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<p>Razvan,</p>
<p>The secondary kea server is on a completely seperate computer. My
home network infrastructure consists of on decent (ish) server and
several, old, second hand computers I bought cheap. One of these
runs the secondary server. It binds to the standard ethernet port
of that machine and then services the network via the router. As I
said the main server is connected to the router through br0. It
connects to the internet and to other computers on the network
(e.g. it shares files via samba). It even contacts the secondary
dhcp server to ask it to turn off when I restart kea-dhcp4-server.
It then just doesn't offer leases. The VMs connect to the router
via the Bridged Network and then receive dhcp DORA from the
secondary server via the router, so long as the main server is off
and failover is complete.</p>
<p>There are no files at all in /var/log/kea. There is also no fles
called kea-dhcp4.log in /var/log, where the config file indicates
it should be. I think my logging parameters are screwed up,
perhaps I need to change the debug level or severity, perhaps
there is a stupid typo.</p>
<p>Regards</p>
<p>Stuart MacGregor</p>
<div class="moz-cite-prefix">On 21/2/26 20:10, Razvan Becheriu
wrote:<br>
</div>
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cite="mid:676797738.220027.1771668622505.JavaMail.zimbra@isc.org">
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<div>Hi,</div>
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<div
style="font-size: 12pt; font-family: arial, helvetica, sans-serif; color: #000000;"
data-attr="forced_root_block_attrs">How is it that the vms
acquire ip using secondary server? does the secondary bind on
the same interface at the same time?</div>
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<div
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data-attr="forced_root_block_attrs">Logs should be under
/kea/install/path/var/log/kea</div>
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<div
style="font-size: 12pt; font-family: arial, helvetica, sans-serif; color: #000000;"
data-attr="forced_root_block_attrs">I think that only one of
your servers successfully binds to the interface and because
the server uses reuse port/address the secondary if starts
second will receive traffic.</div>
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<hr id="MESSAGE_DATA_MARKER"><strong>From: </strong>Stuart
<a class="moz-txt-link-rfc2396E" href="mailto:sleepygriogar@gmail.com"><sleepygriogar@gmail.com></a><br>
<strong>To: </strong>kea-users
<a class="moz-txt-link-rfc2396E" href="mailto:kea-users@lists.isc.org"><kea-users@lists.isc.org></a><br>
<strong>Date: </strong>Saturday, 21 February 2026 3:31
AM EET<br>
<strong>Subject: </strong>[Kea-users] Kea DHCP4 not
working on newly configured bridged network<br>
<br>
<p>Good Morning,</p>
<p>I am running Ubuntu 24.04, Kea 2.4.1. I have been
using Kea without major issues for a year or two,
isc-dhcp for a couple of years prior. During recent
kernel updates I decided I was sick of Virtualbox
compatibility issues, so I created a bridged network
so that I could move my vms (Nextcloud, Stork) to KVM.
I am somewhat incompetent, but after about 100
attempts I have managed to setup a bridged network
that connects my server to the rest of the network and
to the internet. My new KVM VMs are joining the
network as if they were real devices. My problem is my
kea DHCP4 server. I guess have done something stupid,
either with selecting the interface in kea-dhcp4.conf
or with configuring my bridged network (br0). At this
stage, when I start kea-dhcp4-server, it communicates
to my HA standby to to take control of DHCP but then
completely fails to provide ip addresses itself. So,
the network currently looks like this:</p>
<p><i>dad@<a class="moz-txt-link-freetext" href="macserver:~$">macserver:~$</a> ip a<br>
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc
noqueue state UNKNOWN group default qlen 1000<br>
