Host: Manjaro, Guest: Artix Linux, Issue: No virtio NAT connection on VM (KVM, qemu, libvirt, virt-manager, connman)

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1

I keep having to deal with this issue.
For whatever reason the NAT connection is lost.
This time even creating a my VM again from scratch is no longer working.
An e1000e connection does work.

virt-manager connection config in xml

<network connections="1">
  <name>default</name>
  <uuid>b728bff2-6215-4472-8d38-a5a797d328aa</uuid>
  <forward mode="nat">
    <nat>
      <port start="1024" end="65535"/>
    </nat>
  </forward>
  <bridge name="virbr0" stp="on" delay="0"/>
  <mac address="52:54:00:8c:9c:74"/>
  <ip address="192.168.122.1" netmask="255.255.255.0">
    <dhcp>
      <range start="192.168.122.2" end="192.168.122.254"/>
    </dhcp>
  </ip>
</network>

VM network interface config in xml

<interface type="network">
  <mac address="52:54:00:8d:cd:66"/>
  <source network="default" portid="94cebc1a-2b7b-41ba-91a4-22958fe3aef4" bridge="virbr0"/>
  <target dev="vnet4"/>
  <model type="virtio"/>
  <alias name="net0"/>
  <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
</interface>

ip addr on guest

image
image857×178 3.55 KB

ip addr on host

$ ip addr
...
4: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 52:54:00:8c:9c:74 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
9: vnet4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master virbr0 state UNKNOWN group default qlen 1000
    link/ether fe:54:00:8d:cd:66 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc54:ff:fe8d:cd66/64 scope link proto kernel_ll 
       valid_lft forever preferred_lft forever

network device

<interface type="network">
  <mac address="52:54:00:8d:cd:66"/>
  <source network="default" portid="94cebc1a-2b7b-41ba-91a4-22958fe3aef4" bridge="virbr0"/>
  <target dev="vnet4"/>
  <model type="virtio"/>
  <alias name="net0"/>
  <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
</interface>
2

Did you read the stable announcement?

3

What stable announcement?

4

Virtual machines using libvirt have no internet if the host uses UFW
This is a known bug 5. “Workaround” is to change the firewall with firewalld or to disable UFW.
Another easier workaround is to edit /etc/libvirt/network.conf, and add
firewall_backend = “iptables”

2 Likes
5

Does this count for Linux 6.6.41-1 as well?

$ inxi
CPU: quad core Intel Pentium Silver J5040 (-MCP-)
speed/min/max: 1174/800/3200 MHz Kernel: 6.6.41-1-MANJARO x86_64
Up: 1d 22h 59m Mem: 6.89/34.9 GiB (19.8%) Storage: 1.98 TiB (18.9% used)
Procs: 271 Shell: Bash inxi: 3.3.35

I forgot to tell by the way that e1000e connections work, but virtio doesn’t.
I had this issue before, but then rebuilding the VM worked back then.

6

Yes it works on 6.6. It can get reset on update unfortunately, seems like the packager forgot to include the file in the list of files to generate .pacnew. I dropped a line at F.Swan about it so hopefully it will be fixed.

About the choice of adapter - i can confirm something else is going on there, because my different virtual machines “like” one or the other. I still have not found the time to dig into it. I just switch as needed. I think it is dependent on the type of guest.

7

What do you mean by ‘“like” one or the other’?

8

One guest os worked only with e1000, one only with virtio. But i have deinstalled them since and cannot test now.

9

I’ve solved my own issue by editing my network interface xml model type to “virtio-net” instead of “virtio”.
I’m not sure why virt-manager only gives me two model options.

2 Likes
10

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