DHCP conflicts between AppleTV and Airport Extreme repeater

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DHCP conflicts between AppleTV and Airport Extreme repeater

I have an 2013 Airport Extreme access point (in bridge mode) connected to my Internet router using a cable. I also connected my AppleTV to the same Airport Extreme using a cable. Additionally, I have an (older, 2010 or so) Airport Extreme as a wireless repeater to extend my Wi-Fi. All components are set to get an IP address via DHCP which is provided by my (Meraki) router.

All components are running most recent firmware versions and setup correctly for this setup.

The issue I have is that the AppleTV and the (old) Airport Extreme repeater are constantly causing DHCP conflicts: they both get the same IP lease everytime the DHCP is refreshed (which, for testing purposes due to this issue is now 1 hour).

Now I did quite some testing and it's not to blame to the router (used a Juniper and a Draytek with the same effect), so I suspect the issue to be in the way the (2013) Airport Extreme forwards DHCP requests onto the network.

Is this a known issue and if so, is there a way to get it sorted out (without using quickfixes like connecting the AppleTV via Wi-Fi instead of cable)?

AirPort Extreme 802.11n (5th Gen)

Posted on Mar 19, 2014 3:12 AM

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Answer 1

Mar 19, 2014 12:06 PM in response to bm14

There does seem to be some bugs when you link apple routers together, although I think the wireless extend is the better setup.

Did you upgrade the firmware on the 2013 extreme without doing a full factory reset on it?

Please do give it a try, even if you did. Full factory reset.

Redo the setup of the AE 2013 version and use all SMB naming.. if you haven't already. (short, no spaces pure alphanumeric).

Then redo the extend wireless from the Extreme.. how does it work now?

If you keep having issues, this might help.

You can use the AE plugged into the Meraki in a different mode.. I have this setup for my roku to get a different DNS and it works very well.

I gave all the screenshots in a post here.

https://discussions.apple.com/thread/5981989?answerId=25135547022#25135547022&ac_cid=tw123456#25135547?ac_cid=t w123456#

You simply limit the dhcp range in the Meraki and transfer the dhcp role over to the AE..

Give it a try.. I think the apple system might handle the DHCP pool of addresses better when the main AE is doing the dhcp serving.

Post if any of the details are not clear.

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Answer 2

bm14 Author

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Mar 23, 2014 1:27 AM in response to LaPastenague

Hi LaPastanague,

thanks for your reply and suggestions. Quite frankly, your suggestion to split up DHCP is no solution, that's a workaround that indeed works fine (tried that already but the downside is I have no central overview of DHCP leases anymore). I'd really just like to use my router for that and I see no reason why using such a central DHCP should cause the issues I'm seeing - unless maybe there's a bug in the AE software indeed.

I tried your other suggestions though:

- Resetting the (2013) AE to factory default and reconfiguring: no effect;

- Abbreviating the device name to 'old SMB style': no effect (but then again, we're using SMB2 these days so that indeed should have no effect. Also Bonjour will 'fix' spaces and long names in addressing internally in my experience, and the Meraki dashboard seems to have no problems with it either).

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Answer 3

bm14 Author

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Mar 23, 2014 1:42 AM in response to bm14

I'd like to add some details to the issue I'm seeing:

The mentioned DHCP conflicts only occur between a wired and a wireless device connected to the same Airport Extreme in Bridge Mode, OR (less common) between any connected Wireless device and the Airport Extreme itself.

The issue is most commonly seen when conflicting devices either request or update a DHCP lease with a relatively short time from eachother (within a minute or so).

The central DHCP device (my Meraki router) logs that both conflicting devices are claiming the same IP. Even specifying a DHCP reservation does not fix the conflict as the duplicate claims persist.

To me this leads to the conclusion that either the DHCP forwarding or claim broadcasting via the Airport Extreme in Bridge Mode is faulty when devices are connected to it both wired and wireless.

Devices connected via a wireless repeater that is extending the AE's Wi-Fi do not seem to have any DHCP issues.

