Network Bridge for a Virt Manager KVM guest, not giving ping for host

Misekayek0l · January 8, 2024, 12:19pm

I have a Virt Manager Guest with the following configuration:

<interface type="bridge">
  <mac address="11:11:11:11:11:11"/>
  <source bridge="nm-bridge0"/>
  <target dev="vnet1"/>
  <model type="virtio"/>
  <alias name="net0"/>
  <address type="pci" domain="0x0000" bus="0x07" slot="0x00" function="0x0"/>
</interface>

Running ip a in the guest prints:

$ ip a
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
    inet6 ::1/128 scope host noprefixroute 
       valid_lft forever preferred_lft forever
2: enp7s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 52:54:00:87:60:51 brd ff:ff:ff:ff:ff:ff
    inet 169.254.32.164/16 brd 169.254.255.255 scope global noprefixroute enp7s0
       valid_lft forever preferred_lft forever
    inet6 fe80::5054:ff:fe87:6051/64 scope link 
       valid_lft forever preferred_lft forever

but trying to ping the guest from the host gives this:

$ ping 169.254.32.164
PING 169.254.32.164 (169.254.32.164) 56(84) bytes of data.
^C
--- 169.254.32.164 ping statistics ---
9 packets transmitted, 0 received, 100% packet loss, time 8180ms

How do I have to correct this?

Misekayek0l · January 8, 2024, 12:32pm

Actually runing ping 1.1.1.1 in the guest give the following:

$ LANG=C ping 1.1.1.1
PING 1.1.1.1 (1.1.1.1) 56(84) bytes of data.
From 169.254.32.164 icmp_seq=1 Destination Host Unreachable
From 169.254.32.164 icmp_seq=2 Destination Host Unreachable
From 169.254.32.164 icmp_seq=3 Destination Host Unreachable
^C
--- 1.1.1.1 ping statistics ---
5 packets transmitted, 0 received, +3 errors, 100% packet loss, time 4083ms
pipe 3

Sauerland · January 8, 2024, 12:42pm

Post from the host:
ip a

Misekayek0l · January 8, 2024, 12:47pm

# ip a
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
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether d8:c4:97:f2:58:48 brd ff:ff:ff:ff:ff:ff
    altname enp2s0f1
    inet 192.168.0.2/24 brd 192.168.0.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 2002:c0a8:140:1:ad74:61b9:77e1:dff2/64 scope global temporary dynamic 
       valid_lft 300sec preferred_lft 300sec
    inet6 2002:c0a8:140:1:fb2e:ecfc:1c6e:1b5b/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 300sec preferred_lft 300sec
    inet6 fe80::f3b5:bd70:ae9:77f4/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 72:14:6c:55:f9:40 brd ff:ff:ff:ff:ff:ff permaddr f8:a2:d6:ae:1c:79
    altname wlp3s0
13: nm-bridge0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether fe:54:00:87:60:51 brd ff:ff:ff:ff:ff:ff
15: vnet2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master nm-bridge0 state UNKNOWN group default qlen 1000
    link/ether fe:54:00:87:60:51 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc54:ff:fe87:6051/64 scope link 
       valid_lft forever preferred_lft forever

Misekayek0l · January 8, 2024, 1:28pm

Do you need something else?

Sauerland · January 8, 2024, 2:14pm

I do not use Networkmanager for such things, I use wicked.

I do not see on which hardware (on the host) your bridge is build?

My bridge is setup on eth0:

ip a
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
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master br0 state UP group default qlen 1000
    link/ether 10:7b:44:4a:5a:16 brd ff:ff:ff:ff:ff:ff
    altname enp5s0
3: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 70:8b:cd:2e:5b:2b brd ff:ff:ff:ff:ff:ff
    altname wlp4s0
4: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 00:e0:4c:68:13:c2 brd ff:ff:ff:ff:ff:ff
    altname enp0s20f0u2u4
5: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 10:7b:44:4a:5a:16 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.2/24 brd 192.168.0.255 scope global br0
       valid_lft forever preferred_lft forever
.
.
.
.
.

And my qemu/Virtualbox clients are getting an IP from 192.168.0.x Network

Misekayek0l · January 8, 2024, 2:23pm

What about giving my Bridge config file:

# cat /etc/NetworkManager/system-connections/Ethernet\ connection\ 1.nmconnection
[connection]
id=Ethernet connection 1
uuid=ba7ca56a-9d91-4885-a6be-211cdc7311b7
type=ethernet
interface-name=eth0
master=a6a1d55f-a0ef-4a54-9927-47ca7fab4133
slave-type=bridge

[ethernet]
auto-negotiate=true
mac-adress=52:54:00:87:60:52
wake-on-lan=0

[bridge-port]

malcolmlewis · January 8, 2024, 2:37pm

@Misekayek0l two profiles are needed with NM for example;

cat /etc/NetworkManager/system-connections/Bridge\ connection\ enp8s0.nmconnection

[connection]
id=Bridge connection enp8s0
uuid=
type=bridge
interface-name=br0
timestamp=1688338438

