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

Dan Oachs doachs at gac.edu
Tue Jan 16 14:58:46 UTC 2024


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....@
> .y..........D.C.4}.....%...........................>...........................................................................................................................................................................................................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....@
> .y..........D.C.4}.....%...........................>...........................................................................................................................................................................................................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....@
> .y..........D.C.4|.....%...........................>...........................................................................................................................................................................................................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....@
> .y..........D.C.4|.....%...........................>...........................................................................................................................................................................................................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|.....%....
> ......................>...........................................................................................................................................................................................................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....@
> .y..........D.C.4.g.....,..........................>...........................................................................................................................................................................................................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
> .
>
>
>
>
>
> 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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> information.
>
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