07-22-2015 11:31 AM - edited 07-05-2021 03:37 AM
Wireless controller
vlan interface
ip address 10.0.1.1/24
ip helper address 192.168.x.x (dhcp server address )
Why do we need to configure the same dhcp server ip on the wlc also
At what stage , a wireless client getting an ip address
Thanks
07-22-2015 12:31 PM
The WLC will unicast the dhcp server rather than broadcast which is the norm. So if you had the VLAN dedicated to wirelss clients you would not need to use the IP helper on that specific VLAN.
07-28-2015 01:29 AM
Hi ,
So i ll remove the ip helper address from the interface vlan ( wireless client ) , and just add on the
wlc , can you brief how the traffic flow to the back and forth to the dhcp server
Thanks for your help
07-28-2015 05:15 AM
The WLC can proxy or bridge DHCP requests
http://www.cisco.com/c/en/us/support/docs/wireless/4400-series-wireless-lan-controllers/110865-dhcp-wlc.html
07-28-2015 06:05 AM
Just to add... If you using the WLC as a dhcp server for example, then proxy for that interface needs to be enabled. Now if you have an external dhcp server, then you can either proxy the dhcp request, like what Peter mentioned, or you can let dhcp request be broadcasted out from the controller like how switches pass dhcp request. The later, you would need an ip helper to point the broadcast to the dhcp server. The traffic flow no matter what is the same... if the AP is in local mode, then all traffic including dhcp request will go to the controller and the controller will either proxy or just send that across to the wired side. If the AP is in FlexConnect and you have local switching enabled, then traffic would not be tunneled to the WLC and the traffic from the client would hit the AP and the AP would place the traffic on the wired side.
-Scott
07-31-2015 06:46 AM
sorry to Hijack, however I want to ask about DHCP
Can the builtin WLC DHCP server send option 43 to the AP's on the management interface?
Cant find anywhere to add this. So it is on the 3750 for now.
OR does it send it automatically if DHCP is enabled on the mgt interface becasue it is "smart"
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