link/loopback 00:00:00:00:00:00 brd
00:00:00:00:00:00<br>
inet 127.0.0.1/8 scope host lo<br>
valid_lft forever preferred_lft forever<br>
inet6 ::1/128 scope host noprefixroute <br>
valid_lft forever preferred_lft forever<br>
2: enp34s0: <BROADCAST,MULTICAST,UP,LOWER_UP>
mtu 1500 qdisc fq_codel master br0 state UP group
default qlen 1000<br>
link/ether 2c:<a class="moz-txt-link-freetext" href="f0:5d:2d:88:35">f0:5d:2d:88:35</a> brd
<a class="moz-txt-link-freetext" href="ff:ff:ff:ff:ff:ff">ff:ff:ff:ff:ff:ff</a><br>
3: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu
1500 qdisc noqueue state UP group default qlen 1000<br>
link/ether 42:4c:23:6c:4d:7f brd
<a class="moz-txt-link-freetext" href="ff:ff:ff:ff:ff:ff">ff:ff:ff:ff:ff:ff</a><br>
inet 192.168.1.104/23 brd 192.168.1.255 scope
global noprefixroute br0<br>
valid_lft forever preferred_lft forever<br>
inet6 <a class="moz-txt-link-freetext" href="fe80::e54c:73f4:f662:95fb/64">fe80::e54c:73f4:f662:95fb/64</a> scope link
noprefixroute <br>
valid_lft forever preferred_lft forever<br>
4: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP>
mtu 1500 qdisc noqueue state DOWN group default qlen
1000<br>
link/ether 52:54:00:5b:<a class="moz-txt-link-freetext" href="e6:4e">e6:4e</a> brd
<a class="moz-txt-link-freetext" href="ff:ff:ff:ff:ff:ff">ff:ff:ff:ff:ff:ff</a><br>
inet 192.168.100.1/24 brd 192.168.100.255 scope
global virbr0<br>
valid_lft forever preferred_lft forever<br>
5: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP>
mtu 1500 qdisc noqueue master br0 state UNKNOWN
group default qlen 1000<br>
link/ether <a class="moz-txt-link-freetext" href="fe:00:27:dc:06:7e">fe:00:27:dc:06:7e</a> brd
<a class="moz-txt-link-freetext" href="ff:ff:ff:ff:ff:ff">ff:ff:ff:ff:ff:ff</a><br>
inet6 <a class="moz-txt-link-freetext" href="fe80::fc00:27ff:fedc:67e/64">fe80::fc00:27ff:fedc:67e/64</a> scope link <br>
valid_lft forever preferred_lft forever<br>
6: vnet1: <BROADCAST,MULTICAST,UP,LOWER_UP>
mtu 1500 qdisc noqueue master br0 state UNKNOWN
group default qlen 1000<br>
link/ether <a class="moz-txt-link-freetext" href="fe:54:00:80:eb:73">fe:54:00:80:eb:73</a> brd
<a class="moz-txt-link-freetext" href="ff:ff:ff:ff:ff:ff">ff:ff:ff:ff:ff:ff</a><br>
inet6 <a class="moz-txt-link-freetext" href="fe80::fc54:ff:fe80:eb73/64">fe80::fc54:ff:fe80:eb73/64</a> scope link <br>
valid_lft forever preferred_lft forever</i></p>
<p>The key sections (eliminating all my lease
reservations and such) of my dhcp4.conf look like
this:</p>
<p><i>{<br>
"Dhcp4": {<br>
"interfaces-config": {<br>
"interfaces": [ "br0" ]<br>
},<br>
"control-socket": {<br>
"socket-type": "unix",<br>
"socket-name": "/run/kea/kea4-ctrl-socket"<br>
},<br>
"lease-database": {<br>
"type": "memfile",<br>
"lfc-interval": 3600<br>
},<br>
"multi-threading": {<br>
"enable-multi-threading": true,<br>
"thread-pool-size": 2,<br>
"packet-queue-size": 14<br>
},<br>
"client-classes": [<br>
{<br>
"name": "homeauto"<br>
},<br>
{<br>
"name": "normal",<br>
"test": "not member('homeauto')"<br>
}<br>
],<br>
"option-data": [<br>
{<br>
"space": "dhcp4",<br>
"name": "domain-name",<br>
"code": 15,<br>
"data": "skfaf.servesarcasm.com"<br>
},<br>
{<br>
"space": "dhcp4",<br>
"name": "domain-name-servers",<br>
"code": 6,<br>
"data": "192.168.1.1"<br>
},<br>
{<br>
"space": "dhcp4",<br>
"name": "broadcast-address",<br>
"code": 28,<br>
"data": "192.168.1.255"<br>
},<br>
{<br>
"space": "dhcp4",<br>
"name": "routers",<br>
"code": 3,<br>
"data": "192.168.1.1"<br>
},<br>
{<br>
"space": "dhcp4",<br>
"name": "subnet-mask",<br>
"code": 1,<br>
"data": "255.255.254.0"<br>
}<br>
],<br>
"valid-lifetime": 43200,<br>
"renew-timer": 21600,<br>
"rebind-timer": 32400,<br>
"expired-leases-processing": {<br>
"reclaim-timer-wait-time": 3600,<br>
"hold-reclaimed-time": 172800,<br>
"max-reclaim-leases": 0,<br>
"max-reclaim-time": 0<br>
}, <br>
"dhcp-ddns": {<br>
"enable-updates": false<br>
},<br>
"authoritative": true,<br>
"hooks-libraries": [<br>
{<br>
"library":
