[Kea-users] Support for dual stack DDNS

Joshua Schaeffer jschaeffer at harmonywave.com
Sat May 25 17:11:07 UTC 2019


*tl;dr*

Are dual stack DDNS updates supported in Kea 1.5.0? It looks like it's not. Is section 12.1.3 of the documentation still accurate [1]? Everything works great on the IPv6 side but I can't get IPv4 working. My DHCPv4 requests use the same DUID as my DHCPv6 requests in accordance with RFC 4703. It looks like Kea recognizes that it needs to create a NCR but doesn't actually create it.

-------------------------------
I turned on debugging and then tested with a client machine. In the kea-dhcp4.log I found the following near the end of the log:

2019-05-25 10:42:52.515 DEBUG [kea-dhcp4.ddns/11575] DHCP4_NCR_CREATE [hwtype=1 52:54:00:f1:bf:31], cid=[ff:00:f1:bf:31:00:01:00:01:24:76:e0:6d:52:54:00:f1:bf:31], tid=0x383b9c49: DDNS updates enabled, therefore sending name change requests

However, looking at the kea-dhcp-ddns.log file I only see the request for IPv6 (which happens first; a few seconds prior). You can see in the DHCPv4 log that it thinks about sending the NCR around 10:42:52, but there isn't anything in the DDNS log after 10:42:47.

2019-05-25 10:42:47.028 DEBUG [kea-dhcp-ddns.dhcp-to-d2/11589] DHCP_DDNS_QUEUE_MGR_QUEUE_RECEIVE Request ID 000201458631342F827321C9B541474E0309D6519C1C6B05D40C64F7072F46A019280E: received and queued a request.
2019-05-25 10:42:47.029 DEBUG [kea-dhcp-ddns.d2-to-dns/11589] DHCP_DDNS_STARTING_TRANSACTION Request ID 000201458631342F827321C9B541474E0309D6519C1C6B05D40C64F7072F46A019280E:
2019-05-25 10:42:47.030 DEBUG [kea-dhcp-ddns.d2-to-dns/11589] DHCP_DDNS_UPDATE_REQUEST_SENT Request ID 000201458631342F827321C9B541474E0309D6519C1C6B05D40C64F7072F46A019280E: Forward Add to server: 2620:5:e000::a1 port:53
2019-05-25 10:42:47.041 DEBUG [kea-dhcp-ddns.asiodns/11589] ASIODNS_FETCH_COMPLETED upstream fetch to 2620:5:e000::a1(53) has now completed
2019-05-25 10:42:47.042 DEBUG [kea-dhcp-ddns.d2-to-dns/11589] DHCP_DDNS_UPDATE_RESPONSE_RECEIVED Request ID 000201458631342F827321C9B541474E0309D6519C1C6B05D40C64F7072F46A019280E: to server: 2620:5:e000::a1 port:53 status: SUCCESS, rcode: NOERROR
2019-05-25 10:42:47.042 DEBUG [kea-dhcp-ddns.d2-to-dns/11589] DHCP_DDNS_UPDATE_REQUEST_SENT Request ID 000201458631342F827321C9B541474E0309D6519C1C6B05D40C64F7072F46A019280E: Reverse Replace to server: 2620:5:e000::a1 port:53
2019-05-25 10:42:47.052 DEBUG [kea-dhcp-ddns.asiodns/11589] ASIODNS_FETCH_COMPLETED upstream fetch to 2620:5:e000::a1(53) has now completed
2019-05-25 10:42:47.053 DEBUG [kea-dhcp-ddns.d2-to-dns/11589] DHCP_DDNS_UPDATE_RESPONSE_RECEIVED Request ID 000201458631342F827321C9B541474E0309D6519C1C6B05D40C64F7072F46A019280E: to server: 2620:5:e000::a1 port:53 status: SUCCESS, rcode: NOERROR
2019-05-25 10:42:47.053 INFO  [kea-dhcp-ddns.d2-to-dns/11589] DHCP_DDNS_ADD_SUCCEEDED DHCP_DDNS Request ID 000201458631342F827321C9B541474E0309D6519C1C6B05D40C64F7072F46A019280E: successfully added the DNS mapping addition for this request: Type: 0 (CHG_ADD)
Forward Change: yes
Reverse Change: yes
FQDN: [bllsplunk01.harmonywave.cloud.]
IP Address: [fd83:ac1:8bef:2054:0:7:1:0]
DHCID: [000201458631342F827321C9B541474E0309D6519C1C6B05D40C64F7072F46A019280E]
Lease Expires On: 19700101000000
Lease Length: 4000

It looks like it successfully adds the IPv6 name change and then never attempts to add the IPv4. I believe I've setup DDNS correctly on both DHCPv4 and v6. Here is my DHCPv4 relevant config sections:

"dhcp-ddns": {
    "enable-updates": true,
    "qualifying-suffix": "harmonywave.cloud.",
    "server-ip": "::1",
    "override-client-update": true,
    "replace-client-name": "when-not-present",
    "hostname-char-set": "[^A-Za-z0-9.-]"
},

And my DDNS config:

{
    "ip-address": "::1",
    "port": 53001,
    [...]
    "forward-ddns" : {
        "ddns-domains": [
            {
                "name": "harmonywave.cloud.",
                "key-name": "...",
                "dns-servers": [ { "ip-address": "2620:5:e000::a1" } ]
            }
        ]
    },
    "reverse-ddns" : {
        "ddns-domains": [
            {
                "name": "0.0.0.e.5.0.0.0.0.2.6.2.ip6.arpa.",
                "key-name": "...",
                "dns-servers": [ { "ip-address": "2620:5:e000::a1" } ]
            },
            {
                "name": "f.e.b.8.1.c.a.0.3.8.d.f.ip6.arpa.",
                "key-name": "...",
                "dns-servers": [ { "ip-address": "2620:5:e000::a1" } ]
            },
            {
                "name": "2.10.in-addr.arpa.",
                "key-name": "...",
                "dns-servers": [ { "ip-address": "192.41.41.43" } ]
            }
        ]
    }
},

Are there any plans to implement this?

[1] https://ftp.isc.org/isc/kea/cur/doc/kea-guide.html#dhcp-ddns-dual-stack

-- 
Thanks,
Joshua Schaeffer




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