I was wondering whether once the DHCP offer made by the DHCP server arrives at the DHCP relay agent, the relay agent is able to (assuming the network has one VLAN per subnet):
- examine the DHCP payload for the offer IP and determine what subnet the address will be on and hence
- translate that to the one VLAN in that subnet using some internal table
- tag the frame with a VLAN using .1q before entering the switch such that the FF:FF:FF:FF:FF:FF egresses to only ports of that VLAN
Or does this defy the rules of 802.1q tagging; would the switch remove this tag if it were placed before entering the switch at the access port.