Suppressing DHCP Routes
During the DHCP client binding operation, the DHCP process adds route information for the DHCP sessions by default. However, you can override the default behavior and prevent DHCP from automatically installing the route information. For more information, read this topic.
Suppressing DHCP Access, Access-Internal, and Destination Routes
During the DHCP client binding operation, the DHCP process adds route information for the DHCP sessions by default. The DHCP process adds the following routes:
DHCPv4 sessions—access-internal and destination routes.
DHCPv6 sessions—access-internal and access routes.
An access route represents a network behind an attached video services router, and is set to a preference of 13.
An access internal route is a /32 route that represents a directly attached end user, and is set to a preference of 12.
These routes are used by the DHCP application on a video services router to represent either the end users or the networks behind the attached video services router.
In some scenarios, you might want to override the default behavior and prevent DHCP from automatically installing the route information.
For example, DHCP relay installs destination (host) routes by default—this action is required in certain configurations to enable address renewals from the DHCP server to work properly. However, the default installation of destination routes might cause a conflict when you configure DHCP relay with static subscriber interfaces.
To avoid such configuration conflicts you can override the default behavior and prevent DHCP relay from installing the routes.
Preventing DHCP from Installing Access, Access-Internal, and Destination Routes by Default
You can use the route suppression option to override the default route installation behavior. You can configure route suppression and prevent DHCP from installing specific types of routes for:
DHCP local server and DHCP relay agent
DHCPv4 and DHCPv6 sessions
Globally or for named interface groups
For DHCPv4 you can override the installation of destination routes only or access-internal routes (the access-internal option prevents installation of both destination and access-internal routes). For DHCPv6 you can specify access routes, access-internal routes, or both.
Example:
For DHCP local server route suppression (for example, a global configuration):
[edit system services dhcp-local-server] user@host# set route-suppression access-internal
For DHCP relay (for example, a group-specific configuration):
[edit forwarding-options dhcp-relay group southeast] user@host# set route-suppression destination
For DHCPv6 local server (for example, a group-specific configuration):
[edit system services dhcp-local-server group southern3] user@host# set dhcpv6 route-suppression access access-internal
For DHCPv6 relay (for example, a global configuration):
[edit forwarding-options dhcp-relay] user@host# set dhcpv6 route-suppression access
Note the following while configuring route suppression option:
You cannot suppress access-internal routes when the subscriber is configured with both IA_NA and IA_PD addresses over IP demux interfaces—the IA_PD route relies on the IA_NA route for next hop connectivity.
The
no-arpstatement supported in legacy DHCP is replaced by theroute-suppressionstatement.