DHCP Persistence on C9200

[vexvoltage]

So I am going to be upfront I am out of my element a little bit with the more standard product offerings of Cisco. In the industrial Controls world (ICS) we are able to set up DHCP Persistence on things like the IE3400. Coming back to the more business side I am having a hard time finding the information to setup DHCP Persistence on a Catalyst 9200 (48 port for what its worth).

Any command examples or documentation to be shared would be super helpful.

For context I have a handful of devices that will always get plugged into the same port with DHCP enabled, and that device should be handed the same IP everytime so the PLC can pick it up. Can not use reservations or anything based on MAC Address as we will not know what they are and need to be fluid with the hardware that comes and connects. This is common for ICS architectures.

From the ICS product offerings of Cisco: https://literature.rockwellautomation.com/idc/groups/literature/documents/um/1783-um007_-en-p.pdf

[Giuseppe Larosa · Accepted solution]

Hello @vexvoltage ,

if you want to have the DHCP offered IP address to be tied to the switch port

see

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9200/software/release/16-12/configuration_guide/ip/b_1612_ip_9200_cg/configuring_dhcp.html#concept_52F0E91C4D7E4E08BD7A375818C801DD

global config:

ip dhcp use subscriber-id client-id

 and

ip dhcp subscriber-id interface-name

 on EACH interface you want to use it

ip dhcp server use subscriber-id client-id

Hope to help

Giuseppe