Problems with network bridge br0 after kernel change

    Hello community,


    since I had a problem with the last official kernel update in connection with ZFS, I recently swapped my OMV7 standard kernel for the Proxmox kernel 6.11.11-1-pve using the kernel plugin. This solved these problems (c.f. link).


    Unfortunately, I now have the problem that the network bridge br0 configured in the network interfaces in OMV no longer works. It is still there, but no more data is routed from enp5s0 to enp6s0.



    My internet router with DNS is connected to enp5s0. A Windows PC is connected to enp6s0, which is supposed to access the internet via the OMV PC. This can send data to the OMV NAS via this LAN connection, but it can no longer access the internet. It worked well before. Now, unfortunately, it no longer works. What could be the reason for this?


    Thank you very much for your support!


    Best regards

    Mic.

    do you try to delete & recreate your br0?, some times this works.

    Quote from Krisbee

    Mic2024 You could check:


    There has been no shift in the predictable NIC names, i.e. each MAC address still points the same NIC in the output of ip a

    I did not note down all information from ip a. I hope there was nothing changed.



    The PC on enp6s0 just tells that no DNS is available what is true if the bridge does not work anymore.

    Well I can see nothing has changed in the predictable NIC assignments, and your main bridge br0 is up. If you can ping an external ip or domain from OMV, your bridge is working. ( If you want to check the physical port that is enp6s0 you can of course swap the cable between your router and OMV to a port you want to test. )

    Thank you for your hint but this test would not help. The PC on enp6s0 does not get an IP address so I cannot ping it. The OMV PC still does not forward IP requests from the PC at enp6s0 to the router at enp5s0. This is the same behavior as I would not create an bridge br0. Anything else must sill be wrong.

    Quote from Mic2024

    I tried to make changes in the WebGUI and save it in OMV. A complete delete I did not try becuase this can resault that OMV in not reachable (e.g. by SSH) anymore.

    use a monitor & keyboard attached, I still think that is the sollution.

    Quote from Mic2024

    Thank you for your hint but this test would not help. The PC on enp6s0 does not get an IP address so I cannot ping it. The OMV PC still does not forward IP requests from the PC at enp6s0 to the router at enp5s0. This is the same behavior as I would not create an bridge br0. Anything else must sill be wrong.

    Your first post said the "bridge br0 no longer works" so I suggested that if OMV itself ( not your PC ) you ping an externaI IP or domain that in fact your bridge is still working at least on enp5s0 which connects your OMV server to your router. Did you test this?

    Quote from raulfg3

    use a monitor & keyboard attached, I still think that is the sollution.

    Hello everyone,


    I took the trouble today to delete the LAN bridge using the keyboard and screen and then set it up again. Unfortunately, that didn't help either. The PC that is connected to the OMV PC has no access to the rest of the network and doesn't get an IP address.


    I tried it with two different PCs (1x Windows, 1x Linux) and I also tried one of the other ports on the OMV PC. None of that had any effect. What else could be wrong?


    If that's helpful, here's the NetPlan that OMV created:

    Thank you for your support!


    Greetings

    Mic.

    I explained how with a couple of quick tests you'd satisfy yourself that your bridge was working, or not. But instead you deleted and re-configured it and are no further forward.


    Assuming all ports on your OMV br0 are working, the fact you were/are no longer getting an IP etc when connecting a PC to enp6s0 points to a problem with your router such a stale DHCP lease or a ip config problem on the PC. So check your router and the check your PC's network config.


    If you find nothing wrong on the router, then may be requesting a new DHCP lease on your PC will bring things to life. In Linux that's done with: dhclient <interface> (Sub PC interface name taken from ip a )

    Dear all,


    after one week of debugging and testing with a lot of sleepless nights, my network bridge is working properly again. I made so many tests and changes in the configuration I cannot clearly say, what really happened and what finally was the solution.


