free and its basic package is more expensive than Microsoft’s entry-level offer. The Kolab Now pricing structure offers individual accounts or group accounts. The pricing for the group account is not as transparent as the Microsoft tariff and it is scalable depending on the number of users and the amount of storage space the buyer specifies.
Kolab Now offers a 30-day free trial for both of its plans. Microsoft doesn’t offer any free trial for its Exchange Online plans. However, the top plan for Microsoft Exchange Online is actually part of the Office 365 Business Premium package and that can be had on a 30-day free trial.
Authentication methods
Kolab offers more comprehensive authentication procedures than Microsoft Exchange Server. The Kolab system requires separate authentication to the file system of the email server and its database, whereas one sign in to the administration system in Exchange gets access to all elements.
Microsoft Exchange Server’s authentication system relies on Active Directory. This is a well-established resource and user management system that is used by many applications. The heart of the system is a database that relates users to resources. AD is only available on the Windows operating system and it is the standard authentication method used for all Microsoft products, including the Windows operating system.
Kolab’s user authentication is based on LDAP. This is the Lightweight Directory Access Protocol, and it is another well-known authentication system. LDAP is not limited to Windows, and so it is available for Linux systems. LDAP is used for the Domain Name Service (DNS), so every time you access a Web page, your computer uses LDAP to get the IP address of the site that you want to visit.
Both Microsoft Exchange and Kolab employ the SMTP AUTH standard. This is an extension of the Simple Mail Transfer Protocol that specifies procedures for user access and security. When POP3 is in use, both Exchange and Kolab use the APOP capability to pre-approve users and eradicate the need for a user to log in to send each message.
Kolab Now, the online version of Kolab’s server, offers two-factor authentication for user log in as an optional extra. One problem with this feature is that it disables email synching and makes it impossible to use IMAP procedures that download messages into storage in the email client application.
Data security
Both Microsoft Exchange Server and Kolab employ data loss prevention (DLP) methods to facilitate the backup of data and keep contents and tracking information available.
Microsoft’s DLP implementation specifically complies with the regulatory standards on personally-identifiable information (PII) and the Payment Card Industry (PCI).
Exchange uses ActiveSync to make emails available anywhere. The system is able to wipe remotely stored emails and lock an individual account. These functions are specifically aimed at protecting company data in the event of loss or theft of mobile devices that have access to emails managed by Microsoft Exchange.
Mail security
The security procedures of your email system largely depend on the email client that you use and the compatibility of clients for the correspondents of all emails sent by users of your email system. End-to-end encryption, by its very definition, has to be coordinated by the clients of the sender and receiver and cannot be implemented by the server. However, the server can play a part in the protection of data between itself and its clients.
Both Kolab and Microsoft Exchange use Transport Layer Security (TLS) procedures through an SSL library to protect data in transit. In both cases, Perfect Forward Secrecy (PFS) reissues encryption negotiation with each transmission to prevent compromised keys from exposing all communications.
The cloud-based services of both systems use HTTPS to protect the uploads and downloads of data to and from the server.
Anti spam measures
Sender Policy Framework (SPF) blocks spoofing by verifying that the sending email server is actually the authorized server for the domain contained in the email address on an incoming email. This system is employed by both Microsoft Exchange and Kolab.
Both the onsite and Cloud versions of Microsoft Exchange have more comprehensive anti spam measures than their Kolab counterparts. The onsite Exchange includes antivirus protection, while the cloud-based version integrates a package of security measures, called Exchange Online Protection (EOP). Although it is cloud-based, EOP filtering can also be applied to onsite Exchange Server implementations.
EOP takes a lot of measures to protect user email clients and also the email server itself from malware attacks and hacker strategies. The system is an email filtering service that scans all incoming emails before they get to your server. The filter looks for sender identification anomalies with SPF and also tracks email abusers through a centralized blacklist. EOP will scan for malware signatures and apply customer-selected policy filtering, blocking emails from banned sources or domain names that include specified keywords.
The EOP system offers very strong protection and it can be subscribed to as a standalone service whichever email server you use, so you could employ Microsoft EOP as a front-end for your Kolab email server.
Companion applications
Kolab is billed as a collaboration system with calendar functions and contact databases that enable task scheduling and data sharing. However, the implementation of these features greatly depends on the compatibility of the email client chosen by the business to interact with the Kolab server.
The calendar can be set up with groups so a task written by one user ripples through to the calendars of associates. The Kolab system also enables file sharing. However, that feature requires file storage that integrates version control and file locking. A second, centralized calendar system enables resources, such as equipment and meeting rooms to be reserved.
Microsoft Exchange also comes with a calendar feature and contact database. These features mesh with Outlook, so if you go with the recommended combination of Exchange and Outlook, you will be able to benefit from the full scheduling and group chat features of this email server.
With Outlook as the client, each user can access the same contact list, calendar, and email Inbox across devices. The Exchange system also allows the deployment of centralized calendars for scheduling, in a similar way to the collaboration features of Kolab. Exchange also includes document tracking and version control.
The optional extras that Microsoft offers with Exchange are unbeatable. Rather than expressing its productivity suite, Office 365 as an add-on to Exchange, the company bundles Exchange Server into its Office 35 Business package. This gets you integration with Excel, Word, and the other tools included in the Office 365 suite.
Microsoft Exchange Server and Kolab comparison
A straightforward comparison between the basic versions of Microsoft Exchange and Kolab is much easier to perform. Exchange works on Windows and Kolab works on Linux.
Exchange is a paid package, whereas Kolab is free to use. Both onsite servers offer collaboration features and include similar levels of data protection and transmission security.
The online systems of the two alternative email servers have more in common than the onsite versions. Kolab offers much greater functionality in its cloud version than the basic free open source on-premises package; the cloud platform of both erases the operating system dependence that differentiates the installed versions. Another factor that brings the online version of Kolab, Kolab Now, closer to the offer of Microsoft Exchange is that it is a paid-for service.
Kolab is a great email server for the Linux environment and its adaptability to the number of email clients that it can work with means that you can even distribute Outlook to your users and gain a lot of the front-end functionality that Exchange delivers.
The free Kolab is a good option for small businesses. However, larger businesses that need guaranteed performance would need to opt for the Help Desk support package offered by Kolab Systems. Once you step up to the paid versions of Kolab, either on-premises or online, the price advantage of Kolab erodes and the performance benefits of Microsoft Exchange become more attractive.
By offering a free, open-source option, Kolab Systems has reached out to a wider market than Microsoft. However, Microsoft is still unbeatable for serving the business sector.
