User Manual
ADCP-75-192 • Issue D • October 2005 • Section 3: Network and System Installation and Setup
Page 3-23
2005, ADC Telecommunications, Inc.
10.2.2 Incorporating Existing LAN DHCP
Using a pre-existing LAN DHCP server is ideal when the Digivance CXD network only
contains one Hub Master node. In this configuration, there is no need for a router between the
Hub Master and the rest of the LAN, since all nodes are on the same subnet. To use this
configuration, the Hub Master DHCP must be disabled using the following steps:
• Login to Hub Master node
• Type “sudo rm /etc/init.d/dhcp3-server” and enter your login password at the prompt.
This stops the DHCP server from being run.
• Type “sudo killall dhcpd3” to stop the current service.
• Type “sudo reboot” to reboot the machine.
As the Hub Master is not configured to be a DHCP client, it requires a static IP that must be
outside the range of the existing LAN DHCP. This may mean narrowing the existing DHCP
server’s address range. For example, take the case where the original DHCP range is
172.20.88.3 through 172.20.88.254 inclusive, and assume it assigns these addresses from the
upper limit towards the lower. Also assume that there’s a router at 172.20.88.1 and another
static IP device at 172.20.88.2. The Hub Master needs a static IP, but the DHCP is serving all
the “free” addresses in that subnet. To avoid DHCP collisions and the perturbation of
preexisting addresses, the operator would increase the DHCP server’s lower address limit from
172.20.88.3 to 172.20.88.4, and set the Hub Master to be IP 172.20.88.3.
It is also important to have a mechanism in place to update the LAN DNS with the Hub Master
IP address, so that the Digivance CXD nodes know where to send data. Since the Hub Master
IP is static, this can be manually entered at installation time.
The setup becomes more complicated when multiple subnets are introduced. However, it is
recommended that in such a case the Hub Master DHCP server be utilized instead.
10.2.3 Using Domain Name Service With Digivance CXD
The DNS offers a way to represent nodes using hostnames instead of IP addresses. This is an
important relationship when using DHCP, since the hostnames are more likely to be static than
their associated IP addresses. The Digivance CXD Hub Master node comes standard with a
DNS which services its related subnet. In addition, the Hub Master node can employ DNS
forwarding to utilize a pre-existing LAN DNS. The following sections outline the steps
necessary to use the Digivance CXD DNS.
10.2.4 Using The Hub Master DNS
The Digivance CXD DNS is automatically updated via NIPR/S as outlined in Section 9.2, so
there is no need to manually configure it. As this process does not interfere with existing
upstream DNS activities, it need not be disabled.