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Answer 4

turbostar

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2,941 points

Mar 23, 2014 6:06 AM in response to bm14

do you still have the old extreme setup to wirelessly extend right now? if so, go run some speed tests in the corners where you're trying to extend the wifi. see below, i almost recommend against wirelessly extending the network for most cases, and since you have the ac 'tower' extreme, i think that 2nd extreme is overkill - unless there's something about your space that requires the old extreme.

unplug the old extreme (for now)

factory reset the meraki router

factory reset your ac extreme (again, i know) and connect it via bridge mode to the router

plug your appletv back into the ac extreme

after factory resets, don't change anything in settings except (1) turn off wifi on meraki and (2) have ac extreme creating a new wifi name (call it testwifi123)

if you make any other changes, let me know what you changed

do you have any other gear that is connected to your network

let the setup stay on for 5 minutes and go back in the corners and run the same speedtests, report back the speeds with the old extreme and without

In the case of a wirelessly extended network, throughput may be reduced to less than 60 percent of that of a single device.

http://support.apple.com/kb/HT4145

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Answer 5

bm14 Author

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Mar 23, 2014 12:27 PM in response to turbostar

Hi turbostar,

thanks for your reply but that really has nothing do with the issue... I am aware of the repeater implications and the (2013) Airport Extreme is the only device acting as Access Point.

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Answer 6

bm14 Author

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Mar 23, 2014 12:31 PM in response to LaPastenague

Hi LaPastanague,

actually, now that I have the setup with the (2013) Airport Extreme acting in "DHCP (no NAT)" mode is running for some hours the issue got worse: now all (Wireless) devices are requesting DHCP leases from both the Airport AND the router and the DHCP log is full with duplicate lease notifications, so that underlines my suspicion that the Airport does not handle DHCP (at least the broadcast part of it) correctly.

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Answer 7

turbostar

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Mar 23, 2014 12:54 PM in response to bm14

your entitled to your opinion, but i had a similar setup with the same conflicts myself before fixing the issue

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Answer 8

bm14 Author

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Mar 23, 2014 1:19 PM in response to turbostar

I can motivate my opinion if you like:

- You're focussing on speed: I don't have a speed issue at all (I'm aware it drops due to the mesh nature of repeating). With the repeater setup both speed and coverage are fine for normal use.

- The extended Wi-Fi setup is needed temporarily as long as I don't have a cable available in the location where the repeater is located, there's no other way at this time.

- I need it extended because I live in an old brick house with a high level of iron used in the bricks, as well as steel reinforcement throughout the house and aluminum insulation under the wooden floors. If I walk around the corner from where the 2013 Airport Access Point is Wi-Fi signal drops from 100% to 70% already.

- There is no use in factory resetting a Meraki since it is cloud managed and it also doesn't have Wi-Fi (it's an MX-60). Apart from that the router is not the cause of the DHCP issues since other routers I have laying around here (Netscreen, Juniper, Draytek) show the same behavior.

That leaves factory resetting both Apple Airports again with everything detached which I've done a couple of times already to no avail.

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Answer 9

turbostar

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Mar 23, 2014 4:37 PM in response to bm14

that's helpful, but i'm not focused on speed per se, but that might be a secondary benefit. in my setup, verizon router/bridged extreme/wirelessly extended extreme i had lots of IP conflicts and was explained to me that there was likely just enough latency by the 2nd extreme going back to the 1st extreme going back to the verizon box that a window existed where the verizon box issued an IP before getting full information about potential conflicts residing on other boxes.

whether or not this is technically correct is beyond me, but i removed my 2nd extreme and everything worked.

but i have other questions. so your meraki gets an IP conflict, it doesn't then resolve the conflict on its own? and if you don't want to deal with troubleshooting, why not just give static IPs to your clients off the meraki router?

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Answer 10

bm14 Author

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Mar 23, 2014 10:39 PM in response to turbostar

Ah... now I see where you're coming from. That latency impact indeed sounds viable, were it not that the issue is between a wired device (Apple TV) and the repeater itself. Also, DHCP should be able to cope with such events.

