This may sound very basic. But I am have some subtle things to be known on DHCP and DHCP relay.
I am pretty sure that DHCP RELAY (ip helper-address) command is required if the DHCP server is in different network and in L3 environment. my understanding is below:
The DHCP server is able to provide addresses from the appropriate scope for VLANs, based on the use
of the Relay Agent field in the DHCP packets. A Relay Agent is the agent that is in charge of the conversion
of the broadcast DHCP packets sent by the client into unicast packets that are sent to the DHCP server.
This agent also converts the unicast DHCP packets sent from the DHCP server into broadcast packets that are
sent on the telephone network.
Fine, How about a pure L2 environment. Say for example I have a LAYER 2 2960 switch with VLAN 10 and 20. Please note no SVI is configured as i donot need the intervlan routing.
I have a DHCP server connected in trunk port carrying VLAN 20 and VLAN 10 of the switch. DHCP server is having 2 scope address one for VLAN 10 (10.10.10.0) and other for VLAN 20 (18.104.22.168).
In this case which parameter decides to pick/select the appropriate scope for corresponding VLANs. Do I need to configure DHCP options?
Hope I managed to explain better to your kind understanding. I tried with various sources and not able to get answers. I finally resorted your help