Configuring the DHCP Relay Option 60 Attribute for Traffic Forwarding

You use the DHCP relay option 60 feature to specify the action performed on DHCP client traffic. The DHCP relay uses the option 60 string in the client traffic to determine what action to take with the incoming traffic.

The following procedure describes a sample procedure that creates three actions for incoming DHCP client traffic, depending on the traffic’s option 60 string.

1. Enable the DHCP relay. Do not specify an IP address when you configure DHCP relay to support vendor-option strings.
   host1(config)#set dhcp relay
2. Configure the action DHCP relay takes when the incoming traffic has an exact option 60 string of myword. DHCP relay forwards this traffic to the DHCP server with an IP address of 192.168.7.7.
   host1(config)#set dhcp vendor-option equals myword relay 192.168.7.7
3. Configure the action DHCP relay takes when the incoming traffic has a partial match, from left-to-right, with an option 60 string you have configured. For this command, matching strings include a, ab, abc, and abcd. DHCP relay forwards matching traffic to the DHCP server with IP address 192.168.15.2.
   host1(config)#set dhcp vendor-option starts-with abcd relay 192.168.15.2
4. Configure the default option 60 action. DHCP relay takes this action when the incoming traffic has an option 60 string that does not match any of the option 60 strings that you have configured. In this example, the traffic is sent to the DHCP local server.
   host1(config)#set dhcp vendor-option default local-server
5. (Optional) View your DHCP relay vendor-option configuration.

   host1(config)#run show dhcp vendor-option
   Codes:
    *       - the configured vendor-string is an exact-match
    default - all DHCP client packets not matching a configured vendor-string
    implied - the DHCP application is configured but has not been enabled
              with the vendor-option command
    drop    - the DHCP application responsible for the action has not been
              configured yet therefore all packets for this application
              will be dropped
    Total 3 entries.
            Vendor-option                            Action              
   -------------------------------- ----------------------------------------
   abcd                             relay to 192.168.15.2 (rx: 0)               
   default(*)                       local-server (rx: 0, no-match: 0)   
   myword(*)                        relay to 192.168.7.7 (rx: 0)