On 3/25/25 9:19 AM, gameplayer2019pl--- via Users wrote:
Hello,
I've recently tried to run KEA DHCP server inside of a Debian VM and the
following host interface configuration, attached to that VM:
```
<network>
<name>netasn-dhcpv6</name>
<bridge name="netasn-dhcpv6" stp="on" delay="0"/>
<mtu size="1500"/>
<mac address="XX:XX:XX:XX:XX:XX"/>
<dns enable="no"/>
<ip family="ipv6" address="2a14:7581:feb::1" prefix="64">
</ip>
</network>
```
But whenever I'm trying to run dhclient on another Debian VM attached to the
same network I couldn't obtain the IPv6 lease from KEA DHCP.
The host is as well running Debian, 12 version.
Is there anyway to make the DHCP work from Guest VM instead of using built-in
libvirt DHCP?
I haven't tried it with IPv6 (and not even with IPv4 in a very long
time), but as long as you don't have a <dhcp> section under your <ip>,
libvirt shouldn't be starting its own dhcp server on the bridge (and
since you have <dns enable='no'/> it shouldn't start up dnsmasq at all).
I suppose it *might* have something to do with the firewall rules added
for the particular type of network - since you have no <forward>
element, that network will be an "isolated" network, and will have
firewall rules added to prevent any traffic from traveling beyond that
bridge device / subnet; this shouldn't affect communications between two
guests connected to the same network though. If you want to test that
theory, add <forward mode='open'/> to the network definition and restart
it (then shutdown/restart both of your guests) - this will assure that
no firewall rules will be added for the network.
You may also want to doublecheck any firewall rules on the guest that's
running the DHCP server. Oh, and also try offering IPv4 IPs and see if
the other guest gets an IPv4 address but not IPv6.
