I have been seeing this (primarily on Apple clients) since I upgraded to 8.2.121.0 in August. We never saw this on the previous version (8.0.121.0, from May).
-----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Swartz, Pola Sent: Tuesday, December 13, 2016 1:33 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Clients unable to obtain an IP address via DHCP You want to get to the 8.2.140 code if possible. We were seeing this as well. However, there is another CCO release coming soon beyond 8.2.140. 8.2.140 has settle things down a bit for us. Smile, Pola Wireless Team Lead Sr. Wireless Administrator Department of Technology Services Denver Public Schools 720-423-3603 I Proudly Play For Team DPS Good enough... isn't -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of Bucklaew, Jerry Sent: Tuesday, December 13, 2016 12:30 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] Clients unable to obtain an IP address via DHCP You need a trace closer to the client. Most likely the offer is not making it to the client or request is not making it back to the server. Possible causes - 1. packetloss at client side 2. rouge dhcp server On 12/13/2016 02:23 PM, Atanas P Atanasov wrote: > We're a seeing some odd behavior in our wireless deployment, seemingly > random clients aren't able to obtain an IP via DHCP > > When analyzing the DHCP logs and also debugs on the wireless > controller, we see the clients sending a DHCP DISCOVER packet and the > DHCP server responds with a DHCP OFFER. However the client doesn't follow up with a DHCP REQUEST. This behavior continues sometimes for hours, until the client finally sends a DHCP REQUEST and obtains a lease. > > The side effect of this is our DHCP servers are getting long delays > when the dhcp service is restarted. We are using Infoblox dhcp severs > in a failover group. From a support case we have opened with Infoblox, they have determined that these excessive dhcp requests are increasing the number of dhcp leases in the database which causes the long restart. > > We have seen similar behavior with our wired clients but in lot smaller numbers. > > > > We're a Cisco shop, using 8450 controllers, code version is 8.2.121 > > > > Attached is a Splunk search on one of the "misbehaving" clients' MAC > > Any comments are appreciated. > > > > Atanas Atanasov > > Network Engineer > > Syracuse 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/.
