configuring a bridge network device configuration in RHEL9

[mschindl]

Hi,

I have a question of configuring a bridge network device configuration in RHEL9, which is not going online.

Interface br0 were created:

NAME                 UUID                                  TYPE      DEVICE 
enp2s0               79aca1f6-40da-4c79-8aa0-f0a6d39832fe  ethernet  enp2s0 
lo                   1dffc58c-8fe9-4a95-84fc-9c35e18b20c0  loopback  lo     
br0                  32838725-8e2e-4deb-ba22-f3d37e7a398f  bridge    --     
bridge-slave-enp2s0  45a4dc60-c2b0-42e7-80e2-1d2d80d3a6e4  ethernet  --

After deactivating the origin main interface enp2s0 and activating the bridge br0 with an IP address/manual, IGMP and STP disabled, it’s not going online/UP.

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: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether a8:a1:59:06:12:ab brd ff:ff:ff:ff:ff:ff
4: br0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:d0:45:d3:22:9f brd ff:ff:ff:ff:ff:ff
    inet 10.1.1.250/24 brd 10.1.1.255 scope global noprefixroute br0
       valid_lft forever preferred_lft forever

Any idea what could be wrong here?

[mschindl]

The NetworkManager brings up STP by default when you make a bridge, so there might be an issue caused by that? Maybe your switch has set the port to disabled or something along those lines?

> I used two different switches (Powerline and Netgear) and direct connection.

deleting the bridge. Bring down the physical interface to reset both the switch and Kernel connection state. Create the bridge in Cockpit while making sure span tree is disabled before enabling it?

> I did it several times with nmtui and nmcli, but also with cockpit.nmcli is faster to reproduce the issue.

I remember my issue had something to do with STP.
> Yes, I read this as well and disabled it.

::::::::::::::

[root@server ~]# nmcli con modify br0 bridge.stp no

::::::::::::::

I will try it at some point with RHEL8 again. As this is a physical system with only one link it takes time and phyiscial connection via keyboard & monitor.

Thank you for your tips.

[Duck]

I tried to reproduce your issue.

I used VMWare 17 and EL 9.3 fresh minimal install.

Using your commands:

nmcli con add type bridge autoconnect yes con-name br0 ifname br0
nmcli con add type bridge-slave autoconnect yes con-name ens160 ifname ens160 master br0
nmcli con modify br0 bridge.stp no
nmcli con down ens160
nmcli con up br0

ip addr showed me the exact same issue as you (no carrier on br0).

I deleted the br0 and essentially went back to start, then did:
nmcli con add ifname br0 type bridge con-name br0
nmcli con add type bridge-slave ifname ens160 master br0
nmcli con modify br0 bridge.stp no
nmcli con down ens160
nmcli con up br0

ip addr showed everything working with a valid DHCP lease on br0.

Wish it was that easy for me last time I did it =(
I was using bonds, VLANS and bridges. Maybe I just confused myself in the process.