DHCP Server Config

[wimoody]

Silly question, but I have a router with 3 subinterfaces off of a gigabit connection. Do I need to assign a pool for each subinterface or will it know based on the interface it came from and the ip range I give it.

Also, do I need to configure a Helper address?

[wimoody]

Let me add to my previous statement.

I'm running DHCP Server on the router itself.

Can I assume that all vlan's will be able to access my DHCP server since it's Global configuration command and not an interface command, or do I still need the 'Helper'

[gokhankosem]

You can also check this DHCP Server Configs :

2 DHCP Packet Tracer Configurations

[julian.bendix]

Hey!

The router will know which pool to use by itself - because of the IP/Mask that is configured on the Subinterface where the DHCP Discover/Request arrives!

Does this answer your question or do you need further help?

Best regards
Julian

P.S. pls always mark helpful posts or solution if applicable :)

[Matt Wilson]

Sorry about hijacking a thread but I have a similar question. As per attached diagram, how would I go about serving DHCP requests from the 1941 router via an ASA to the 10.1.1.0/24 subnet? As per your answer above, the router would automatically serve the 10.1.5.0/24 subnet as it is directly connected. I've searched the internet for an answer to no avail. I don't particularly want to make the ASA the DHCP server.

[julian.bendix]

Hi Matt!

Your just configure the ASA as DHCP Relay pointing to the Router which is serving DHCP.
ASA will perform normal Relay function - it will take the DHCP Packets (Broadcasts) and send the information as Unicast towards the real DHCP.
DHCP will know which subnet to use for the Requests since the Relayed Packets are sourcing from the Interface in the correct Subnet from the ASA.

You can read through this link for further info and config example:

https://www.cisco.com/c/en/us/support/docs/security/adaptive-security-appliance-asa-software/116265-configure-product-00.html

Best regards
Julian