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Today's Topics:
1. Re: Apple TV 4K keeps requesting DHCP lease (Philip Prindeville)
----------------------------------------------------------------------
Message: 1
Date: Mon, 11 Aug 2025 18:32:12 -0600
From: Philip Prindeville <philipp_s...@redfish-solutions.com>
To: Users of ISC DHCP <dhcp-users@lists.isc.org>
Subject: Re: Apple TV 4K keeps requesting DHCP lease
Message-ID:
<c00cd018-3d6a-498a-b10c-c07b21922...@redfish-solutions.com>
Content-Type: text/plain; charset=utf-8
Hmm? no joy.
09:40:20.608098 9c:3e:53:0d:9f:be > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800),
length 342: (tos 0x0, ttl 255, id 18207, offset 0, flags [none], proto UDP
(17), length 328)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from
9c:3e:53:0d:9f:be, length 300, xid 0xbfefc88d, Flags [none] (0x0000)
Client-Ethernet-Address 9c:3e:53:0d:9f:be
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message (53), length 1: Request
Parameter-Request (55), length 9: Subnet-Mask (1),
Classless-Static-Route (121), Default-Gateway (3), Domain-Name-Server (6)
Domain-Name (15), Unknown (108), URL (114), Unknown (119)
Unknown (252)
MSZ (57), length 2: 1500
Client-ID (61), length 7: ether 9c:3e:53:0d:9f:be
Requested-IP (50), length 4: 192.168.6.242
Lease-Time (51), length 4: 7776000
Hostname (12), length 11: "Penthouse-6"
09:40:20.608462 ac:1f:6b:1d:fb:80 > 9c:3e:53:0d:9f:be, ethertype IPv4 (0x0800),
length 373: (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17),
length 359)
192.168.6.1.67 > 192.168.6.242.68: [udp sum ok] BOOTP/DHCP, Reply, length
331, xid 0xbfefc88d, Flags [none] (0x0000)
Your-IP 192.168.6.242
Client-Ethernet-Address 9c:3e:53:0d:9f:be
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message (53), length 1: ACK
Server-ID (54), length 4: 192.168.6.1
Lease-Time (51), length 4: 43200
Subnet-Mask (1), length 4: 255.255.255.0
Default-Gateway (3), length 4: 192.168.6.1
Domain-Name-Server (6), length 4: 192.168.6.1
Domain-Name (15), length 21: "redfish-solutions.com"
Unknown (108), length 4: 0
Unknown (119), length 23:
17.114.101.100.102.105.115.104.45.115.111.108.117.116.105.111.110.115.3.99.111.109.0
Unknown (252), length 1: 0
Either I?m not formatting the response correctly, or giving the wrong response,
or the issue is not related to those three options.
What?s weird is we have two Apple TV 4K?s, but only one of them does this.
> On Jul 27, 2025, at 10:29?PM, glenn.satch...@uniq.com.au wrote:
>
> Hi Philip,
>
> In the past when I've seen this it's often a requested dhcp-option is not
> sent in the reply. There are a couple of ones labeled as unknown:
>
> 108 - ipv6 preference
> # this is a guess
> option option-108 0;
>
> 119 - domain search
> option domain-search "example.com";
>
> 252 - wpad url for proxy configuration
> # NUL termination bug heuristic applied, and "string" won't!
> option wpad code 252 = text;
> option wpad "http://example.com/proxy.pac\000";;
>
> If the client expects to get an option and doesn't it will keep re-requesting
> as you have seen. The dhcp server won't send an unconfigured option.
>
> You may need to try a bit of experimentation with these. Maybe just sending a
> null string will work. I'd try them one at a time to see.
