[Kea-users] dhcp4 server stops responding to a device

Gavin Davenport gavdav at gavdav.net
Fri Jan 19 13:37:04 UTC 2024


Does anyone have any idea why dhcp would not actually emit the dhcp response following logging
2024-01-19 13:35:02.390 INFO  [kea-dhcp4.leases/855.139674733151936] DHCP4_LEASE_ADVERT [hwtype=1 fc:fe:c2:05:3e:b7], cid=[no info], tid=0xf3db5a1f: lease 10.99.99.3 will be advertised
2024-01-19 13:35:17.539 INFO  [kea-dhcp4.leases/855.139674758330048] DHCP4_LEASE_ADVERT [hwtype=1 fc:fe:c2:05:3e:b7], cid=[no info], tid=0xf3db5a1f: lease 10.99.99.3 will be advertised
2024-01-19 13:35:32.689 INFO  [kea-dhcp4.leases/855.139674749937344] DHCP4_LEASE_ADVERT [hwtype=1 fc:fe:c2:05:3e:b7], cid=[no info], tid=0xf3db5a1f: lease 10.99.99.3 will be advertised

It's received the discover (visible in tcpdump) but why would it get jammed and refuse to respond to this ?

is there anything I have misconfigured in the scope ? Are there any improved debugging options I might use ?

-----Original Message-----
From: Kea-users <kea-users-bounces at lists.isc.org> On Behalf Of Gavin Davenport
Sent: 16 January 2024 20:46
To: Kea user's list <kea-users at lists.isc.org>
Subject: Re: [Kea-users] dhcp4 server stops responding to a device

I was using isc-dhcp and had this behaviour too:
https://gitlab.isc.org/isc-projects/dhcp/-/issues/177

I switched to kea-dhcp4 and it fixed it.

I've since done a distro upgrade and it's gone flaky again. 

I've no idea how to diagnose signal quality from the data I can get from the wiser (there's a rest endpoint) but this isn't available when it gets unaddressed.

-----Original Message-----
From: Kea-users <kea-users-bounces at lists.isc.org> On Behalf Of Andrew Rowson via Kea-users
Sent: 16 January 2024 18:25
To: kea-users at lists.isc.org
Cc: Andrew Rowson <andrew at growse.com>
Subject: Re: [Kea-users] dhcp4 server stops responding to a device

For what it's worth, I also have a wiser thermostat and hand out a static IP with kea. No issues here.

No bootp as far as I know, and any historical unreliability has been signal-related.

Happy to replicate any tests (dhcpdump etc.) on my sort-of-working environment.