I set the 2 AE's up with static IP's yesterday, no DHCP. The Apple TV should get a reserved IP via the Meraki (via DHCP). Now this morning I still see the IP conflicts arise every hour mentioning the repeater as a DHCP client claiming the IP of the Apple TV. Since I set the repeater to static I still stand with my view that the broadcast forwarding of the Airport is faulty because I don't see any other way this can occur.

And yes, the Meraki fixes the issue internally but still logs the conflict (as it should).

So for now I guess I'll just need to speed up getting my cable through the building to get this 'fixed'.

Does any of you know how to file a bug report with Apple?

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Answer 11

Mar 24, 2014 2:49 AM in response to bm14

I noticed that you have a Meraki as gateway. I have the same issue with the MX60 and the Z1.

Apple TV is causing IP conflict with Time Capsule, Airport Extreme and Airport Express.

I think it's the combination of Meraki+Apple that does the bug.

Meraki has just open the user discussions in the Dashboard, maybe we should post something there.

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Answer 12

bm14 Author

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Mar 24, 2014 6:37 AM in response to Spatspock315

Hi Spatspock315,

good to hear I'm not the only one with these issues. With Juniper, Netscreen and Draytek router the issues are still there though, although not as common and persistent as with the Meraki (but then, I only used those for testing and am running the Meraki fulltime so have no real comparison). The issues pop up also between other wired/wireless "pairs" (like a Mac Mini and Macbook Pro for example) sometimes.

That said, I don't mind starting a discussion on Meraki side as well. Everything helps :-)

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Answer 13

ken4321

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Mar 31, 2014 9:34 AM in response to bm14

These issues may be caused by the Bonjour Sleep Proxy service.

It works by having an online device (like the Airport Extreme) respond to queries for a device that has gone to sleep (like the Apple TV). This will cause the MAC address for the Apple TV to appear to have changed.

I was having a similar issue -- IP address switching back and forth between the MAC address for the Apple TV and the Airport Extreme. It persisted even when I gave the Apple TV a static IP. My FreeBSD DHCP server kept logging the Apple TV's static IP address going back and forth between the Apple TV and the Airport Extreme.

This thread may shed more light on the subject:

http://arstechnica.com/civis/viewtopic.php?f=10&t=1152585

I alleviated the problem to some extent by configuring the Apple TV to never go to sleep. So it never needs to register with the sleep proxy service. But I still see it when other devices (e.g. MacBook Pro) go to sleep.

One of the problems that cropped up when this was happening with the Apple TV was that the Apple Airport Utility wasn't able to see either of my two Airport Extreme routers at times, despite the fact that my connection to the internet and all other internal machines worked properly. Keeping the Apple TV from sleeping seems to have helped. We'll see if it crops up again.

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Answer 14

bm14 Author

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Apr 9, 2014 1:01 PM in response to ken4321

Hi Ken4321,

I never heard of that 'feature' and it took me some time to determine if this indeed was the cause but it sure looks like it; sniffing broadcasts for source MAC's confirms it.

I managed to circumvent the log flooding a bit by extending the DHCP lease time to 1 week (max) in the Meraki dashboard but that's all I can do about it so I'll just need to accept this side-effect I guess.

Thanks for you pointing me in the right direction!

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Answer 15

Jun 11, 2014 2:15 PM in response to ken4321

I'm also running a meraki mx60, 2013 extreme (as a remote airplay device), apple TV 2 and a macbook pro and I constantly get notified by the meraki of IP conflicts between the three apple devices, but I don't ever see any degredation in performance. It's really odd, but this has put my mind to rest. I've tried resetting everything to defaults but I had no joy. Just annoying that I keep getting the notifications, I could turn them off, but I turned them on for another unassociated problem with a maverick windows machine that likes to flaunt the rules of DHCP and do it's own, annoying, thing. Anywho...

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