>
> regards,
> Glenn
>
> Perhaps comparing the packet trace with one of your working older Apple TVs
> will show a difference. It should be easy enough to fill in an appropriate
> value to see if it makes a difference. I don't know
> On 2025-07-28 03:00, Philip Prindeville wrote:
>>> On Jul 24, 2025, at 12:56?PM, Barry Stear <bst...@gmail.com> wrote:
>>> Hi Phillip,
>>> Looking at the tcpdump the issue looks to be caused by three things :
>>> 1) Both of your Apple TV's have a hostname of Penthouse-6
>> No, that?s the two MAC addresses of one of the Apple TV?s, Ethernet and
>> WiFi. We do that for all of the devices that have two interfaces, or WiFi
>> and a wired docking station.
>>> 2) Your configuration file specified a hostname of "Penthouse" for both of
>>> the MAC addresses which does not match either of them so they are not
>>> getting assigned the IP address that you are wanting
>>> 3) You specified both of them should get an ip address of 192.168.6.242
>>> which is not possible.
>> Whether ?Penthouse? is on WiFi or wired Ethernet, it should get the same
>> address.
>> It?s curious that it?s doing DHCP on both interfaces even though in the
>> setup, I?ve explicitly selected Ethernet. It didn?t used to do that.
>>> To resolve this, you need to rename one of your Apple TV's to another name,
>>> perhaps Penthouse-5 and then update the configuration file to match the mac
>>> address with the correct Hostname. Below, I highlighted the Request with
>>> the MAC address and Hostname coming in the DHCP request message from the
>>> Apple TV's as well as where you specified Penthouse as the hostname in your
>>> configuration file.
>>> host Penthouse-9c3e530d9fbe {
>>> hardware ethernet 9c:3e:53:0d:9f:be;
>>> fixed-address 192.168.6.242;
>>> option host-name "Penthouse";
>>> if exists dhcp-parameter-request-list {
>>> option dhcp-parameter-request-list = concat(option
>>> dhcp-parameter-request-list, 3a);
>>> }
>>> }
>> This is the wired interface. The adding of (n) is something that Avahi does
>> when it detects a collision on the name.
>>> host Penthouse-9c3e5309d1c5 {
>>> hardware ethernet 9c:3e:53:09:d1:c5;
>>> fixed-address 192.168.6.242;
>>> option host-name "Penthouse";
>>> if exists dhcp-parameter-request-list {
>>> option dhcp-parameter-request-list = concat(option
>>> dhcp-parameter-request-list, 3a);
>>> }
>>> 00:07:22.605432 9c:3e:53:09:d1:c5 > ff:ff:ff:ff:ff:ff, ethertype IPv4
>>> (0x0800), length 342: (tos 0x0, ttl 255, id 22192, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from
>>> 9c:3e:53:09:d1:c5, length 300, xid 0x87ec8a54, secs 1, Flags [none] (0x0000)
>>> Client-Ethernet-Address 9c:3e:53:09:d1:c5
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: Request
>>> Parameter-Request (55), length 9: Subnet-Mask (1),
>>> Classless-Static-Route (121), Default-Gateway (3), Domain-Name-Server (6)
>>> Domain-Name (15), Unknown (108), URL (114), Unknown (119)
>>> Unknown (252)
>>> MSZ (57), length 2: 1500
>>> Client-ID (61), length 7: ether 9c:3e:53:09:d1:c5
>>> Requested-IP (50), length 4: 192.168.6.242
>>> Lease-Time (51), length 4: 7776000
>>> Hostname (12), length 11: "Penthouse-6"
