User's Manual

Chapter 13: Client IP Configuration
TR0153 Rev. E1 106
13.2.3 Configuring the Central DHCP Server
Guidelines for configuring the central DHCP server are provided below. The full configuration
of the central DHCP server will depend on the type of DHCP server that is used and is beyond
the scope of this document.
Typically the following information must be available in order to configure the server:
1. The local interface (to the DHCP server) over which the DHCP-related messages from
the mesh neighborhood arrive
2. The parameter(s) that define the address lease time
3. Whether DNS and domain names are to be provided by the DHCP server to client
devices
4. The range of the flat IP address that is used for assigning IP addresses to client
devices. The range must not include the IP addresses set aside for the client access
interfaces on each mesh device.
The following is a segment of the dhcpd.conf file for a Linux DHCP server (ISC DHCP server)
that illustrates the scope settings for the mesh network:
subnet 192.168.5.0 netmask 255.255.255.0
{
option broadcast-address 192.168.5.255;
option subnet-mask 255.255.255.0;
option domain-name "domain.com";
range 192.168.5.18 192.168.5.254;
}
Note that in this definition no “routers” option is needed. If a global “routers” option is defined,
the EnRoute500s in a mesh neighborhood will automatically change it to an appropriate value
in DHCP responses to clients based on the centralized DHCP server settings on the
EnRoute500s. In this example, the mesh network includes 3 mesh devices, 2 IP addresses are
set aside for the DHCP server and the mesh gateway, and therefore the address pool starts
from 192.168.5.18.