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Wireless Clients and DHCP

I want to run this by the folks out there that work in a large healthcare environment.  I have a cisco end to end wireless infrastructure.  I created a vlan for 'special' wireless devices, such as temperature sensors and other kinds of wireless medical devices.  These devices do not have a traditional operating system installed on them.  The devices are set to use dhcp from our domain controllers.  Half the scope on one DC and the other half on the remaining DC.  What I have observed is the when the device is used, it will draw an ip address from DC1.  The lease time is 7 days.  After a few minutes, the device will come back on and receive another ip address from DC2.  Also, a 7 day lease.  I cant figure out if the issue is inherent in the devices as they do not use dns or hostnames.  What I did was take a device that had a lease from both DC's.  I deleted the lease from DC2 and then reserved the lease on DC1.  The device still acquires an ip address from DC2.  I am puzzled to say the least.  if anyone has seen this before I would be appreciative to hear from you.  The DC's are server 2008 R2.  TIA

VIP Purple

This may be these supplicant

This may be these supplicant behavior. is it possible to have single scope for the vlan defined for these devices in one DC rather split them across two DC ?



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Community Member

Hey, How did you manage to


How did you manage to have DHCP load balance?

As far as I know, this can't achieved by the controller - you will need other devices

  • if proxy is enabled, it will send to both DHCPs at the same time (who answers first win)
  • If proxy is disabled, it will be fail-over DHCPs.


Try to run some DHCP debugs for one of these clients, indeed this will be interesting to check

  • debug client <MAC>
  • debug dhcp message enable




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