>>> 00:07:22.605800 ac:1f:6b:1d:fb:80 > 9c:3e:53:09:d1:c5, ethertype IPv4
>>> (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 192.168.6.1.67 > 192.168.6.242.68: [udp sum ok] BOOTP/DHCP, Reply,
>>> length 300, xid 0x87ec8a54, secs 1, Flags [none] (0x0000)
>>> Your-IP 192.168.6.242
>>> Client-Ethernet-Address 9c:3e:53:09:d1:c5
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: ACK
>>> Server-ID (54), length 4: 192.168.6.1
>>> Lease-Time (51), length 4: 43200
>>> Subnet-Mask (1), length 4: 255.255.255.0
>>> Default-Gateway (3), length 4: 192.168.6.1
>>> Domain-Name-Server (6), length 4: 192.168.6.1
>>> Domain-Name (15), length 21: "redfish-solutions.com"
>>> 00:07:24.859045 9c:3e:53:0d:9f:be > ff:ff:ff:ff:ff:ff, ethertype IPv4
>>> (0x0800), length 342: (tos 0x0, ttl 255, id 22193, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from
>>> 9c:3e:53:0d:9f:be, length 300, xid 0xbfede3b8, Flags [none] (0x0000)
>>> Client-Ethernet-Address 9c:3e:53:0d:9f:be
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: Request
>>> Parameter-Request (55), length 9: Subnet-Mask (1),
>>> Classless-Static-Route (121), Default-Gateway (3), Domain-Name-Server (6)
>>> Domain-Name (15), Unknown (108), URL (114), Unknown (119)
>>> Unknown (252)
>>> MSZ (57), length 2: 1500
>>> Client-ID (61), length 7: ether 9c:3e:53:0d:9f:be
>>> Requested-IP (50), length 4: 192.168.6.242
>>> Lease-Time (51), length 4: 7776000
>>> Hostname (12), length 11: "Penthouse-6"
>>> On Thu, Jul 24, 2025 at 12:19?AM Philip Prindeville
>>> <philipp_s...@redfish-solutions.com> wrote:
>>> Hi,
>>> I have a couple of Apple TV?s that keep harassing my DHCP server, which is
>>> 4.4.3-P1.
>>> Traces are below.
>>> The config for my server looks like:
>>> authoritative;
>>> ddns-domainname "redfish-solutions.com.";
>>> ddns-update-style standard;
>>> ddns-updates on;
>>> ignore client-updates;
>>> update-static-leases on;
>>> use-host-decl-names on;
>>> update-conflict-detection off;
>>> update-optimization off;
>>> ?
>>> log-facility daemon;
>>> default-lease-time 3600;
>>> max-lease-time 86400;
>>> option domain-name "redfish-solutions.com";
>>> # additional codes
>>> option classless-ipv4-route code 121 = array of { unsigned integer 8 };
>>> ?
>>> subnet 192.168.6.0 netmask 255.255.255.0 {
>>> option subnet-mask 255.255.255.0;
>>> option broadcast-address 192.168.6.255;
>>> deny unknown-clients;
>>> default-lease-time 43200;
>>> max-lease-time 43200;
>>> option routers 192.168.6.1;
>>> option domain-name-servers 192.168.6.1;
>>> }
>>> ?
>>> host Penthouse-9c3e530d9fbe {
>>> hardware ethernet 9c:3e:53:0d:9f:be;
>>> fixed-address 192.168.6.242;
>>> option host-name "Penthouse";
>>> if exists dhcp-parameter-request-list {
>>> option dhcp-parameter-request-list = concat(option
>>> dhcp-parameter-request-list, 3a);
>>> }
>>> }
>>> host Penthouse-9c3e5309d1c5 {
>>> hardware ethernet 9c:3e:53:09:d1:c5;
>>> fixed-address 192.168.6.242;
>>> option host-name "Penthouse";
>>> if exists dhcp-parameter-request-list {
>>> option dhcp-parameter-request-list = concat(option
>>> dhcp-parameter-request-list, 3a);
>>> }
>>> }
>>> I?ve provisioned both the Ethernet and WiFi MAC addresses but the TV?s are
>>> hardwired.