Andrew

On Tue, 16 Jan 2024, at 5:38 PM, Gavin Davenport wrote:
> I wonder, if this was the case, would it work at all ?
>
> This started misbehaving (having worked reliably) on 01/01/2024 – and 
> has been steadily getting more unreliable.
> 
> 
> *From:* Kea-users <kea-users-bounces at lists.isc.org> *On Behalf Of *Dan 
> Oachs
> *Sent:* 16 January 2024 14:59
> *To:* Kea user's list <kea-users at lists.isc.org>
> *Subject:* Re: [Kea-users] dhcp4 server stops responding to a device
> 
> Is that device using BOOTP instead of DHCP by any chance?  If so, you 
> might need the Bootp kea hook library.  But that's just a guess.
> 
> --Dan
> 
> 
> On Tue, Jan 16, 2024 at 6:08 AM Gavin Davenport <gavdav at gavdav.net> wrote:
>> I have a “Wiser smart hub” 
>> https://wiser.draytoncontrols.co.uk/smart-heating-kits
>>  
>> This is basically a central heating timer with a wifi adapter.
>>  
>> I can’t set a static IP on it so it is dependent on working DHCP (and wifi) to stay connected to the network.
>>  
>> I’m seeing the kea-dhcp server not respond to its dhcprequests and restarting the wifi and restarting the dhcp server do not seem to help.
>>  
>> Config file has a reservation for it’s address: (fc:fe:c2:05:3e:b7)
>> 
>> {
>> "Dhcp4": {
>>     "interfaces-config": {
>>         "interfaces": [
>>           "enp2s0"
>>         ]
>>     },
>>  
>>     "control-socket": {
>>         "socket-type": "unix",
>>         "socket-name": "/tmp/kea4-ctrl-socket"
>>     },
>>  
>>     "lease-database": {
>>         "type": "memfile",
>>         "lfc-interval": 3600
>>     },
>>  
>>  
>>     "expired-leases-processing": {
>>         "reclaim-timer-wait-time": 10,
>>         "flush-reclaimed-timer-wait-time": 25,
>>         "hold-reclaimed-time": 3600,
>>         "max-reclaim-leases": 100,
>>         "max-reclaim-time": 250,
>>         "unwarned-reclaim-cycles": 5
>>     },
>>  
>>     "renew-timer": 900,
>>     "rebind-timer": 1800,
>>     "valid-lifetime": 43200,
>>  
>>     "option-data": [
>>         {
>>             "name": "domain-name-servers",
>>             "data": "10.99.99.119, 10.99.99.111"
>>         },
>>         {
>>             "name": "domain-name",
>>             "data": "ad.domain.net"
>>         },
>>         {
>>             "name": "domain-search",
>>             "data": "ad.domain.net, domain.net"
>>         },
>>         {
>>             "name": "default-ip-ttl",
>>             "data": "0xf0"
>>         }
>>     ],
>>  
>>  
>>     "subnet4": [
>>         {
>>             "subnet": "10.99.99.0/24",
>>             "pools": [ { "pool": "10.99.99.2 - 10.99.99.63" } ],
>>             "reservations": [
>>                 {
>>                     "hw-address": "fc:fe:c2:05:3e:b7",
>>                     "ip-address": "10.99.99.3"
>>                 }
>>             ],
>>             "option-data": [
>>                 {
>>                     "name": "routers",
>>                     "data": "10.99.99.1"
>>                 }
>>             ]
>>         }
>>     ],
>>  
>>  
>>     "loggers": [
>>     {
>>         "name": "kea-dhcp4",
>>         "output_options": [
>>             {
>>                 "output": "/var/log/kea-dhcp4.log"
>>             }
>>         ],
>>         "severity": "DEBUG",
>>         "debuglevel": 7
>>     }
>>   ]
>> }
>> }
>>  
>> So I reserve 10.99.99.3 for the wiser device.
>>  
>> For quite long periods of time I get this logged
>> 2024-01-16 11:51:22.170 INFO
>> [kea-dhcp4.leases/1112259.140235902645952] DHCP4_LEASE_ADVERT
>> [hwtype=1 fc:fe:c2:05:3e:b7], cid=[no info], tid=0x25eeba9a: lease
>> 10.99.99.3 will be advertised
>> 2024-01-16 11:51:37.918 INFO
>> [kea-dhcp4.leases/1112259.140235894253248] DHCP4_LEASE_ADVERT
>> [hwtype=1 fc:fe:c2:05:3e:b7], cid=[no info], tid=0x25eeba9a: lease
>> 10.99.99.3 will be advertised
>> 2024-01-16 11:51:53.681 INFO
>> [kea-dhcp4.leases/1112259.140235885860544] DHCP4_LEASE_ADVERT
>> [hwtype=1 fc:fe:c2:05:3e:b7], cid=[no info], tid=0x25eeba9a: lease
>> 10.99.99.3 will be advertised
>> 2024-01-16 11:52:04.033 INFO
>> [kea-dhcp4.leases/1112259.140235911038656] DHCP4_LEASE_ADVERT
>> [hwtype=1 fc:fe:c2:05:3e:b7], cid=[no info], tid=0xcf035c28: lease
>> 10.99.99.3 will be advertised
>>  
>> And when I tcpdump I see this (tcpdump -v -n -A -i enp2s0 ether host
>> fc:fe:c2:05:3e:b7)
>>  
>> 11:50:49.034748 IP (tos 0x0, ttl 64, id 17, offset 0, flags [none], proto UDP (17), length 328)
>>     0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fc:fe:c2:05:3e:b7, length 300, xid 0x25eeba9a, secs 224, Flags [Broadcast]
>>           Client-Ethernet-Address fc:fe:c2:05:3e:b7
>>           Vendor-rfc1048 Extensions
>>             Magic Cookie 0x63825363
>>             DHCP-Message (53), length 1: Discover
>>             Hostname (12), length 15: "WiserHeat053EB7"
>> E..H.... at .y..........D.C.4}.....%...........................>...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7 <mailto:E..H.... at .y..........D.C.4%7d.....%25...........................%3e...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7>........................................
>> 11:51:05.598448 IP (tos 0x0, ttl 64, id 18, offset 0, flags [none], proto UDP (17), length 328)
>>     0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fc:fe:c2:05:3e:b7, length 300, xid 0x25eeba9a, secs 240, Flags [Broadcast]
>>           Client-Ethernet-Address fc:fe:c2:05:3e:b7
