12-21-2017 10:53 AM - edited 03-08-2019 01:11 PM
I would think the answer to this is pretty simple, but I can't confirm.
At one of our remote locations, we have a layer 3 switch (Cisco 3850) that has a DHCP pool configured for our IP phones. However, on the VLAN interface for the phone VLAN, we also have a helper-address configured. Configurations are below:
ip dhcp pool VOIP
network 10.1.26.0 255.255.255.0
default-router 10.1.26.1
interface Vlan500
ip address 10.1.26.1 255.255.255.0
ip helper-address 192.168.10.10
ip helper-address 192.168.20.10
If the helper address is configured on the SVI, does the local pool on the switch simply override the helper-address? The pool on the switch is responding to the queries and successfully handing out the IP address leases.
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12-21-2017 11:13 AM
The only information I found is this: https://supportforums.cisco.com/t5/lan-switching-and-routing/dhcp-local-pool-dhcp-helper-address/td-p/2909743
Hope this helps.
12-21-2017 11:07 AM
Not certain that one negates the other. My logic would be that it's faster to get a response from the local DHCP pool rather than convert the request to unicast, forward to your remote DHCP server and receive a response. Thus, the local pool would win.
12-21-2017 11:13 AM
The only information I found is this: https://supportforums.cisco.com/t5/lan-switching-and-routing/dhcp-local-pool-dhcp-helper-address/td-p/2909743
Hope this helps.
12-21-2017 11:19 AM
Yachay, thank you for that link. My guess is what BradEast1 said in that the switch would respond more quickly than the remote DHCP server.
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