"/usr/lib/x86_64-linux-gnu/kea/hooks/libdhcp_lease_cmds.so"<br>
},<br>
{<br>
"library":
"/usr/lib/x86_64-linux-gnu/kea/hooks/libdhcp_stat_cmds.so"<br>
},<br>
{<br>
"library":
"/usr/lib/x86_64-linux-gnu/kea/hooks/libdhcp_ha.so",<br>
"parameters": {<br>
"high-availability": [ {<br>
"this-server-name": "macserver",<br>
"mode": "hot-standby",<br>
"heatbeat-delay": 10000,<br>
"max-response-delay": 60000,<br>
"max-ack-delay": 5000,<br>
"max-unacked-clients": 5,<br>
"sync-timeout": 60000,<br>
"multi-threading": {<br>
"enable-multi-threading": true,<br>
"http-dedicated-listener": true,<br>
"http-listener-threads": 0,<br>
"http-client-threads": 0<br>
},<br>
"peers": [<br>
{<br>
"name": "macserver",<br>
"url": <a
href="http://192.168.1.104:8003/" target="_blank"
rel="noopener noreferrer" moz-do-not-send="true">"http://192.168.1.104:8003/"</a>,<br>
"role": "primary"<br>
},<br>
{ <br>
"name": "oldhp",<br>
"url": <a
href="http://192.168.1.110:8003/" target="_blank"
rel="noopener noreferrer" moz-do-not-send="true">"http://192.168.1.110:8003/"</a>,<br>
"role": "standby"<br>
}<br>
]<br>
} ]<br>
}<br>
}</i></p>
<p><i> </i></p>
<p><i>],<br>
"shared-networks": [<br>
{<br>
"name": "macnet",<br>
"subnet4": [<br>
{<br>
"id": 1,<br>
"subnet": "192.168.1.0/24",<br>
"pools": [<br>
{<br>
"pool": "192.168.1.124 -
192.168.1.198",<br>
"client-class": "normal"<br>
}<br>
],<br>
"option-data": [<br>
{<br>
"space": "dhcp4",<br>
"name": "routers",<br>
"code": 3,<br>
"data": "192.168.1.1"<br>
}<br>
]<br>
},<br>
{<br>
"id": 2,<br>
"subnet": "192.168.0.0/23",<br>
"pools": [<br>
{<br>
"pool": "192.168.0.150 - 192.168.0.175",<br>
"client-class": "homeauto"<br>
}<br>
],<br>
"option-data": [<br>
{<br>
"space": "dhcp4",<br>
"name": "routers",<br>
"code": 3,<br>
"data": "192.168.1.1"<br>
},<br>
{<br>
"space": "dhcp4",<br>
"name": "domain-name-servers",<br>
"code": 6,<br>
"data": "192.168.1.1"<br>
}<br>
]<br>
}<br>
]<br>
}<br>
],<br>
"loggers": [<br>
{<br>
"name": "kea-dhcp4",<br>
"output_options": [<br>
{<br>
"output": "/var/log/kea-dhcp4.log",<br>
"maxsize": 2048000,<br>
"maxver": 4<br>
}<br>
],<br>
"severity": "INFO",<br>
"debuglevel": 0<br>
}<br>
]<br>
}<br>
}</i></p>
<p> </p>
<p>I changed my "interface" to "br0" because my previous
setup (exerp below) stopped working when I started the
br0 network. </p>
<p> <i>{<br>
"Dhcp4": {<br>
"interfaces-config": {<br>
"interfaces": [ "enp34s0" ]</i></p>
<p>Changing the interface to "br0" has had exactly no
effect.</p>
<p>I realise that I have missed something fundamental
and I am wasting your valuable time. However I have
been trying to sort this out for days (in whatever
spare time is available) and I have acheived nothing.
Each time I start kea-dhcp-server on my main server it
appears in Stork with no errors, systemd says its
running fine and my HA standby stops providing dhcp.
Unfortunately if I then turn on a device it simply
does not receive an ip lease. If I turn off DHCP on
the main server then eventually the standby starts
takes over dhcp again and network functions return to
normal (though this takes a very long time &
sometimes requires a restart of kea-dhcp4-server on
the stanby server, perhaps another error to fix
later). Even my new VMs receive ips seamlessly from
the standby server.</p>
<p>If you need to see some logs, please tell me where I
can retreive them because I haven't been able to work
that out either (I think I need to change my logging
parameters in kea-dhcp4.conf). I used Wireshark to
capture network coms before and after turning on the
main dhcp server but I then realised that I was too
stupid/ignorant to work out what was going on from the
output. I can provided the Wireshark output, but it is
a large file (ran it for too long and filtered it
poorly, I think) that I won't inflict on you unless
you wish it.</p>
<p>Please give me some ideas of what I have to do to
troubleshoot/fix this.</p>
<p>Regards</p>
<p>Stuart MacGregor</p>
<p> </p>
<p> </p>
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