Configuring Built-in DHCP server in Kerio Operator

Kerio Operator includes a built-in DHCPDynamic Host Configuration Protocol - A protocol that automatically gives IP addresses and additional configuration to hosts in a network. server. There are deployment scenarios in which it is useful to have a separate DHCP server for VoIPVoice over Internet protocol - A digital telephone system that uses the internet as the transmission medium, rather than the PSTN. devices:

  • In larger networks, you may need a LAN segment dedicated to voice traffic.
  • In smaller networks, the router/firewall sometimes does not support the DHCP option 66 for automatic provisioning of phones.


DHCP server is disabled in the default mode so that it does not collide with your existing DHCP server.

Configuring DHCP server

The built-in DHCP server must have a static IP address:

  1. In Kerio Operator administration interface, go to the Network section.
  2. Select a network interface and click Edit.
  3. In the Interface Properties dialog, switch configuration to Use the following configuration and type a new static IP address, mask and gateway.
  4. Check Enable DHCP server.
  5. Click OK to save the settings.

Kerio Operator will derive the configuration of the DHCP server from the values you set for the interface’s IP address, network mask, and gateway. The DHCP server sends option 66 to Kerio Operator’s own address with every address lease.

Assigning IP addresses

Kerio Operator generates the range of IP addresses from a configured mask of a network interface and assigns these addresses automatically.


  • The configured IP address for a network interface is
  • The configured mask is
  • The gateway has the address

In this example, the range of IP addresses is —

Example — LAN segment is dedicated to voice traffic

In our example, you have LAN and you need to add an other network interface as a special telephony segment.

DHCP is running in the particular segment —scheme

You need to configure two interfaces in Kerio Operator administration interface:

  1. Go to section Configuration > Network > General.
  2. Configure interfaces as displayed bellow.

DHCP is running in the particular segment