hi, I have configured a routed network on my laptop with a ipv6 subnet and dnsmasq is handing out ipv6 addresses to my vms and it works really wel, but finding out which ips have been used is not as easy as with ipv4. [root@lenovo ~]# virsh domifaddr --domain wec --source lease  Name       MAC address          Protocol     Address ------------------------------------------------------------------------------- [root@lenovo ~]# virsh domifaddr --domain wec --source arp  Name       MAC address          Protocol     Address ------------------------------------------------------------------------------- When using a ipv4 network, this works: root@lenovo ~]# virsh domifaddr --domain evenng --source arp  Name       MAC address          Protocol     Address -------------------------------------------------------------------------------  vnet2      52:54:00:4c:83:98    ipv4         192.168.122.229/0 <http://192.168.122.229/0> [root@lenovo ~]# virsh domifaddr --domain evenng --source lease  Name       MAC address          Protocol     Address -------------------------------------------------------------------------------  vnet2      52:54:00:4c:83:98    ipv4         192.168.122.229/24 <http://192.168.122.229/24> I can obviously look into the leases file and find out the address, but it would be nice to be able to use the virt tooling.

This is on a fedora 37 running qemu-kvm-7.0.0-14.fc37.x86_64 and dnsmasq-2.89-1.fc37.x86_64, everything intalled from the fedora repositories.

hi, On Tue, Mar 21, 2023 at 3:40 PM Michal Prívozník <mprivozn(a)redhat.com <mailto:mprivozn@redhat.com>> wrote: On 3/19/23 20:21, Natxo Asenjo wrote: > hi, > > I have configured a routed network on my laptop with a ipv6 subnet and > dnsmasq is handing out ipv6 addresses to my vms and it works really wel, > but finding out which ips have been used is not as easy as with ipv4. > > [root@lenovo ~]# virsh domifaddr --domain wec --source lease >  Name       MAC address          Protocol     Address > ------------------------------------------------------------------------------- > > [root@lenovo ~]# virsh domifaddr --domain wec --source arp >  Name       MAC address          Protocol     Address > ------------------------------------------------------------------------------- > > When using a ipv4 network, this works: > > root@lenovo ~]# virsh domifaddr --domain evenng --source arp >  Name       MAC address          Protocol     Address > ------------------------------------------------------------------------------- >  vnet2      52:54:00:4c:83:98    ipv4         192.168.122.229/0 <http://192.168.122.229/0> > <http://192.168.122.229/0 <http://192.168.122.229/0>> > > [root@lenovo ~]# virsh domifaddr --domain evenng --source lease >  Name       MAC address          Protocol     Address > ------------------------------------------------------------------------------- >  vnet2      52:54:00:4c:83:98    ipv4         192.168.122.229/24 <http://192.168.122.229/24> > <http://192.168.122.229/24 <http://192.168.122.229/24>> > > I can obviously look into the leases file and find out the address, but > it would be nice to be able to use the virt tooling. Looks like you won't find any info for IPv6 there, because that's exactly what '--source lease' is doing. Are you sure that your IPv6 address is not autoconfigured and it indeed is libvirt spawned dnsmasq that's assigning the IPv6 address? this is the xml: # cat networks/ipv6.xml <!-- WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE OVERWRITTEN AND LOST. Changes to this xml configuration should be made using:   virsh net-edit ipv6 or other application using the libvirt API. --> <network>   <name>ipv6</name>   <uuid>49957183-e4e4-4541-8746-11be67f0a511</uuid>   <forward mode='open'/>   <bridge name='virbr1' stp='on' delay='0'/>   <mac address='52:54:00:09:8e:66'/>   <domain name='ipv6'/>   <ip family='ipv6' address='2a02:xxx:xx:7::1' prefix='64'>     <dhcp>       <range start='2a02:xxx:xx:7::100' end='2a02:xxx:xx:7::1ff'/>     </dhcp>   </ip> </network> so it looks like a dhcp server to me ;-)

I just found out about virsh net-dhcp-leases and that one lists the leases: # virsh net-dhcp-leases --network ipv6  Expiry Time           MAC address         Protocol   IP address                Hostname          Client ID or DUID ---------------------------------------------------------------------------------------------------------------------------------------------  2023-03-22 16:35:44   52:54:00:0e:ee:da   ipv6       2a02:xxx:xx:7::1ba/64   WIN-C0HD8RH61MI   00:01:00:01:2b:a7:05:c5:52:54:00:0e:ee:da

For the '--source arp' case - libvirt reads the arp table (effectively the same info is exposed under /proc/net/arp file) and finds a matching entry there, based on the MAC address. Can you see whether there's a match? No, that only entry right now there is my router: ]# cat /proc/net/arp IP address       HW type     Flags       HW address            Mask     Device xx.x.x.1         0x1         0x2         cafebabecafe     *        wifi0

And lastly - there's '--source agent' which is most likely to return useful information, but that requires guest agent running inside. Indeed, no agent running on the vm, could add it.