    In between I have seen that the bridge is not completely not working – only network traffic managed by IPv4 / DNSv4 was not working. Web pages using IPv6 were reachable but I do not know if this was the situation since the beginning of my problems. I was not aware that some web pages are reachable by IPv4 and some by IPv6. Here are two examples:



    I tried to document all my changes but cannot promise that it is complete. You should know I tried to fix the problem with the background that I have installed Pi-hole as Docker Container with a MacVLAN at 182.158.168.222 on my OMV-PC.


    I adapted the file /etc/resolv.conf to have the correct name servers available on the OMV-PC:


    Code
    domain home.router
search home.router
nameserver 182.158.168.222
nameserver fd00:0:0:0:4e6f:53ff:ef2e:222
nameserver 182.158.168.1
options edns0 trust-ad


    I added the correct DNS resolvers in the file /etc/systemd/resolved.conf. The IP 182.158.168.1 is my internet router which shall be the main target for DNSv4 and DNSv6 requests. This router will forward it to pi-hole (otherwise the DHCP does not work properly).


    Code
    [Resolve]
DNS=182.158.168.1 182.158.168.222 fd00:0:0:0:4e6f:53ff:ef2e:222


    To avoid that Linux will overwrite my changes I deactivated the automatic resolving by doing the following commands:


    Code
    sudo systemctl disable systemd-resolved.service
sudo systemctl stop systemd-resolved.service
sudo systemctl restart networking


    I have activated IP forwarding by using these commands:


    Code
    echo 1 > /proc/sys/net/ipv4/ip_forward
sudo sysctl -w net.ipv4.ip_forward=1
echo 1 > /proc/sys/net/ipv6/conf/all/forwarding
sudo sysctl -w net.ipv6.conf.all.forwarding=1


    To check, if these changes have been successful you can use these commands:


    Code
    sudo sysctl net.ipv4.conf.all.forwarding
sudo sysctl net.ipv6.conf.all.forwarding


    To make the changes permanent I added the following two lines to /etc/sysctl.conf:


    Code
    net.ipv4.ip_forward=1
net.ipv6.conf.all.forwarding=1


    To activate these changes, you need to enter:


    Code
    sudo sysctl -p


    I made some changes to the firewall rules. I make my live easier I created a bash script where I can change the rules easily for testing. Feel free to use it if you need i (name: firewall_rules.sh:


    Code
    +++ I try to upload the script in a 2nd posting. It is too large. +++

    In a final status I recommend you the rules for --save and --ipv6active.


    I increased the MTU value to 1500:


    Code
    sudo ip link set dev br0 mtu 1500


    I restared everything on the OMV-PC:


    Code
    sudo systemctl restart systemd-networkd
sudo systemctl restart networking


    And after this I also needed to reset the network configuration in my Windows PC connected to the network bridge on the OMV-PC:


    Code
    ipconfig /renew
ipconfig /release


    If you want to use network logging for security reasons as prepared in my above bash script you need to prepare it by doing these steps:


    Create an empty log file:


    Code
    tail -f /var/log/iptables.log


    Activate the additional firewall rules for logging my using my above script file:


    Code
    ./firewall_rules.sh --loggingactive


    Add the following two lines in the two files /etc/rsyslog.conf and /etc/rsyslog.d/iptables.conf. If a file does not exist, just create it.


    Code
    :msg, contains, "IPTables-" /var/log/iptables.log
& ~


    Restart the networking services:


    Code
    sudo systemctl restart rsyslog
sudo systemctl restart networking


    Check the log from time to time for issues:


    Code
    nano /var/log/iptables.log

    I also adapted the netplan file /etc/netplan/60-openmediavault-br0.yaml  created by OMV:



    These are a lot of things to be considered. Not it is working as expected. Maybe anyone else facing these issues this may help. But be careful with changes. The network settings can be very individual to your system.


    Regards

    Mic.

  • Mic2024

    Added the Label resolved

  • Mic2024

    Added the Label OMV 7.x

    btw: I had exactly the same issue today with the same kernel (Intel NICs). Even if I break the bonding didn't work till (coincidence?) a live cd. What I notice is that the interface names changed (not to predicted).

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