Phil, We ran into this issue while evaluating the 4400. Unlike XP, Vista, by default, enables the DHCP broadcast flag: http://support.microsoft.com/kb/928233 Also by default, the WLC's do not forward broadcast or multicast traffic to the wireless networks. So if your DHCP relay is on the *wrong* side of the controller, the DHCP ACKs are broadcast and get dropped at the controller. The client never sees it and continues to make requests until it gives up and decides a 169 address will solve all its problems.
So you have 4 options: 1. don't support Vista 2. hack all your Vista client registries to disable the broadcast flag 3. let the controllers be your DHCP relay 4. set the WLC to forward broadcast traffic No.4 seemed the most reasonable option for us. As Cisco strong armed us to give the 4400's back, I can't walk you through the config for allowing broadcast traffic, but there was a setting to enable multicast which also enables broadcast although that fact is not obvious from the GUI. Our SE says they plan to separate these in future code. We do not route multicast to our wireless networks anyway, so I didn't have too many concerns about allowing this for our eval. Hope this helps, Steven Lee Communications Network Services Virginia Tech -----Original Message----- From: Phil Trivilino [mailto:[EMAIL PROTECTED] Sent: Monday, May 07, 2007 2:34 PM To: [email protected] Subject: [WIRELESS-LAN] Vista DHCP and CISCO WCS/WLC Hello. We have a new installation on 3 4400/100 controllers and are just beginning rollout of 175 Aps along with converting those 1200 series Aps we have, that are capable, to LWAPP mode. Everything is going well except for Vista. We cannot get these boxes to do DHCP on our new wireless deployment. All other Oss (XP and MAC) are working flawlessly. So I am lazy and am asking if anyone here has had this problem and what their solution may have been. I looked at the list archives and do not believe the information there to be applicable to our issue. Thanks, Phil Trivilino Manager of Network Infrastructure St. Lawrence University ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
