6.7

When the target machine first boots, it broadcasts a packet across the network requesting information to
boot itself. The DHCP server responds. The DHCP server must be able to determine whether the target
machine is allowed to boot and the location of the initial boot loader binary, typically a file on a TFTP
server.
Caution Do not set up a second DHCP server if your network already has one. If multiple DHCP servers
respond to DHCP requests, machines can obtain incorrect or conflicting IP addresses, or can fail to
receive the proper boot information. Talk to a network administrator before setting up a DHCP server. For
support on configuring DHCP, contact your DHCP server vendor.
Many DHCP servers can PXE boot hosts. If you are using a version of DHCP for Microsoft Windows, see
the DHCP server documentation to determine how to pass the next-server and filename arguments to
the target machine.
Example of Booting Using TFTP with IPv4
This example shows how to configure an ISC DHCP server to boot ESXi using a TFTP server at IPv4
address xxx.xxx.xxx.xxx.
#
# ISC DHCP server configuration file snippet. This is not a complete
# configuration file; see the ISC server documentation for details on
# how to configure the DHCP server.
#
allow booting;
allow bootp;
option client-system-arch code 93 = unsigned integer 16;
class "pxeclients" {
match if substring(option vendor-class-identifier, 0, 9) = "PXEClient";
next-server xxx.xxx.xxx.xxx;
if option client-system-arch = 00:07 or option client-system-arch = 00:09 {
filename = "mboot.efi";
} else {
filename = "pxelinux.0";
}
}
When a machine attempts to PXE boot, the DHCP server provides an IP address and the location of the
pxelinux.0 or mboot.efi binary file on the TFTP server.
Example of Booting Using TFTP with IPv6
This example shows how to configure an ISC DHCPv6 server to boot ESXi using a TFTP server at IPv6
address xxxx:xxxx:xxxx:xxxx::xxxx.
#
# ISC DHCPv6 server configuration file snippet. This is not a complete
# configuration file; see the ISC server documentation for details on
# how to configure the DHCP server.
#
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