Version 1.0, 05/2013. Copyright 2012 Hitron Technologies
26
Version 1.0, 05/2013. Copyright 2013 Hitron Technologies
26
Hitron CDA-RES User’s Guide
2.3
DHCP
The Dynamic Host Configuration Protocol, or DHCP, defines the process by which IP
addresses can be assigned to computers and other networking devices
automatically, from another device on the network. This device is known as a DHCP
server, and provides addresses to all the DHCP client devices.
In order to receive an IP address via DHCP, a computer must first request one from
the DHCP server (this is a broadcast request, meaning that it is sent out to the whole
network, rather than just one IP address). The DHCP server hears the requests, and
responds by assigning an IP address to the computer that requested it.
If a computer is not configured to request an IP address via DHCP, you must
configure an IP address manually if you want to access other computers and devices
on the network. See
IP Address Setup
on page
17
for more information.
By default, the CDA-RES is a DHCP client on the WAN (the CATV connection). It
broadcasts an IP address over the cable network, and receives one from the service
provider. By default, the CDA-RES is a DHCP server on the LAN; it provides IP
addresses to computers on the LAN which request them.
2.4
DHCP Lease
“DHCP lease” refers to the length of time for which a DHCP server allows a DHCP
client to use an IP address. Usually, a DHCP client will request a DHCP lease
renewal before the lease time is up, and can continue to use the IP address for an
additional period. However, if the client does not request a renewal, the DHCP server
stops allowing the client to use the IP address.
This is done to prevent IP addresses from being used up by computers that no longer
require them, since the pool of available IP addresses is finite.
2.5
MAC Addresses
Every network device possesses a Media Access Control (MAC) address. This is a
unique alphanumeric code, given to the device at the factory, which in most cases
cannot be changed (although some devices are capable of “MAC spoofing”, where
they impersonate another device’s MAC address).
