[Kea-users] Doubled and tripled domain

Thomas Markwalder tmark at isc.org
Mon Mar 19 16:03:53 UTC 2018


Hello Sebastian:

Kea is taking the hostname it received in the DISCOVER and appending the 
qualifying suffix to it to use as the hostname sent back in the OFFER.  
The client is then combining that hostname with the domain-name option 
from the offer and using that to form the FQDN option it sends in the 
REQUEST.  If your clients reliably constructing the FQDN from the 
hostname plus the domain-name then you should be able to set 
qualifying-suffix to "".


Regards,

Thomas

On 03/19/2018 11:30 AM, Zayer, Sebastian wrote:
>
> Hey there,
>
> we are experiencing some issues on some of our devices regarding the 
> domainpart. It’s doubled or tripled (like 
> device.example.org.example.org or 
> device.example.org.example.org.example.org) which is not just annoying 
> but also relevant to the dns.
>
> The main part of the network is Microsoft-based (AD, AD-DNS, 
> Authentication, …).
>
> Can anybody tell me, where the problem is?
>
> The interesting part of the configuration looks like the following:
>
> --kea-dhcp4.conf start--
>
> “Dhcp4”: {
>
>     “dhcp-ddns”: {
>
>       “enabled-updates”: true,
>
>       “qualifying-suffix”: , “example.com.”
>
>       “replace-client-name”: “never”,
>
>       “generated-prefix”: “noname”
>
>     },
>
>     “option-data”: [
>
>     {
>
>       “code”: 15,
>
>       “name”: “domain-name”,
>
>       “data”: “example.com”
>
>     },
>
>     {
>
>       “name”: “domain-search”,
>
>       “data”: “example.com”
>
>     }
>
>     ]
>
>>
> --kea-dhcp4.conf end—
>
> In the logs we see the following (1 example, DEBUG 99):
>
> DEBUG [kea-dhcp4.packets] DHCP4_PACKET_RECEIVED [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: 
> DHCPDISCOVER (type 1) received from 10.36.9.97 to 192.168.100.114 on 
> interface ens192
>
> DEBUG [kea-dhcp4.packets] DHCP4_QUERY_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003, packet 
> details: local_address=192.168.100.114:67, 
> remote_address=10.36.9.97:67, msg_type=DHCPDISCOVER (1), 
> transid=0xf2110003,#012options:#012 type=012, len=010: 
> "printerdevice" (string)#012  type=050, len=004: 10.36.9.104 
> (ipv4-address)#012  type=051, len=004: 4294967295 (uint32)#012  
> type=053, len=001: 1 (uint8)#012 type=055, len=014: 1(uint8) 3(uint8) 
> 42(uint8) 4(uint8) 6(uint8) 12(uint8) 15(uint8) 26(uint8) 44(uint8) 
> 51(uint8) 54(uint8) 58(uint8) 59(uint8) 190(uint8)#012  type=060, 
> len=058: "Mfg=LEXMARK;Typ=MFP;Mod=Lexmark 
> MX310dn;Ser=<serialnr>;" (string)#012 type=061, len=007: 
> 01:00:21:b7:f3:d8:20
>
> DEBUG [kea-dhcp4.packets] DHCP4_SUBNET_SELECTED [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: the 
> subnet with ID 4376 was selected for client assignments
>
> DEBUG [kea-dhcp4.packets] DHCP4_SUBNET_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: the 
> selected subnet details: 10.36.9.96/27
>
> DEBUG [kea-dhcp4.dhcp4] DHCP4_CLASS_ASSIGNED [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: client 
> packet has been assigned to the following class(es): 
> VENDOR_CLASS_Mfg=LEXMARK;Typ=MFP;Mod=Lexmark MX310dn;Ser=<serialnr>;
>
> DEBUG [kea-dhcp4.ddns] DHCP4_CLIENT_HOSTNAME_PROCESS [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: 
> processing client's Hostname option
>
> DEBUG [kea-dhcp4.ddns] DHCP4_CLIENT_HOSTNAME_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: client 
> sent Hostname option: printerdevice
>
> DEBUG [kea-dhcp4.ddns] DHCP4_CLIENT_HOSTNAME_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: client 
> sent Hostname option: printerdevice
>
> DEBUG [kea-dhcp4.ddns] DHCP4_RESPONSE_HOSTNAME_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: 
> including Hostname option in the server's response: 
> printerdevice.example.org
>
> DEBUG [kea-dhcp4.alloc-engine] ALLOC_ENGINE_V4_OFFER_EXISTING_LEASE 
> allocation engine will try to offer existing lease to the client 
> [hwtype=1 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003
>
> INFO  [kea-dhcp4.leases] DHCP4_LEASE_ADVERT [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: lease 
> 10.36.9.104 will be advertised
>
> DEBUG [kea-dhcp4.options] DHCP4_PACKET_PACK [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: 
> preparing on-wire format of the packet to be sent
>
> DEBUG [kea-dhcp4.packets] DHCP4_PACKET_SEND [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: trying 
> to send packet DHCPOFFER (type 2) from 192.168.100.114:67 to 
> 10.36.9.97:67 on interface ens192
>
> DEBUG [kea-dhcp4.packets] DHCP4_RESPONSE_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: 
> responding with packet DHCPOFFER (type 2), packet details: 
> local_address=192.168.100.114:67, remote_address=10.36.9.97:67, 
