Re: [WIRELESS-LAN] Self-assigned IP on Macs
Date:Thu, 27 Aug 2009 15:58:39 -0500 From:Hector J Rios hr...@lsu.edu Subject: 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. I had the same problem after ugrading from 4.2.something to 5.2.193.0. Uncheck Enable DHCP Proxy under controller-advanced-DHCP and see if that fixes it. It worked for me. -- Earl Barfield -- Academic Research Tech / Information Technology Georgia Institute of Technology, Atlanta Georgia, 30332 Internet: earl.barfi...@oit.gatech.edue...@gatech.edu ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
RE: [WIRELESS-LAN] Interesting Numbers...
Here are some numbers for the our first week of classes: Average Number of Users by Protocol 802.11a: 772.2 802.11b: 32.2 802.11g: 3245.6 802.11n (5 GHZ): 189.7 802.11n (2.4 GHZ): 218.3 DHCP Active Leases Stats for Network in the Dorms (1hr leases; 4938 beds) Wired: Average 1.02k Maximum 1.24k Wireless: Average 1.18k Maximum 2.20k All of our dorms are 100% wireless and wired. We block peer-to-peer and other protocols on the wireless network, so the numbers above might explain why we are still seeing a lot of wired users. Two Day Averages (Monday and Tuesday) Number of Sessions: 10768.07 Number of Users: 4113.64 Number of Unique Users: 3657.42 Number of New Users: 36.85 Number of Users per AP: 2.78 Average Session Time (Minutes): 19.38 Average Session Time per User (Minutes): 49.15 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/.
Re: [WIRELESS-LAN] Self-assigned IP on Macs...
We have seen this issue to some degree. It did not happen to all Macs but only to a small percentage of machines. In case anyone should run into it though what I found was the following... It is normal for dhcp clients to request their last used IP. Something about how the Mac dhcp clients were doing it seemed to be different though. I haven't had time to do a thorough analysis of Mac dhcp behavior. That aside, what I noticed was that the clients having the trouble showed up in the controller logs as being put into an Exclusion state. This was because the controllers security mechanism was kicking in and excluding the client because of IP theft or reuse. By disabling the IP theft or Reuse under security, wireless protection policies, client exclusion policies caused it to stop happening. Looking into it further, the clients that were being blocked were coming in with addresses in the 192.168.1.x range. This is probably the most common range for home networking so it's no surprise they would have that address range coming in from home. I see two possibilities why it triggered IP theft. The first possibility is that another client had come in under that address and the second one gets blocked. The more likely cause I think is that we have the service vlan on the controllers numbered in the 192.168.1.0/24 subnet just as the wism setup docs show. I think this IP space is colliding with the clients coming in and trying to use it. My guess is that the controllers see the space in use by themselves and flag it. I have not had time however to test this theory. I also do not know why the problem was only exhibited by Macs. Seems to be something different in their dhcp client behavior. -Matt - Original Message - *From:* Hector J Rios mailto:hr...@lsu.edu *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU mailto: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 -- Matt Grover === University of Florida Sr. Network Engineer=== http://net-services.ufl.edu m...@ufl.edu=== Florida Lambda Rail (352)273-1061 === http://www.flrnet.org/ ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] Self-assigned IP on Macs...
The IP theft function can't trigger until the controller actually see an IP in use. So they wouldn't exclude the client before it had even tried to use an address much less completed the dhcp process. The exclusion triggered BECAUSE of the 192.168.1.x address. I also believe in packet captures that we saw DHCPREQUEST packets from the client asking for a specifc 192.168.1.x address. This seems to indicate it was using the address previously. The server answered with an DHCPOFFER from a different configured range. The client however would not take it or did not get it. When the IP theft function was turned off the client would then complete the dhcp process normally. Also, this did not always happen. From talking to one student it was generally exhibited when he first came in and had used the host on his home network previously. -Matt Methven, Peter J wrote: Just for information MAC OS/X Leopard (and probably Tiger) both default to an IP Address in the 192.168.1.n range when they cannot acquire an IP address, like windows machines default to a 169.254.n.n ip address. Presumably if they are being excluded from network access and not acquiring an IP address from DHCP they will fall back to a self-assigned IP address. Many Thanks Peter -Original Message- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:wireless-...@listserv.educause.edu] On Behalf Of Matt Grover Sent: 28 August 2009 15:10 To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Self-assigned IP on Macs... We have seen this issue to some degree. It did not happen to all Macs but only to a small percentage of machines. In case anyone should run into it though what I found was the following... It is normal for dhcp clients to request their last used IP. Something about how the Mac dhcp clients were doing it seemed to be different though. I haven't had time to do a thorough analysis of Mac dhcp behavior. That aside, what I noticed was that the clients having the trouble showed up in the controller logs as being put into an Exclusion state. This was because the controllers security mechanism was kicking in and excluding the client because of IP theft or reuse. By disabling the IP theft or Reuse under security, wireless protection policies, client exclusion policies caused it to stop happening. Looking into it further, the clients that were being blocked were coming in with addresses in the 192.168.1.x range. This is probably the most common range for home networking so it's no surprise they would have that address range coming in from home. I see two possibilities why it triggered IP theft. The first possibility is that another client had come in under that address and the second one gets blocked. The more likely cause I think is that we have the service vlan on the controllers numbered in the 192.168.1.0/24 subnet just as the wism setup docs show. I think this IP space is colliding with the clients coming in and trying to use it. My guess is that the controllers see the space in use by themselves and flag it. I have not had time however to test this theory. I also do not know why the problem was only exhibited by Macs. Seems to be something different in their dhcp client behavior. -Matt - Original Message - *From:* Hector J Rios mailto:hr...@lsu.edu *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU mailto: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 -- Matt Grover === University of Florida Sr. Network Engineer=== http://net-services.ufl.edu m...@ufl.edu=== Florida Lambda Rail (352)273-1061 === http://www.flrnet.org/ ** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
Re: [WIRELESS-LAN] Self-assigned IP on Macs...
We also have DHCP required set to off as well as IP Theft and reuse off and still have the problem show up. It seems after 1 to 5 tries the Mac will finally get a lease and work. Not a very popular workaround. Robert Owens Kansas State University - Original Message - From: Hector J Rios To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Sent: Friday, August 28, 2009 12:51 PM Subject: Re: [WIRELESS-LAN] Self-assigned IP on Macs... IP Theft and DHCP required are all turned off. We've never had them enabled. Still no luck. I've even tried it with the internal DHCP server in the WiSMs and it doesn't make a difference. We have Cisco and Apple involved. We'll give you guys an update if we find something. Hector ** 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/.
