Alcatel-Lucent OmniSwitch 9900 Series - DHCP Server Application Example

Configuring an Internal DHCP Server DHCP Server Application Example
OmniSwitch AOS Release 8 Network Configuration Guide December 2017 page 22-11
DHCP Server Application Example
In this application example the clients or hosts obtain their IP addresses from the internal DHCP server
configured on the OmniSwitch. DHCP clients initially have no IP address and are provided IP addresses
by the DHCP server.
The external router supports the DHCP relay functionality so that it can forward DHCP frames sent to and
from the DHCP clients and server on the OmniSwitch.
In the following diagram, the OmniSwitch is acting as a DHCP server and the external router is acting as
the DHCP relay agent. The DHCP requests from the clients (eg: 200.0.0.X) are relayed from the external
router to the OmniSwitch acting as a DHCP server. The internal DHCP server on OmniSwitch processes
the requests and leases IP addresses based on the DHCP server configuration.
1 The DHCP clients are present in the 200.0.0.X network connected to the external router and also in the
220.0.0.X network directly attached to the OmniSwitch.
2 The default dhcpd.pcy file can be used to configure the DHCP server global parameters.
3 The dhcpd.conf file defines the 200.0.0.X network and 220.0.0.X network.
4 The subnet mask and DNS server address are global declarations since they are the same for each
subnet.
5 The default router address and lease times are declared as a part of the scope since they are different for
each subnet.
6 The resulting sample code for the dhcpd.conf file is as follows:
#Global parameters
option subnet-mask 255.255.255.0;
option domain-name-servers 200.0.0.99;
subnet 200.0.0.0 netmask 255.255.255.0
{
dynamic-dhcp range 200.0.0.11 200.0.0.20
{
option routers 200.0.0.254;
option dhcp-lease-time 20000;
}
}
subnet 220.0.0.0 netmask 255.255.255.0
{
dynamic-dhcp range 220.0.0.100 220.0.0.105
{
option routers 220.0.0.254;
option dhcp-lease-time 30000;
}
}