Goolgle for RFC 4436, Apple, and wireless, you'll find much more on the topic.
This is worth reading, too: http://lists.sans.org/pipermail/unisog/2007-January/027056.html Frank -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Jeffrey Sessler Sent: Thursday, August 27, 2009 10:56 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Self-assigned IP on Macs... It's likely that you have "require DHCP" enabled on the Cisco controller. This is akin to Cisco DHCP Snooping with IP Source Verify. Once the Mac tries to use the same IP address without a DHCP request, it gets excluded. I'd try disabling the "Require DHCP" on the Cisco controller and see what happens. Jeff >>> Hector J Rios <hr...@lsu.edu> 08/27/09 6:58 PM >>> Brian, We are seeing the same thing. Running tcpdump on the Mac computer we see the last known address and we also see the address that our DHCP server offers but the client continues to use its last IP. Hector From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Fruits, Brian Sent: Thursday, August 27, 2009 7:51 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Self-assigned IP on Macs... I have seen similar behavior with Macs and iPhones where the first DHCP request is for (and sometimes from) their last known IP address. If DHCP fails they will sometimes continue to use their last IP. ----------------------------------- Brian Fruits UNC Charlotte ITS, Network Services bdfru...@uncc.edu ----------------------------------- If you are not the intended recipient of this transmission or a person responsible for delivering it to the intended recipient, any disclosure, copying, distribution, or other use of any of the information in this transmission is strictly prohibited. If you have received this transmission in error, please notify me immediately by reply email or by telephone at 704-687-3100. Thank you. From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Robert Owens Sent: Thursday, August 27, 2009 5:36 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Self-assigned IP on Macs... We have seen a number of Mac's getting put into exclusion because they are trying to use an IP address that has already been assigned to another device. at least that is the implication from looking at the WISM logs. Does anyone know how apple handles DHCP leasing? Especially when they are just being powered up? We speculate that they are trying to attach to their previous IP when in the world of large networks that IP could be handed out to another client but don't know for sure. Bob Owens Kansas State University ----- Original Message ----- From: Hector J Rios <mailto:hr...@lsu.edu> To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Sent: Thursday, August 27, 2009 3:58 PM Subject: [WIRELESS-LAN] Self-assigned IP on Macs... Have you guys run into this issue? We run Cisco's lightweight APs on WiSMs running code 5.2.193. Mac will associate to our APs but just won't obtain an IP address. In the end it assigns itself a self-assigned IP. We are seeing this on a lot of new MacBooks and MacBookPros running 10.5.8. If we associate the computer to an autonomous AP it works fine. If we boot it in safe mode it works fine too. Everything else it just fails. Thanks, Hector Rios Louisiana State 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/. ********** 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/. </mailto:hr...@lsu.edu></hr...@lsu.edu> ********** 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/.
