You name it, we have it. Last count, we have 51 Apple TV's, but they aren't on the same network we're having problems with. The TV's are either hard-wired or registered on a Wireless network that's not secure and doesn't require any authentication...just registration.
I'm not a MAC guys at all, so do all MACs have this feature? Can a MAC laptop that is on our secure network do the same thing the Apple TV does and create this problem? It's happening on Iphones/Apple Laptops about 98% of the time, but only on the secured network. I asked if there was a "secret" update that Apple may have pushed out a few weeks ago when it started, but no one seems to know. Thanks again! Shayne -----Original Message----- From: The EDUCAUSE Wireless Issues Constituent Group Listserv [mailto:WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] On Behalf Of James Andrewartha Sent: Monday, February 27, 2017 9:15 PM To: WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU Subject: Re: [WIRELESS-LAN] MAC OSX Duplicate IP's Hi Shayne, On 28/02/17 11:10, Shayne Ghere wrote: > I’m reaching out since we just started having problems with users > complaining about getting messages on their Mac’s about a duplicate IP > address on the network. > > When looking in the ARP table of the Cisco Nexus switches, the mac > address of their computer isn’t in there, however the IP address their > machine has is owned by another mac address even though both the > Controller and Prime doesn’t see that machine associated. > > I came across an article that the Arp Cache Timeout on the 6509’s was > 300 seconds, but the Nexus (7K) has bumped it to 1500-1800 seconds > now. That jives with what I’m seeing as the disassociation time of the > original machine, and the duplicate message (within 20-25 minutes). > > The Arp-Cache timeout on the Controller is set for 1800 seconds, and > was configured that way since September 2016 (Cisco WLC 8540) with no > problems. > > This problem just cropped up within the past two weeks and is gaining > steam. Out of the 30 or so devices, 38 are Mac’s and the other two > are Windows 10 or Microsoft Surface tablets. > > If anyone else is experiencing these issues, or could point us in the > right direction, I would greatly appreciate it. Our Server/Radius > team is fairly sure it’s not on their end, yet after talking with > Cisco, I’m fairly positive it’s not the Controller/Wireless. Not > finger pointing, just asking for some advice. Do you have any Apple TVs on your network? Apple devices have a lovely feature called the Bonjour Sleep Proxy that will respond to mDNS queries for a device that is asleep. The visible side effect is what you are seeing, the IP address is owned by another MAC address. What sort of devices are the ones stealing the IP addresses? For us, the solution was to statically (via DHCP) assign IPs to the Apple TVs. Thanks, -- James Andrewartha Network & Projects Engineer Christ Church Grammar School Claremont, Western Australia Ph. (08) 9442 1757 Mob. 0424 160 877 ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/discuss.
