Administrator Guide

DHCP Snooping for a Multi-Tenant Host
You can congure the DHCP snooping feature such that multiple IP addresses are expected for the same MAC address. You can use the
ip dhcp snooping command multiple times to map the same MAC address with dierent IP addresses. This conguration is also used
for dynamic ARP inspection (DAI) and source address validation (SAV). The DAI and SAV tables reect the same entries in the DHCP
snooping binding table.
NOTE: If you enable DHCP Option 82 using the ip dhcp relay command, by default, the remote-ID eld contains the MAC
address of the relay agent. If you congure the remote ID as the host name in a VLT setup, congure dierent host names on
both VLT peers. If you congure the remote ID with your own string, ensure that your strings are dierent on both VLT peers.
DHCP Snooping in a VLT Setup
In a VLT setup, the DHCP snooping binding table synchronizes between the VLT nodes. Similarly, the DAI and SAV tables also synchronize
between VLT nodes. For this feature to work in a VLT setup, make sure that DHCP relay, DHCP snooping, SAV, and DAI congurations are
identical between the VLT peer nodes.
Enabling DHCP Snooping
To enable DHCP snooping, use the following commands.
1 Enable DHCP snooping globally.
CONFIGURATION mode
ip dhcp snooping
2 Specify ports connected to DHCP servers as trusted.
INTERFACE mode
INTERFACE PORT EXTENDER mode
ip dhcp snooping trust
3 Enable DHCP snooping on a VLAN.
CONFIGURATION mode
ip dhcp snooping vlan name
Enabling IPv6 DHCP Snooping
To enable IPv6 DHCP snooping, use the following commands.
1 Enable IPv6 DHCP snooping globally.
CONFIGURATION mode
ipv6 dhcp snooping
2 Specify ports connected to IPv6 DHCP servers as trusted.
INTERFACE mode
ipv6 dhcp snooping trust
3 Enable IPv6 DHCP snooping on a VLAN or range of VLANs.
Dynamic Host
Conguration Protocol (DHCP) 283