>>           Vendor-rfc1048 Extensions
>>             Magic Cookie 0x63825363
>>             DHCP-Message (53), length 1: Discover
>>             Hostname (12), length 15: "WiserHeat053EB7"
>> E..H.... at .y..........D.C.4}.....%...........................>...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7 <mailto:E..H.... at .y..........D.C.4%7d.....%25...........................%3e...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7>........................................
>> 11:51:22.169853 IP (tos 0x0, ttl 64, id 19, offset 0, flags [none], proto UDP (17), length 328)
>>     0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fc:fe:c2:05:3e:b7, length 300, xid 0x25eeba9a, secs 257, Flags [Broadcast]
>>           Client-Ethernet-Address fc:fe:c2:05:3e:b7
>>           Vendor-rfc1048 Extensions
>>             Magic Cookie 0x63825363
>>             DHCP-Message (53), length 1: Discover
>>             Hostname (12), length 15: "WiserHeat053EB7"
>> E..H.... at .y..........D.C.4|.....%...........................>...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7 <mailto:E..H.... at .y..........D.C.4|.....%25...........................%3e...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7>........................................
>> 11:51:37.917905 IP (tos 0x0, ttl 64, id 20, offset 0, flags [none], proto UDP (17), length 328)
>>     0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fc:fe:c2:05:3e:b7, length 300, xid 0x25eeba9a, secs 273, Flags [Broadcast]
>>           Client-Ethernet-Address fc:fe:c2:05:3e:b7
>>           Vendor-rfc1048 Extensions
>>             Magic Cookie 0x63825363
>>             DHCP-Message (53), length 1: Discover
>>             Hostname (12), length 15: "WiserHeat053EB7"
>> E..H.... at .y..........D.C.4|.....%...........................>...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7 <mailto:E..H.... at .y..........D.C.4|.....%25...........................%3e...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7>........................................
>> 11:51:53.681500 IP (tos 0x0, ttl 64, id 21, offset 0, flags [none], proto UDP (17), length 328)
>>     0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fc:fe:c2:05:3e:b7, length 300, xid 0x25eeba9a, secs 288, Flags [Broadcast]
>>           Client-Ethernet-Address fc:fe:c2:05:3e:b7
>>           Vendor-rfc1048 Extensions
>>             Magic Cookie 0x63825363
>>             DHCP-Message (53), length 1: Discover
>>             Hostname (12), length 15: "WiserHeat053EB7"
>> E..H.... at .y..........D.C.4|.....% <mailto:E..H.... at .y..........D.C.4|.....%25>.... ......................>...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7........................................
>>  
>> The above shows the wiser device making a request, but does not show 
>> any response from the DHCP server, despite the dhcp server logging “lease 10.99.99.3 will be advertised”
>>  
>> There will be long periods where the DHCP server won’t respond (to 
>> this device, other DHCP clients appear fine), but then it will 
>> abritraily respond and the wiser device will be back on the network 
>> for a while
>>  
>> This is where it actually sends a DHCP request
>> 11:52:39.984714 IP (tos 0x0, ttl 64, id 5, offset 0, flags [none], proto UDP (17), length 328)
>>     0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fc:fe:c2:05:3e:b7, length 300, xid 0x882ceff1, Flags [Broadcast]
>>           Client-Ethernet-Address fc:fe:c2:05:3e:b7
>>           Vendor-rfc1048 Extensions
>>             Magic Cookie 0x63825363
>>             DHCP-Message (53), length 1: Discover
>>             Hostname (12), length 15: "WiserHeat053EB7"
>> E..H.... at .y..........D.C.4.g.....,..........................>...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7 <mailto:E..H.... at .y..........D.C.4.g.....,..........................%3e...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB7>........................................
>> 11:52:40.194286 IP (tos 0x0, ttl 64, id 6, offset 0, flags [none], proto UDP (17), length 328)
>>     0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fc:fe:c2:05:3e:b7, length 300, xid 0xc5a2f26a, Flags [Broadcast]
>>           Client-Ethernet-Address fc:fe:c2:05:3e:b7
>>           Vendor-rfc1048 Extensions
>>             Magic Cookie 0x63825363
>>             DHCP-Message (53), length 1: Request
>>             Hostname (12), length 15: "WiserHeat053EB7"
>>             Server-ID (54), length 4: 10.99.99.119
>>             Requested-IP (50), length 4: 10.99.99.3
>>             Parameter-Request (55), length 7:
>>               Subnet-Mask (1), Default-Gateway (3), Domain-Name-Server (6), MTU (26)
>>               Lease-Time (51), RN (58), RB (59)
>> E..H.... at .y..........D.C.4.........j........................>...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB76 <mailto:E..H.... at .y..........D.C.4.........j........................%3e...........................................................................................................................................................................................................c.Sc5....WiserHeat053EB76>.
>>  
>>  
>> How do I debug this ? why do I not see the “discover->offer->request->ack” sequence logged by the DHCP server or any of the servers responses in my tcpdump ?
>>  
>> Many thanks
>> --
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