First introduction to mailservers


One of our major decisions will be the choice of a system to run email services for our customers. In this article, we give you some basic information about the products we are currently testing – IceWarp, MailEnable and Kerio Connect.

This article provides only a brief introduction and a statement of what each product can do. In future articles, we will provide more detailed analysis, performance test results, etc.

When researching these products, apart from the usual things (like the fact that it can receive emails), we also looked at e.g. On:

  • presence of an API interface – for the possibility of automating certain tasks by calling commands from our information and ordering systems
  • the friendliness and functionality of the WebMail interface that our customers will be working with
  • clustering option – operation of one e-mail system on multiple physical servers with mutual substitution in case of failure (fail-over cluster)
  • configurability of various things (antivirus, antispam, etc.) for individual domains and mailboxes


The IceWarp mailserver from the Czech company IceWarp software has been in development for 10 years and is used on more than 50,000 live servers serving approximately 50,000,000 users. This is a product that targets ISP companies like us in particular. The mailserver supports the classic SMTP, POP/IMAP standards, which it encrypts with all other services using SSL/TSL. Once installed, from a user perspective, there is a program administration interface, a web administration interface and a web-based mail client. Web services run on their own server. Despite the very large number of functions offered by the server, the administration interface is clear and ergonomic. Other specifics of the application are listed below.

  • Smart Attachments – Attachments do not need to be physically attached to the report. The system only saves it locally on the server and inserts a unique download link in the email. This significantly saves server traffic not only on its own server but also on the recipient’s server.
  • 24/7 Operation – ready – Monitoring of the server and its own services, which automatically notifies the server administrator by e-mail, text message or IM when a problem is detected.
  • Web Instant Messaging client – After logging into the web-based mailbox interface, users can instantly communicate or send files to each other without any configuration. The communication history is stored on the server side, so it can be accessed at any time from other IM clients. The Instant Messaging server can be connected to other IM or community networks (ICQ, MSN, Google talk!, Yahoo, AOL or Facebook).
  • Web VOIP Client – Brings users the ability to communicate by voice without the need to install a hardware or software SIP device. For connection, a java applet is used, which can also be used outside the integrated SIP server. The integrated SIP server does not only have to be used for voice transmission, but can also be used for video conferencing for two or more accounts. For these purposes, however, it is necessary to have an external SIP client installed.
  • Clustering support (but we are not clear about fail-over functionality, we will check)
  • Full Active Directory and LDAP synchronization
  • SMS Server
  • Spam filter and antivirus
  • Calendars, Contacts, Tasks, Journals (FreeBusy, iMIP)
  • Sharing emails between users within set permissions
  • Multiplatform architecture
  • Mobile synchronization (ActiveSync, SyncML)
  • Custom web interface of the mail client with its own WWW server
  • Czech + 20 other world languages
  • Very good API to configure all server services
  • Robustness of the solution


It comes from the Australian company MailEnable Pty. Ltd., which has been operating on the market since 2001. The mailserver has again a very nicely designed administration interface. The web client for accessing mail is more user-friendly and clearer than IceWarp. The disadvantage, however, is that MailEnable is bound to the Windows platform and its IIS server, without which it is not possible to access mail or web administration via the browser.

  • Advertising and Campaign Management – The MailEnable web client allows administrators to set up advertising within their website clients or globally across the entire server. Ads can be sorted into logical groups (campaigns), banner rotation can be controlled and “click” statistics can be created.
  • Cluster Management – Allows you to configure the mailserver to run on multiple computers connected to a cluster. Which is advantageous both for load distribution and redundancy in case of a server crash
  • Publishing files from web storage – All files uploaded/received on the mailserver can be easily published via a unique url and shared.
  • Active Directory and LDAP synchronization
  • SMS Server
  • Spam filter and antivirus
  • GroupWare
  • Windows OS
  • Mobile synchronisation
  • Web interface for reading emails implemented via IIS
  • Well crafted API

The biggest minus with this product is the lack of a Czech language version. According to our research, there are some unofficial procedures and modifications that can be used to make the interface easier to understand, but we have not been able to do so. Apparently other languages are not officially supported.

Kerio Connect

Founded in 2001, Kerio Technologies is one of the leading manufacturers of Internet security software for small and medium-sized networks, specializing in network firewalls and internal corporate communications security. The Kerio Connect product was launched in 2002 under the name Kerio MailServer. Kerio Connect has the most user-friendly interface of the three products. Once installed, there is an admin console, a web administration interface and a web mail client. Despite the very decent server processing, it lacks an API interface, which is very essential for the purposes of the datacenter, where all tasks should be automated within the control application.

  • Active Directory and LDAP synchronization
  • Spam filter and antivirus
  • GroupWare
  • Multiplatform architecture
  • Mobile synchronisation
  • Custom web interface for reading emails
  • Language versions including Czech

The biggest downside of this product is the lack of an API. While we were sent a program on request that can be used via the command line to somehow administer services, the program supposedly does not perform any checks and simply executes the requested command immediately, which can lead to inconsistent product status.

We are also not clear about clustering with Kerio Connect. We did find some references to it and even some configuration file, but we didn’t understand more.