Concept Guide

ip route-import 1:1 map1
ip route-export 2:2 map2
!
ip vrf VRF_2
ip route-import 2:2
ip route-export 1:1
!
!
route-map map1 permit 10
match ip address ip1
!
route-map map2 permit 20
match ip address ip2
!
ip prefix-list ip1
seq 5 permit 20.0.0.0/24 <----- This is needed for data forwarding
seq 10 permit 20.0.0.2/32 <---- This is specific to internal operation of DHCP relay
!
ip prefix-list ip2
seq 5 permit 10.0.0.0/24
Non-default VRF conguration for DHCPv6 helper
address
The ipv6 helper-address command is enhanced to provide support for conguring VRF for DHCPv6 relay helper address. To
forward DHCP packets between DHCP client and server if they are from dierent VRFs, you should congure route leak using route map
between the VRFs. For more information on conguring route leak across VRF, see
DHCP Relay when DHCP Server and Client are in
Dierent VRFs.
NOTE
:
For DHCP relay source IPv4 or IPv6 conguration to work in non-default VRF, you must enable VPN in DHCP information option.
• Specify the helper-address and VRF name (optional) to forward the DHCPv6 relay packets from client and server.
INTERFACE mode
ipv6 helper-address [vrf vrf-name] ipv6-address
Conguring DHCP relay source interface
The following section explains how to congure global and interface level DHCP relay source IPv4 or IPv6 conguration to forward all the
DHCP packets from the DHCP client to DHCP server through the congured source interface. This feature is applicable only for L3
interface with relay conguration and L3 DHCP snooping enabled VLANs.
Global DHCP relay source IPv4 or IPv6 conguration
You can congure global DHCP relay source IPv4 or IPv6 conguration using the command {ip | ipv6} dhcp-relay source-
interface
interface command in the CONFIGURATION mode. DHCP relay uses the IPv4 or IPv6 global source address of the
congured interface for relaying packets to the DHCP server. For example, if you congure DHCP relay source interface as a loopback
interface, the DHCP relay uses the congured loopback interface to forward the packets to the DHCP server using the congured IPv4 or
IPv6 address. The source interface can be a VLAN, LAG, physical and loopback interfaces.
• Specify the type of an interface and interface-number that should be used as a DHCP relay source interface.
CONFIGURATION mode
{ip | ipv6} dhcp relay source-interface interface
306
Dynamic Host Conguration Protocol (DHCP)