I have determined the interface-level "dhcp relay destination dhcp-svr " command does not forward packets from a VLAN subinterface. This is on a Netvanta 3450 router running R10.3.0.
The commands I used that are not forwarding DHCP requests:
interface eth 0/2
encapsulation 802.1q
no shutdown
!
interface eth 0/2.2
vlan-id 1235
ip address 172.30.21.1 255.255.255.0
ip dhcp relay destination 172.16.21.252
no shutdown
!
Working commands I found from the Configuring UDP Relay document:
ip forward-protocol udp bootps
interface eth 0/2
encapsulation 802.1q
no shutdown
!
interface eth 0/2.2
vlan-id 1235
ip address 172.30.21.1 255.255.255.0
ip helper-address 172.16.21.252
no shutdown
Is this a software bug?
Thank you for asking this question in the support community. I tested this on a newer AOS and it appeared to work properly. Have you had a chance to try this on a newer version of firmware (R10.3.2 or R10.5.0)?
Please, let me know the results when you get a chance to upgrade firmware and test again.
Levi
I will attempt to test in a maintenance window in the next week or so.
I went ahead and flagged this post as “Assumed Answered.” If any of the responses on this thread assisted you, please mark them as either Correct or Helpful answers with the applicable buttons. This will make them visible and help other members of the community find solutions more easily. If you still need assistance, I would be more than happy to continue working with you on this - just let me know in a reply.
Levi