Kerio Operator v2.6.4 review: A smooth operator

IP phone setup needs improving but this low cost on-premises IP PBX delivers an impressive range of call handling features

  • Good security; Simple setup; Smart queuing features
  • Phone provisioning is a slog; You’ll have to pay for Android and iOS softphones

SMEs that want a well-featured on-premises IP PBX at a very affordable price will find Kerio's Operator software has a lot to offer. This Linux-based package is surprisingly easy to deploy and can be installed on any reasonably specified hardware platform or virtualized on a Hyper-V or VMware host.

Prices starts at 252 which includes the server license, support for 5 users and the first year maintenance contract. Annual maintenance renewals are charged at around one-third of the initial price while additional users cost 21 each.

Kerio provides free softphone apps for Windows, Mac and Linux clients but its iOS and Android apps cost 2.99 and 3.59 per user respectively. Many cloud providers and on-premises vendors such as 3CX include all softphone apps for free.

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For testing, we took the Windows Hyper-V path and had the downloaded ISO file installed on our Windows Server 2016 host and ready for action in 15 minutes. The appliance's main web interface is a tidy affair and opens with a customisable dashboard showing system health, active calls, recent call history, call queues and logs.

Users can be created manually where you assign an extension number, enter their email address and control access by adding them to a call permission group. Users can also be mapped from an Active Directory (AD) server and a useful feature is that disabling a user in AD also blocks them from using their Operator account.

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From the web console's Call Routing section, we added our VoIP Unlimited SIP trunk details and assigned extensions to each of its phone number aliases. IP phone auto-provisioning is tedious as it requires a DHCP server with option 66 set, so phones use the appliance's TFTP server to download their configuration file.

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For our Yealink T23G phones, we used their own web console to manually add the appliance's IP address and an Operator username and password. They then downloaded the Yealink profile, were assigned to the user and received a company logo for their LCD display.

Mobile users without access to a softphone can stay in touch via the Operator web portal and use it to make calls, access voice mail and create custom messages or speed dial entries. Security is tight as the appliance has its own firewall and can protect against SIP password guessing by blocking IP addresses that make too many unsuccessful login attempts.

User call handling features are extensive and there's nothing to do to set up voice mail - it's enabled by default and assigned pre-recorded answering messages and instructions, a ring timeout and a 4-digit access PIN. From the Voicemail section, you can have messages left by callers emailed to users and enable incoming and outgoing call recording.

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Call queues distribute incoming calls to logged-in users and Operator has most situations covered, as it offers six handling schemes including "round robin with memory", "random" or "the least recently called agent". Music on hold can be played and you can upload custom WAV or GSM files to Operator's audio library.

Auto Attendant scripts are a powerful feature; these allow you to create extensive menus and sub-menus of options, announcements, instructions and lists of available extensions and present them to callers. Ringing groups will cause all member phones to ring when a call comes in and you can set up conferences between Operator users and external callers.

Kerio Operator is a great choice for small businesses as it supports plenty of deployment options and doesn't ask for much in the hardware department. IP phone provisioning needs streamlining but it won't be faulted for its impressive range of VoIP features and great value.


Kerio Operator is a great choice for small businesses as it supports plenty of deployment options and doesn’t ask for much in the hardware department. IP phone provisioning needs streamlining but it won’t be faulted for its impressive range of VoIP features and great value.

Recommended hardware: Intel Core Duo 2GHz or equivalent 2GB of RAM 16GB hard disk space Ethernet card

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