[Kea-users] Kea DDNS issues

Thu Apr 30 07:57:49 UTC 2020

Hi Joshua,

Thank you for the response.
I may be wrong, but I would expect that listening on 127.0.0.1 should work
as it is the server itself.
In fact, the documentation includes a warning for any other configuration:
https://kea.readthedocs.io/en/kea-1.6.1/arm/ddns.html#global-server-parameters
In any case, I changed it to the static Docker network IP 172.16.100.4 and
restarted it.
I note that upon startup now the following warning appears:
2020-04-30 07:35:29.317 INFO  [kea-dhcp-ddns.dctl/1] DCTL_CONFIG_COMPLETE
server has completed configuration: listening on 172.16.100.4, port 53001,
using UDP
2020-04-30 07:35:29.319 WARN  [kea-dhcp-ddns.dhcpddns/1]
DHCP_DDNS_NOT_ON_LOOPBACK the DHCP-DDNS server has been configured to
listen on 172.16.100.4 which is not the local loopback.  This is an
insecure configuration supported for testing purposes only

Following your suggesting I installed ss (iproute2). Oddly enough, it does
not seem to be listening to any ports.
root@ a987aac4aa8b:/# ss
Netid             State             Recv-Q             Send-Q
          Local Address:Port                         Peer Address:Port

One may wonder if kea-dhcp-ddns is really running.
I don't have ps available in the container, but if I try to run it again
manually I naturally get the following:
root at a987aac4aa8b:/# /usr/sbin/kea-dhcp-ddns -c /etc/kea/kea-dhcp-ddns.conf
2020-04-30 07:34:00.521 FATAL [kea-dhcp-ddns.dctl/14] DCTL_ALREADY_RUNNING
kea-dhcp-ddns already running? Daemon::createPIDFile: PID: 1 exists, PID
file: /var/run/kea/kea-dhcp-ddns.kea-dhcp-ddns.pid
Service failed: Launch Failed: Daemon::createPIDFile: PID: 1 exists, PID
file: /var/run/kea/kea-dhcp-ddns.kea-dhcp-ddns.pid
root at a987aac4aa8b:/#