[ethernet]

[bridge]

[ipv4]
method=disabled

[ipv6]
addr-gen-mode=stable-privacy
method=disabled

[proxy]

cat /etc/NetworkManager/system-connections/br0\ port\ 1.nmconnection 

[connection]
id=br0 port 1
uuid=
type=ethernet
interface-name=enp8s0
master=br0
slave-type=bridge
timestamp=1688338438

[ethernet]
mac-address=

[bridge-port]

Misekayek0l · January 8, 2024, 2:55pm

After copying your example configuration and restart this is my ip a:

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
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether d8:c4:97:f2:58:48 brd ff:ff:ff:ff:ff:ff
    altname enp2s0f1
    inet 192.168.0.2/24 brd 192.168.0.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 2002:c0a8:140:1:ec85:73c:16df:baa0/64 scope global temporary dynamic 
       valid_lft 297sec preferred_lft 297sec
    inet6 2002:c0a8:140:1:fb2e:ecfc:1c6e:1b5b/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 297sec preferred_lft 297sec
    inet6 fe80::f3b5:bd70:ae9:77f4/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 4a:dc:95:e0:38:93 brd ff:ff:ff:ff:ff:ff permaddr f8:a2:d6:ae:1c:79
    altname wlp3s0
4: virbr0: <BROADCAST,MULTICAST> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:b4:e7:34 brd ff:ff:ff:ff:ff:ff

Misekayek0l · January 8, 2024, 2:56pm

Note that eth0 is my ethernet connection to online communications

malcolmlewis · January 8, 2024, 4:17pm

@Misekayek0l you need a dedicated ethernet interface for the bridge.

Misekayek0l · January 8, 2024, 4:18pm

I have any aditional network port in the laptop.

Misekayek0l · January 8, 2024, 4:18pm

Also it it a network interface for every VM?

malcolmlewis · January 8, 2024, 4:24pm

@Misekayek0l so you only have one ethernet and you can’t use it for the bridge? No a bridge interface can be used on all virtual machines. Is this a laptop, if so look at getting a USB to Ethernet device to use…

Misekayek0l · January 8, 2024, 4:32pm

So you are saying that I only have to buy a usb to ethernet and a cable to connect all of my virtual machines?

malcolmlewis · January 8, 2024, 4:36pm

@Misekayek0l yes, I have a couple here I use to use (I run two bridges), I have a dedicated 4 port card now in this desktop, two bridges and two interfaces for virtual machines.

Sauerland · January 8, 2024, 7:23pm

One Ethernet card using as bridge and using the bridge for the Internet…

Misekayek0l · January 15, 2024, 9:11pm

Just setup the second network card in the host with the example configuration and still not working:

# ip a
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
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether d8:c4:97:f2:58:48 brd ff:ff:ff:ff:ff:ff
    altname enp2s0f1
    inet 192.168.0.2/24 brd 192.168.0.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 2002:c0a8:140:1:5b5c:28e4:6740:edd6/64 scope global temporary dynamic 
       valid_lft 300sec preferred_lft 300sec
    inet6 2002:c0a8:140:1:fb2e:ecfc:1c6e:1b5b/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 300sec preferred_lft 300sec
    inet6 fe80::f3b5:bd70:ae9:77f4/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:00:00:00:2b:49 brd ff:ff:ff:ff:ff:ff
    altname enp0s16u3
    inet 192.168.0.135/24 brd 192.168.0.255 scope global dynamic noprefixroute eth1
       valid_lft 7121sec preferred_lft 7121sec
    inet6 2002:c0a8:140:1:7bf0:3270:b70d:cbff/64 scope global temporary dynamic 
       valid_lft 300sec preferred_lft 300sec
    inet6 2002:c0a8:140:1:476f:4f09:bf49:ae10/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 300sec preferred_lft 300sec
    inet6 fe80::d57b:f76b:9f53:303f/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
4: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 7e:9d:50:dc:49:45 brd ff:ff:ff:ff:ff:ff permaddr f8:a2:d6:ae:1c:79
    altname wlp3s0
5: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:b4:e7:34 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.1/24 brd 192.168.100.255 scope global virbr0
       valid_lft forever preferred_lft forever

Actually Virtual Manager cannot start the machine and gives me this error:

 Cannot get interface MTU on 'br0': No such device

Here my NIC configuration in Virtual Manager:

<interface type="bridge">
  <mac address="52:54:00:87:60:51"/>
  <source bridge="br0"/>
  <model type="virtio"/>
  <address type="pci" domain="0x0000" bus="0x07" slot="0x00" function="0x0"/>
</interface>

malcolmlewis · January 15, 2024, 9:24pm

@Misekayek0l Have a read of this thread to see how to create (your second interface has an ip address…) with nmcli or just a text file: https://forums.opensuse.org/t/how-do-i-install-and-have-wicked-appear-as-an-option-in-yast2-system-network-settings/169455

Misekayek0l · January 15, 2024, 9:30pm

Using this exact configuration just with eth1 instead of enp8s0

It is not working