>>> The tcpdumps look like:
>>> 00:07:22.605432 9c:3e:53:09:d1:c5 > ff:ff:ff:ff:ff:ff, ethertype IPv4
>>> (0x0800), length 342: (tos 0x0, ttl 255, id 22192, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from
>>> 9c:3e:53:09:d1:c5, length 300, xid 0x87ec8a54, secs 1, Flags [none] (0x0000)
>>> Client-Ethernet-Address 9c:3e:53:09:d1:c5
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: Request
>>> Parameter-Request (55), length 9: Subnet-Mask (1),
>>> Classless-Static-Route (121), Default-Gateway (3), Domain-Name-Server (6)
>>> Domain-Name (15), Unknown (108), URL (114), Unknown (119)
>>> Unknown (252)
>>> MSZ (57), length 2: 1500
>>> Client-ID (61), length 7: ether 9c:3e:53:09:d1:c5
>>> Requested-IP (50), length 4: 192.168.6.242
>>> Lease-Time (51), length 4: 7776000
>>> Hostname (12), length 11: "Penthouse-6"
>>> 00:07:22.605800 ac:1f:6b:1d:fb:80 > 9c:3e:53:09:d1:c5, ethertype IPv4
>>> (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 192.168.6.1.67 > 192.168.6.242.68: [udp sum ok] BOOTP/DHCP, Reply,
>>> length 300, xid 0x87ec8a54, secs 1, Flags [none] (0x0000)
>>> Your-IP 192.168.6.242
>>> Client-Ethernet-Address 9c:3e:53:09:d1:c5
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: ACK
>>> Server-ID (54), length 4: 192.168.6.1
>>> Lease-Time (51), length 4: 43200
>>> Subnet-Mask (1), length 4: 255.255.255.0
>>> Default-Gateway (3), length 4: 192.168.6.1
>>> Domain-Name-Server (6), length 4: 192.168.6.1
>>> Domain-Name (15), length 21: "redfish-solutions.com"
>>> 00:07:24.859045 9c:3e:53:0d:9f:be > ff:ff:ff:ff:ff:ff, ethertype IPv4
>>> (0x0800), length 342: (tos 0x0, ttl 255, id 22193, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from
>>> 9c:3e:53:0d:9f:be, length 300, xid 0xbfede3b8, Flags [none] (0x0000)
>>> Client-Ethernet-Address 9c:3e:53:0d:9f:be
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: Request
>>> Parameter-Request (55), length 9: Subnet-Mask (1),
>>> Classless-Static-Route (121), Default-Gateway (3), Domain-Name-Server (6)
>>> Domain-Name (15), Unknown (108), URL (114), Unknown (119)
>>> Unknown (252)
>>> MSZ (57), length 2: 1500
>>> Client-ID (61), length 7: ether 9c:3e:53:0d:9f:be
>>> Requested-IP (50), length 4: 192.168.6.242
>>> Lease-Time (51), length 4: 7776000
>>> Hostname (12), length 11: "Penthouse-6"
>>> 00:07:24.859370 ac:1f:6b:1d:fb:80 > 9c:3e:53:0d:9f:be, ethertype IPv4
>>> (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 192.168.6.1.67 > 192.168.6.242.68: [udp sum ok] BOOTP/DHCP, Reply,
>>> length 300, xid 0xbfede3b8, Flags [none] (0x0000)
>>> Your-IP 192.168.6.242
>>> Client-Ethernet-Address 9c:3e:53:0d:9f:be
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: ACK
>>> Server-ID (54), length 4: 192.168.6.1
>>> Lease-Time (51), length 4: 43200
>>> Subnet-Mask (1), length 4: 255.255.255.0
>>> Default-Gateway (3), length 4: 192.168.6.1
>>> Domain-Name-Server (6), length 4: 192.168.6.1
>>> Domain-Name (15), length 21: "redfish-solutions.com?