> msg_type=DHCPOFFER (2), transid=0xf2110003,#012options:#012  type=001, 
> len=004: 4294967264 (uint32)#012  type=003, len=004: 10.36.9.97#012 
> type=006, len=008: 192.168.100.15 192.168.100.14#012 type=012, 
> len=020: "printerdevice.example.com" (string)#012 type=042, 
> len=008: 192.168.100.15 192.168.100.14#012 type=044, len=004: 
> 192.168.100.15#012  type=051, len=004: 1209600 (uint32)#012  type=053, 
> len=001: 2 (uint8)#012 type=054, len=004: 192.168.100.114#012  
> type=058, len=004: 604800 (uint32)#012  type=059, len=004: 604800 
> (uint32)#012 type=061, len=007: 01:00:21:b7:f3:d8:20
>
> DEBUG [kea-dhcp4.packets] DHCP4_PACKET_RECEIVED [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: 
> DHCPREQUEST (type 3) received from 10.36.9.97 to 192.168.100.114 on 
> interface ens192
>
> DEBUG [kea-dhcp4.packets] DHCP4_QUERY_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003, packet 
> details: local_address=192.168.100.114:67, 
> remote_address=10.36.9.97:67, msg_type=DHCPREQUEST (3), 
> transid=0xf2110003,#012options:#012  type=012, len=020: 
> "printerdevice.example.com" (string)#012 type=050, len=004: 
> 10.36.9.104 (ipv4-address)#012  type=053, len=001: 3 (uint8)#012  
> type=054, len=004: 192.168.100.114 (ipv4-address)#012  type=055, 
> len=014: 1(uint8) 3(uint8) 42(uint8) 4(uint8) 6(uint8) 12(uint8) 
> 15(uint8) 26(uint8) 44(uint8) 51(uint8) 54(uint8) 58(uint8) 59(uint8) 
> 190(uint8)#012  type=060, len=058: 
> "Mfg=LEXMARK;Typ=MFP;Mod=Lexmark MX310dn;Ser=<serialnr>;" 
> (string)#012 type=061, len=007: 01:00:21:b7:f3:d8:20#012  type=81 
> (CLIENT_FQDN), flags: (N=0, E=0, O=0, S=0), 
> domain-name='printerdevice.example.com.example.com' (partial)
>
> DEBUG [kea-dhcp4.packets] DHCP4_SUBNET_SELECTED [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: the 
> subnet with ID 4376 was selected for client assignments
>
> DEBUG [kea-dhcp4.packets] DHCP4_SUBNET_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: the 
> selected subnet details: 10.36.9.96/27
>
> DEBUG [kea-dhcp4.dhcp4] DHCP4_CLASS_ASSIGNED [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: client 
> packet has been assigned to the following class(es): 
> VENDOR_CLASS_Mfg=LEXMARK;Typ=MFP;Mod=Lexmark MX310dn;Ser=<serialnr>;
>
> DEBUG [kea-dhcp4.ddns] DHCP4_CLIENT_FQDN_PROCESS [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: 
> processing Client FQDN option
>
> DEBUG [kea-dhcp4.ddns] DHCP4_CLIENT_FQDN_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: Client 
> sent FQDN option: type=81 (CLIENT_FQDN), flags: (N=0, E=0, O=0, S=0), 
> domain-name='printerdevice.example.com.example.com' (partial)
>
> DEBUG [kea-dhcp4.ddns] DHCP4_RESPONSE_FQDN_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: 
> including FQDN option in the server's response: type=81 (CLIENT_FQDN), 
> flags: (N=0, E=0, O=0, S=0), 
> domain-name='printerdevice.example.com.example.com.example.com.' (full)
>
> DEBUG [kea-dhcp4.alloc-engine] ALLOC_ENGINE_V4_REQUEST_EXTEND_LEASE 
> [hwtype=1 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], 
> tid=0xf2110003: extending lifetime of the lease for address 10.36.9.104
>
> INFO  [kea-dhcp4.leases] DHCP4_LEASE_ALLOC [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: lease 
> 10.36.9.104 has been allocated
>
> DEBUG [kea-dhcp4.ddns] DHCP4_NCR_CREATE [hwtype=1 00:21:b7:f3:d8:20], 
> cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: DDNS updates enabled, 
> therefore sending name change requests
>
> DEBUG [kea-dhcp4.options] DHCP4_PACKET_PACK [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: 
> preparing on-wire format of the packet to be sent
>
> DEBUG [kea-dhcp4.packets] DHCP4_PACKET_SEND [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: trying 
> to send packet DHCPACK (type 5) from 192.168.100.114:67 to 
> 10.36.9.97:67 on interface ens192
>
> DEBUG [kea-dhcp4.packets] DHCP4_RESPONSE_DATA [hwtype=1 
> 00:21:b7:f3:d8:20], cid=[01:00:21:b7:f3:d8:20], tid=0xf2110003: 
> responding with packet DHCPACK (type 5), packet details: 
> local_address=192.168.100.114:67, remote_address=10.36.9.97:67, 
> msg_type=DHCPACK (5), transid=0xf2110003,#012options:#012  type=001, 
> len=004: 4294967264 (uint32)#012  type=003, len=004: 10.36.9.97#012 
> type=006, len=008: 192.168.100.15 192.168.100.14#012 type=042, 
> len=008: 192.168.100.15 192.168.100.14#012 type=044, len=004: 
> 192.168.100.15#012  type=051, len=004: 1209600 (uint32)#012  type=053, 
> len=001: 5 (uint8)#012 type=054, len=004: 192.168.100.114#012  
> type=058, len=004: 604800 (uint32)#012  type=059, len=004: 604800 
> (uint32)#012  type=061, len=007: 01:00:21:b7:f3:d8:20#012  type=81 
> (CLIENT_FQDN), flags: (N=0, E=0, O=0, S=0), 
> domain-name='printerdevice.example.com.example.com.example.com.' (full)
>
>
>
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