mnewstadt

Q: 4 Apple TV's on my office network, Keep getting IP address conflicts with each other despite being assigned reserved addresses.

4 Apple TV's on my office network, Keep getting IP address conflicts with each other despite being assigned differnt reserved addresses in DHCP

While it seems like they realize it and correct themselves it means my network notifify me of the conflict and that can mean upwards of 30 emails a day... and over a long weekend that means 90 plus emails to delete after making sure it is the same 4 mac address having the problems... how can I make this go away

Posted on Jun 2, 2016 6:49 AM

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Q: 4 Apple TV's on my office network, Keep getting IP address conflicts with each other despite being assigned reserved addresses.

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  • by Diana.McCall,

    Diana.McCall Diana.McCall Jun 2, 2016 7:01 AM in response to mnewstadt
    Level 4 (2,895 points)
    Apple TV
    Jun 2, 2016 7:01 AM in response to mnewstadt

    Since you're reserving addresses in DHCP, I assume you've set the ATVs to obtain addresses automatically. That ought to work.

    Is there any chance they're waking up on WiFi and switching to ethernet? On maybe switching from one WiFi network to another?

    Do you actually need fixed IPs?

    The alternative to reserved addresses would be to reduce the size of the DHCP pool, and set the ATV addresses staticly.

    Just incidentally, have you given the ATVs different names? That's necessary for any of the Apple protocols.

    Can you identify the versions of your ATVs,see Identify your Apple TV model - Apple Support?

  • by Phil0124,

    Phil0124 Phil0124 Jun 2, 2016 7:12 AM in response to mnewstadt
    Level 7 (26,860 points)
    iPhone
    Jun 2, 2016 7:12 AM in response to mnewstadt

    How are the IPs being assigned?

     

    Did you set the DHCP to give them an IP address based on MAC address?

     

    Are they using wifi or wired connections?

     

    How do you know its the Apple Tvs that are having the issue, and not some other device on the network attempting to use one of the reserved IPs from the Apple Tvs?

     

    Basically, this is a network config issue, and very unlikely to be related to the Apple Tvs themselves, but rather how your are assigning the IPs. 

     

    The way to resolve this, is to verify the IP assignment, and that nothing else is receiving the same IP.

  • by Diana.McCall,

    Diana.McCall Diana.McCall Jun 2, 2016 7:18 AM in response to Diana.McCall
    Level 4 (2,895 points)
    Apple TV
    Jun 2, 2016 7:18 AM in response to Diana.McCall

    Are they on WiFi or ethernet?

    Once they've received their addresses, the ATVs should keep them forever, by regularly renewing their leases. Are you doing anything to make this difficult? Like disconnecting ATV power, turning off WiFi radios (if on WiFi), etc.? What are the lease durations?

  • by mnewstadt,

    mnewstadt mnewstadt Jun 2, 2016 7:58 AM in response to Diana.McCall
    Level 1 (4 points)
    Apple TV
    Jun 2, 2016 7:58 AM in response to Diana.McCall

    Apple TV 4's latest update according to the devices, reserved by mac address, yes they have different names they are on Ethernet, dhcp lease 1 day...

  • by Phil0124,

    Phil0124 Phil0124 Jun 2, 2016 8:38 AM in response to mnewstadt
    Level 7 (26,860 points)
    iPhone
    Jun 2, 2016 8:38 AM in response to mnewstadt

    Are they being assigned from a range of IPs?    Why are you limiting the lease to one day?

     

    Its conceivable, one apple TV is renewing its lease, and getting an IP still being used by another, that has expired, but has not yet renewed if its asleep. so as soon as it comes back online and has not yet renewed the lease, it generates a conflict.

     

    Have you tried assigning one specific IP to each Apple TV instead of a range of IPs?

  • by Diana.McCall,

    Diana.McCall Diana.McCall Jun 2, 2016 8:43 AM in response to mnewstadt
    Level 4 (2,895 points)
    Apple TV
    Jun 2, 2016 8:43 AM in response to mnewstadt

    Sounds simple. Some users have reported losing WiFi while sleeping, but works fine for others. You're on ethernet, so should not be a problem, although the interfaces are different. I wonder if they're somehow failing to renew, causing the router to reclaim the addresses, then they wake up, thinking they still own the address, causing consternation. Are the ATVs losing power? Static addresses may the viable solution.

    When you get the reports, do you see the ATVs using each other's address, or is each one just conflicting with its own address. Hard to believe they'd want to steal another's address.

  • by mnewstadt,

    mnewstadt mnewstadt Jun 2, 2016 9:50 AM in response to Diana.McCall
    Level 1 (4 points)
    Apple TV
    Jun 2, 2016 9:50 AM in response to Diana.McCall

    So this pretty well describes the behavior, with the exception of the fact that all but 1 of these devices were brand new still in the box wrapped in plastic..not used on other networks...

    https://documentation.meraki.com/MX-Z/Monitoring_and_Reporting/IP_Conflict_Event s_Triggered_by_iOS_Devices

     

     

    they were on normal DHCP addresses for a few days where I got lots amounts of IP address conflicts..  so I set them to get reserved addresses by mac address (one ip address per mac address) and went around and set the names..

