Concept Guide
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 congure the remote ID as the host name in a VLT setup, congure dierent host names on
both VLT peers. If you congure the remote ID with your own string, ensure that your strings are dierent 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 congurations 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.
CONFIGURATION mode
ipv6 dhcp snooping vlan vlan-id
Adding a Static Entry in the Binding Table
To add a static entry in the binding table, use the following command.
• Add a static entry in the binding table.
Dynamic Host
Conguration Protocol (DHCP) 321