Ubuntu Unleashed 2019 Edition: Covering 18.04, 18.10, 19.04

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you want a computer on your network to have a specific IP address or other
information specific to that host. The key to completing the host section is to
know the hardware address of the host. As you learned in the “Hardware
Devices for Networking” section, earlier in this chapter, the hardware address
is used to differentiate the host for configuration. You can obtain your
hardware address by using the ip command, as described previously:


Click here to view code image
host hopper {
hardware ethernet 08:00:07:26:c0:a5;
fixed-address hopper.matthewhelmke.com;
}


This example takes the host with the hardware address
08:00:07:26:c0:a5 and does a DNS lookup to assign the IP address for
hopper.matthewhelmke.com to the host.


DHCP can also define and configure booting for diskless clients, like this:


Click here to view code image
host bumblebee {
hardware ethernet 0:0:c0:5d:bd:95;
filename "vmunix.bumblebee";
server-name "kernigan.matthewhelmke.com";
}


The diskless host bumblebee gets its boot information from server
kernigan.matthewhelmke.com and uses vmunix.bumblebee
kernel. All other TCP/IP configuration can also be included.


CAUTION
Remember that, to avoid problems, only one DHCP server should be
configured on a local network. DHCP might not work correctly for you on a
LAN with hosts running outdated legacy operating systems. Often,
Windows NT servers have the Windows DHCP server installed by default.
Because there is no configuration file for NT to sort through, that DHCP
server configures your host before the Linux server if both machines are on
the same LAN. Check your NT servers for this situation and disable DHCP
on the NT server; afterward, your other DHCP-enabled hosts should
configure correctly. Also check to make sure there are no conflicts if you
use a cable or DSL modem, wireless access point (WAP), or other
intelligent router on your LAN that can provide DHCP.

Other Uses for DHCP

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