WLC DHCP Proxy - To Do or Not to Do?

[raun.williams]

What is the upside/downside of turning of the WLC's DHCP Proxy setting?  I know the option is there now, but it still defaults to proxy mode, so whats the issues?  I ask, because, I could make a current issue of a guest wlan getting to a dhcp server a lot easier, if the client requests it. I can then dhcp relay off of a pix and to my enterprise dhcp/dns server. But I'm concerned what effect this may have on my other wlans.

[Stephen Rodriguez · Accepted solution]

Dhcp proxy is required if the WLC is the dhcp server, if you disable this remember to add the ip-helper address to your L3 interfaces.

That part of the config is a holdover from the Airespace days that helped the WLC learn the ip access of the clients. This has been fixed updated in later releases of code. So to proxy or not to proxy is really up to if the WLC is the dhcp or not. Unless yopu are running 6.0.196.0 or 7.0.980. Where you could hit CSCth68708

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[George Stefanick]

Great response Steve +5

[raun.williams]

Yes, great response Steve. Thank you!  In looking at CSCth68708, it seems to also only apply if running DHCP on the controller.  Do you know if in a wlan anchor situation, if both controllers would have to be set with DHCP Proxy off, or can only the anchor have DHCP Proxy turned off?

[Stephen Rodriguez]

I would have it off on both the inside and DMZ controller, and just set the ip-helper address to the server on the inside.

[Tony Davis]

Stephen or George,

Are there ANY implications of turning off DHCP relay(Proxy) mid-day?  Will it affect any traffic flow or dhcp activity?

Thanks,

Tony

[Stephen Rodriguez]

So long as ou have teh ip chiller address on the routed interface, you shouldn't see any interruption in service.

Steve

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[George Stefanick]

Nope .. As Steve points out you will be good so long as your have ip helpers set up ... KEEP in MIND .. If you the WLC as a DHCP server you will not be able to and you can not going forward ...