Cisco c9800-L Internal DHCP Issue

[NickChalker]

I am fairly new to the c9800 WLC and have been asked to move one of the WLAN DHCP scopes to the c9800 due to reasons outside of our control, I appreciate best practise advise against this, but needs must. Ultimately the scopes will be housed on external DHCP but at this present time it is not possible.

Information:

Device: c9800-L pair using RP+RMI
Code: 17.3.4c
Boot Mode: Install
WLAN Switching Mode: Local
OOB Admin Port: x.x.x.x/24
Wireless Management with SVI: y.y.y.10/24
WLAN1 with SVI: z.z.z.z/23
There are 4 other VLAN's with SVI's for WLAN's

 I configured a standard DHCP scope (Name, Type, Address, Subnet, Start IP, End IP, Lease, Router and DNS. Reserved left Disabled) and applied the DHCP option to the Profile Policy for the WLAN using the WMI address for the DHCP server. Once applied I could see in DHCP Clients Monitoring that addresses where being allocated but some of the addresses allocated where on the correct VLAN under interface and appeared to be working but a number where allocated on the WMI VLAN under interface and didn't work.

Unfortunately due to time constraints I wasn't able to perform any packet captures etc.

Any assistance would be greatly received.

[Kasun Bandara]

try enabling proxy in DHCP

[NickChalker]

Thank you very much for your very quick response. Doesn't DHCP proxy utilise the virtual IP address and also stop any static IP addresses from being used.

I will investigate and update accordingly

Thank you again

[balaji.bandi]

thre may be small config missing here, like VLAN tagging, check the settings agains :

refer below guide :

https://www.youtube.com/watch?v=ALgKHOv-26c

https://wifininjas.net/2019/08/06/wn-blog-007-c9800-wlc-internal-dhcp-server-config/

https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/config-guide/b_wl_16_10_cg/dhcp-for-wlans.html#Cisco_Concept.dita_cf3a1219-4b1f-432e-8ec5-42ed8a860302

[NickChalker]

Thank you for your very quick response, I followed Wifi Ninjas article and scanned through the Cisco document, I will need to go through them again and watch the YouTube link you sent, hopefully it is something simple I missed but if it was relating to VLAN tagging wouldn't all addresses fall on the wrong interface rather than some of them.

I will go through the articles again and update accordingly.

Thank you again