     

    I really don't want to set the IPs on them static because there is a chance they could be taken to different networks temporally and then brought back here..

  • by Phil0124,

    Phil0124 Phil0124 Jun 2, 2016 11:28 AM in response to mnewstadt
    Level 7 (26,860 points)
    iPhone
    Jun 2, 2016 11:28 AM in response to mnewstadt

    If you are giving them 1 IP address option per MAC Address, then there should be no conflicts between them, as each Apple Tv would be the one using a single address.

     

    Its possible the lease renewal is causing an issue since it will always try to assign the same IP address to the same Apple Tv. If the Apple Tv tries to use an IP at the same time its being renewed the issue explained in the link above may occur.

     

    Do your logs tell you which IPs are causing the issues?  Or are all 4 causing the conflicts?

     

    Can you set your network to not warn you about events with these specific IPs?\

     

    Perhaps increase the lease time from the DHCP?

  • by Diana.McCall,

    Diana.McCall Diana.McCall Jun 2, 2016 11:52 AM in response to mnewstadt
    Level 4 (2,895 points)
    Apple TV
    Jun 2, 2016 11:52 AM in response to mnewstadt

    Right, but they're just sitting there on your network, renewing their leases, and so there should never be a problem.

    That's why I'm asking if they are being powered down, as opposed to sleeping. Because if the power's off, the router will cancel the lease and reclaim the address. When the device powers up, it will try to reuse the address, which it no longer owns, causing the conflict reported in the article you referenced. Or are they being physically disconected from the network? Are they on something like a TV cart that's only connected to power and network when it's in use? If the ATVs are sleeping, they will maintain their leases. (Actually, I'm checking this. I moved my ATV 4 to ethernet this morning. Need to wait until tomorrow to see if the ethernet lease renews as expected. I know it works on WiFi.) If mobility is essential, static IPs may be the only way to stop these conflicts, unless you just disable reporting. You could buy a separate ATV for off-site use.

  • by Diana.McCall,

    Diana.McCall Diana.McCall Jun 3, 2016 5:11 AM in response to Diana.McCall
    Level 4 (2,895 points)
    Apple TV
    Jun 3, 2016 5:11 AM in response to Diana.McCall

    Results for ATV 4 on ethernet connection. Netgear R6400 router. DHCP lease duration not configurable, appears to be 24 hours when all on WiFi.

    ATV maintains lease while sleeping, but renews lease 68 times in 19.5 hours. Renewal intervals range from less than one minute to one hour. This repetitious behavior has been reported by others. While this was going on, the iPad on WiFi seems to have switched to renewing every 6 hours, so the lease time may have been changed by the router to 12 hours, but that doesn't explain the ATV4 behavior on ethernet.

    Conclusions: ATV 4 does maintain lease on ethernet while sleeping, but renews much more frequently than necessary.

  • by SW11,

    SW11 SW11 Jun 3, 2016 8:00 AM in response to Diana.McCall
    Level 1 (8 points)
    Apple TV
    Jun 3, 2016 8:00 AM in response to Diana.McCall

    I get your point on DHCP leases, but the original problem was on a static IP. This is the only device which exhibits this problem.

     

    I'm going to set a syslog server up to monitor the router and then if it happens again, I can check the log files. As you suggested, it may be something to do with being behind a switch. However, direct connection is not an option since it is on a different floor. Testing a direct connection would not be practicl as the problem happens after a month or two!

     

    Thanks anyway for your help.

  • by Diana.McCall,

    Diana.McCall Diana.McCall Jun 3, 2016 8:16 AM in response to SW11
    Level 4 (2,895 points)
    Apple TV
    Jun 3, 2016 8:16 AM in response to SW11

    Sorry to persist, but are they still connected and sleeping when not in use? If they are, my observation of apparently random lease renewal behavior may be pertinent. Since you say it goes bad after a month, who knows what this randomness may become in a month. You can search for DHCP lease renewal. The affected user had a lot of ethernet ATVs, and the renewal traffic was affecting his network and router. See AppleTV 3 floods DHCP when ethernet connected

    Cheers, Di

  • by Rudegar,

    Rudegar Rudegar Jun 3, 2016 9:03 AM in response to SW11
    Level 7 (28,334 points)
    Wireless
    Jun 3, 2016 9:03 AM in response to SW11

    using a static ip will not make the hdcp know that ip is taken and not give the same ip to other devices

  • by SW11,

    SW11 SW11 Jun 3, 2016 9:17 AM in response to Rudegar
    Level 1 (8 points)
    Apple TV
    Jun 3, 2016 9:17 AM in response to Rudegar

    i have set the static ip outside the DHCP range on the router, so this IP will not be handed out. It Marengo difference.

     

    there is something strange going on, because another issue is with Airplay. There are Airport expresses and Apple TVs All set to AirPlay. Often someone most of these disappear from the list of AirPlay devices found.

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