>>> 00:07:34.809046 58:d3:49:e7:ca:37 > ff:ff:ff:ff:ff:ff, ethertype IPv4
>>> (0x0800), length 342: (tos 0x0, ttl 255, id 38810, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from
>>> 58:d3:49:e7:ca:37, length 300, xid 0x27e24d21, Flags [none] (0x0000)
>>> Client-Ethernet-Address 58:d3:49:e7:ca:37
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: Request
>>> Parameter-Request (55), length 9: Subnet-Mask (1),
>>> Classless-Static-Route (121), Default-Gateway (3), Domain-Name-Server (6)
>>> Domain-Name (15), Unknown (108), URL (114), Unknown (119)
>>> Unknown (252)
>>> MSZ (57), length 2: 1500
>>> Client-ID (61), length 7: ether 58:d3:49:e7:ca:37
>>> Requested-IP (50), length 4: 192.168.6.240
>>> Lease-Time (51), length 4: 7776000
>>> Hostname (12), length 13: "Living-Room-2"
>>> 00:07:34.809455 ac:1f:6b:1d:fb:80 > 58:d3:49:e7:ca:37, ethertype IPv4
>>> (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 192.168.6.1.67 > 192.168.6.240.68: [udp sum ok] BOOTP/DHCP, Reply,
>>> length 300, xid 0x27e24d21, Flags [none] (0x0000)
>>> Your-IP 192.168.6.240
>>> Client-Ethernet-Address 58:d3:49:e7:ca:37
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: ACK
>>> Server-ID (54), length 4: 192.168.6.1
>>> Lease-Time (51), length 4: 43200
>>> Subnet-Mask (1), length 4: 255.255.255.0
>>> Default-Gateway (3), length 4: 192.168.6.1
>>> Domain-Name-Server (6), length 4: 192.168.6.1
>>> Domain-Name (15), length 21: "redfish-solutions.com"
>>> 00:07:40.513058 9c:3e:53:09:d1:c5 > ff:ff:ff:ff:ff:ff, ethertype IPv4
>>> (0x0800), length 342: (tos 0x0, ttl 255, id 22195, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from
>>> 9c:3e:53:09:d1:c5, length 300, xid 0x87ec8a55, Flags [none] (0x0000)
>>> Client-Ethernet-Address 9c:3e:53:09:d1:c5
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: Request
>>> Parameter-Request (55), length 9: Subnet-Mask (1),
>>> Classless-Static-Route (121), Default-Gateway (3), Domain-Name-Server (6)
>>> Domain-Name (15), Unknown (108), URL (114), Unknown (119)
>>> Unknown (252)
>>> MSZ (57), length 2: 1500
>>> Client-ID (61), length 7: ether 9c:3e:53:09:d1:c5
>>> Requested-IP (50), length 4: 192.168.6.242
>>> Lease-Time (51), length 4: 7776000
>>> Hostname (12), length 11: "Penthouse-6"
>>> 00:07:40.513486 ac:1f:6b:1d:fb:80 > 9c:3e:53:09:d1:c5, ethertype IPv4
>>> (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none],
>>> proto UDP (17), length 328)
>>> 192.168.6.1.67 > 192.168.6.242.68: [udp sum ok] BOOTP/DHCP, Reply,
>>> length 300, xid 0x87ec8a55, Flags [none] (0x0000)
>>> Your-IP 192.168.6.242
>>> Client-Ethernet-Address 9c:3e:53:09:d1:c5
>>> Vendor-rfc1048 Extensions
>>> Magic Cookie 0x63825363
>>> DHCP-Message (53), length 1: ACK
>>> Server-ID (54), length 4: 192.168.6.1
>>> Lease-Time (51), length 4: 43200
>>> Subnet-Mask (1), length 4: 255.255.255.0
>>> Default-Gateway (3), length 4: 192.168.6.1
>>> Domain-Name-Server (6), length 4: 192.168.6.1
>>> Domain-Name (15), length 21: "redfish-solutions.com?
>>> And this repeats every 15-30 seconds. It?s filling up my firewall logs.
>>> The older Apple TV?s (the HD, not 4K ones) don?t do this. Yes, all the
>>> devices are running current firmware.
>>> Anyone else ever seen this?
>>> Thanks
>>> --
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>>> Contact us at https://www.isc.org/contact/ for more information.
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>>> dhcp-users@lists.isc.org
>>> https://lists.isc.org/mailman/listinfo/dhcp-users
> --
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> Contact us at https://www.isc.org/contact/ for more information.
>
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