Any idea why it is not listening for connections?
For reference, here are the debug logs:
2020-04-30 07:35:29.313 DEBUG [kea-dhcp-ddns.dhcpddns/1]
DHCP_DDNS_CONFIGURE configuration update received: { "control-socket": {
"socket-name": "/tmp/kea-dhcp-ddns-ctrl.sock", "socket-type": "unix" },
"forward-ddns": { "ddns-domains": [ { "dns-servers": [ { "ip-address":
"172.16.100.1" }, { "ip-address": "172.16.100.2" } ], "key-name":
"rndc-key", "name": "dono.local." } ] }, "ip-address": "172.16.100.4",
"loggers": [ { "debuglevel": 99, "name": "kea-dhcp-ddns", "output_options":
[ { "flush": true, "maxsize": 1048576, "maxver": 3, "output":
"/etc/kea/kea-ddns.log" } ], "severity": "DEBUG" } ], "port": 53001,
"reverse-ddns": { "ddns-domains": [ { "dns-servers": [ { "ip-address":
"172.16.100.1" }, { "ip-address": "172.16.100.2" } ], "key-name":
"rndc-key", "name": "10.10.10.in-addr.arpa." }, { "dns-servers": [ {
"ip-address": "172.16.100.1" }, { "ip-address": "172.16.100.2" } ],
"key-name": "rndc-key", "name": "20.10.10.in-addr.arpa." }, {
"dns-servers": [ { "ip-address": "172.16.100.1" }, { "ip-address":
"172.16.100.2" } ], "key-name": "rndc-key", "name":
"40.10.10.in-addr.arpa." } ] }, "tsig-keys": [ { "algorithm":
"hmac-sha256", "name": "rndc-key", "secret": "<secret>" } ] }
2020-04-30 07:35:29.313 DEBUG [kea-dhcp-ddns.dctl/1] DCTL_CONFIG_START
parsing new configuration: { "control-socket": { "socket-name":
"/tmp/kea-dhcp-ddns-ctrl.sock", "socket-type": "unix" }, "forward-ddns": {
"ddns-domains": [ { "dns-servers": [ { "ip-address": "172.16.100.1" }, {
"ip-address": "172.16.100.2" } ], "key-name": "rndc-key", "name":
"dono.local." } ] }, "ip-address": "172.16.100.4", "loggers": [ {
"debuglevel": 99, "name": "kea-dhcp-ddns", "output_options": [ { "flush":
true, "maxsize": 1048576, "maxver": 3, "output": "/etc/kea/kea-ddns.log" }
], "severity": "DEBUG" } ], "port": 53001, "reverse-ddns": {
"ddns-domains": [ { "dns-servers": [ { "ip-address": "172.16.100.1" }, {
"ip-address": "172.16.100.2" } ], "key-name": "rndc-key", "name":
"10.10.10.in-addr.arpa." }, { "dns-servers": [ { "ip-address":
"172.16.100.1" }, { "ip-address": "172.16.100.2" } ], "key-name":
"rndc-key", "name": "20.10.10.in-addr.arpa." }, { "dns-servers": [ {
"ip-address": "172.16.100.1" }, { "ip-address": "172.16.100.2" } ],
"key-name": "rndc-key", "name": "40.10.10.in-addr.arpa." } ] },
"tsig-keys": [ { "algorithm": "hmac-sha256", "name": "rndc-key", "secret":
"<secret>" } ] }
2020-04-30 07:35:29.315 INFO  [kea-dhcp-ddns.commands/1]
COMMAND_ACCEPTOR_START Starting to accept connections via unix domain
socket bound to /tmp/kea-dhcp-ddns-ctrl.sock
2020-04-30 07:35:29.317 INFO  [kea-dhcp-ddns.dctl/1] DCTL_CONFIG_COMPLETE
server has completed configuration: listening on 172.16.100.4, port 53001,
using UDP
2020-04-30 07:35:29.317 DEBUG [kea-dhcp-ddns.dctl/1] DCTL_RUN_PROCESS
DhcpDdns starting application event loop
2020-04-30 07:35:29.318 INFO  [kea-dhcp-ddns.dhcpddns/1] DHCP_DDNS_STARTED
Kea DHCP-DDNS server version 1.6.2 started
2020-04-30 07:35:29.318 DEBUG [kea-dhcp-ddns.commands/1] COMMAND_REGISTERED
Command build-report registered
2020-04-30 07:35:29.318 DEBUG [kea-dhcp-ddns.commands/1] COMMAND_REGISTERED
Command config-get registered
2020-04-30 07:35:29.318 DEBUG [kea-dhcp-ddns.commands/1] COMMAND_REGISTERED
Command config-reload registered
2020-04-30 07:35:29.318 DEBUG [kea-dhcp-ddns.commands/1] COMMAND_REGISTERED
Command config-set registered
2020-04-30 07:35:29.318 DEBUG [kea-dhcp-ddns.commands/1] COMMAND_REGISTERED
Command config-test registered
2020-04-30 07:35:29.318 DEBUG [kea-dhcp-ddns.commands/1] COMMAND_REGISTERED
Command config-write registered
2020-04-30 07:35:29.318 DEBUG [kea-dhcp-ddns.commands/1] COMMAND_REGISTERED
Command shutdown registered
2020-04-30 07:35:29.318 DEBUG [kea-dhcp-ddns.commands/1] COMMAND_REGISTERED
Command version-get registered
2020-04-30 07:35:29.318 DEBUG [kea-dhcp-ddns.dhcpddns/1]
DHCP_DDNS_QUEUE_MGR_RECONFIGURING application is reconfiguring the queue
manager
2020-04-30 07:35:29.319 WARN  [kea-dhcp-ddns.dhcpddns/1]
DHCP_DDNS_NOT_ON_LOOPBACK the DHCP-DDNS server has been configured to
listen on 172.16.100.4 which is not the local loopback.  This is an
insecure configuration supported for testing purposes only
2020-04-30 07:35:29.319 DEBUG [kea-dhcp-ddns.dhcpddns/1]
DHCP_DDNS_QUEUE_MGR_STARTED application's queue manager has begun listening
for requests.

And here are interface details from within the container:
root at a987aac4aa8b:/# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group
default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
287: eth0 at if288: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue
state UP group default
    link/ether 02:42:ac:10:64:04 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 172.16.100.4/24 brd 172.16.100.255 scope global eth0
       valid_lft forever preferred_lft forever

Regards,
Ben Monroe

On Thu, Apr 30, 2020 at 2:30 PM Joshua Schaeffer <jschaeffer at harmonywave.com>
wrote:

> You are sending to 172.16.100.4 from the DHCP4 server, but listening on
> localhost on the DDNS server:
>
> On 4/29/20 9:45 PM, Ben Monroe wrote:
>
>     "dhcp-ddns": {
>       "enable-updates": true,
>       "qualifying-suffix": "dono.local.",
>       "server-ip": "172.16.100.4"
>
>
> And in kea-dhcp-ddns.conf I have:
> {
> "DhcpDdns":
> {
>   "ip-address": "127.0.0.1",
>   "port": 53001,
>
> You need to listen on your global IP address. Use ss or netstat (if you
> have them available in your container) to confirm which interface D2 is
> actually listening on.
>
> --
> Thanks,
> Joshua Schaeffer
>
>
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