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Cisco Broadband Cable Command Reference Guide
OL-1581-08
Chapter 2 Cisco CMTS Configuration Commands
cable dhcp-giaddr
cable dhcp-giaddr
To modify the GIADDR field of DHCPDISCOVER and DHCPREQUEST packets with a Relay IP address
before they are forwarded to the DHCP server, use the
cable dhcp-giaddr
command in cable interface or
subinterface configuration mode. To set the GIADDR field to its default, use the
no
form of this
command.
cable dhcp-giaddr
{
policy
[
strict
] |
primary
}
no
cable dhcp-giaddr
Syntax Description
Defaults
No default behaviors or values
Command Modes
Interface configuration and subinterface configuration (cable interface only)
Command History
policy
Selects the control policy, so the primary address is used for CMs and
the secondary addresses are used for hosts and other customer
premises equipment (CPE) devices. This setting is typically used
when the CMs on the interface are configured for routing mode, so
that the CMs and hosts can use IP addresses on different subnets.
strict
(Optional, only when the
policy
keyword is specified) Uses the
GIADDR IP address as the source IP address in the forwarded DHCP
OFFER packet.
By default when using the
policy
option, the Cisco CMTS changes
the source IP address in the DHCPOFFER packet to match that of the
primary address on the cable interface. Use the
strict
option to
prevent this behavior, which could interfere with any access lists
applied to the CM when the CM is using a different subnet from the
cable interface’s primary address space.
primary
Always selects the primary address to be used for the GIADDR field
for both CMs and CPE devices. This option is typically used for the
Cisco uBR-MC16E card and Cisco uBR7100E series routers to
support EuroDOCSIS operations.
Release
Modification
12.0(4)T
This command was introduced.
12.0 (6) SC
This command was supported.
12.1(2) EC1
This command was supported.
12.1(3a)EC
The subinterface support was added.
12.2(15)BC2 Support for the
strict
option was added.