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#1 2022-07-01 17:27:51

jenia
Member
Registered: 2014-07-12
Posts: 31

Setup bridge network systemd-networkd

I need to setup a bridge network on my machine but each time I try, the bridge does not get an IP and my ethernet card `eno1` does not have access to the internet.

Here is my setup for `systemd-networkd`:

[jenia@jenia network]$ pwd
/etc/systemd/network
[jenia@jenia network]$ files=(*)
[jenia@jenia network]$ for file in "${files[@]}";do echo "================="; echo $file; cat $file; echo ""; done
=================
bind.network
[Match]
Name=eno1

[Network]
Bridge=br0

=================
br0.netdev
[NetDev]
Name=br0
Kind=bridge

=================
br0.network
[Match]
Name=br0

[Network]
DHCP=ipv4
```

And here is my network configuration. Notice that `br0` does not have an IP for some reason.


[jenia@jenia network]$ ip addr
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: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master br0 state UP group default qlen 1000
    link/ether 78:24:af:36:1f:b5 brd ff:ff:ff:ff:ff:ff
    altname enp0s25
    inet6 fe80::7a24:afff:fe36:1fb5/64 scope link 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:0f:9b:b6 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
4: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether fe:8f:a3:0a:20:b2 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc8f:a3ff:fe0a:20b2/64 scope link 
       valid_lft forever preferred_lft forever
5: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br0 state UNKNOWN group default qlen 1000
    link/ether fe:54:00:cc:3c:51 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc54:ff:fecc:3c51/64 scope link 
       valid_lft forever preferred_lft forever

Can someone please give me a tip on how to setup my bridge network on my Archlinux install?

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#2 2022-07-01 18:47:20

stronnag
Member
Registered: 2011-01-25
Posts: 59

Re: Setup bridge network systemd-networkd

The following works for me:

$ cat ee-br0.netdev
[NetDev]
Name=br0
Kind=bridge

[Address]
ManageTemporaryAddress=true

$ cat ee-br0.network
[Match]
Name=br0

[Network]
DHCP=yes
MulticastDNS=yes
IPv6PrivacyExtensions=kernel

$ cat ee-eth0.network
[Match]
Name=eth*

[Network]
Bridge=br0
MulticastDNS=yes

[Link]
Multicast=true

MulticastDNS and IPv6 stuff optional

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#3 2022-07-03 22:24:14

jenia
Member
Registered: 2014-07-12
Posts: 31

Re: Setup bridge network systemd-networkd

Hey

Thanks for the tip but unfortunately it didn't work - there was no internet connection and the eno0 card had an IP somehow whereas I wanted the br0 to have an IP and to route traffic through it.

Here is what I tried the setup I tried (as you suggeested):

[jenia@jenia network]$ files=(*)
[jenia@jenia network]$ 
[jenia@jenia network]$ 
[jenia@jenia network]$ for file in "${files[@]}";do echo "================="; echo $file; cat $file; echo ""; done
=================
ee-br0.netdev
[NetDev]
Name=br0
Kind=bridge

[Address]
ManageTemporaryAddress=true

=================
ee-br0.network
[Match]
Name=br0

[Network]
DHCP=yes

MulticastDNS=yes
IPv6PrivacyExtensions=kernel

=================
ee-eno0.network
[Match]
Name=eth*

[Network]
Bridge=br0
MulticastDNS=yes

[Link]
Multicast=true


[jenia@jenia network]$ 
[jenia@jenia network]$ 
[jenia@jenia network]$ pwd
/etc/systemd/network

If you have any more tips, it'd be greatly appreciated as you can imagine wink

Happy fourth of July wink (if you're in that part of the woods wink)

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#4 2022-07-15 07:21:47

Grigorios
Member
Registered: 2021-01-10
Posts: 8

Re: Setup bridge network systemd-networkd

Hey, it could be a problem with your DHCP Server, maybe it is supplying addresses only to known mac addresses?
A second thing that comes to my mind is, if you first created the network device and restarted systemd-networkd to see if it got created and then added the network configuration without deleting the created br0 interface, systemd-networkd won't recreate the interface but use the existing without overwriting it's configuration. If that is the case, delete the br0 interface with $ip link delete br0 and then restart systemd-networkd.

Greetings

Grigorios

Last edited by Grigorios (2022-07-15 07:22:06)

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#5 2022-07-26 01:00:43

jenia
Member
Registered: 2014-07-12
Posts: 31

Re: Setup bridge network systemd-networkd

Hey Grigorios. Thanks for all you kind help.

I noticed that there was a typo in my ee-eno0.network file. "Name" should have been en* not eth*  I corrected it and deleted the br0 bridge as you suggested. Here is the result:

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: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master br0 state UP group default qlen 1000
    link/ether 78:24:af:36:1f:b5 brd ff:ff:ff:ff:ff:ff
    altname enp0s25
    inet 192.168.1.123/24 brd 192.168.1.255 scope global dynamic noprefixroute eno1
       valid_lft 86348sec preferred_lft 75548sec
    inet6 fe80::7a24:afff:fe36:1fb5/64 scope link 
       valid_lft forever preferred_lft forever
4: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:0f:9b:b6 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
5: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether fe:8f:a3:0a:20:b2 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::fc8f:a3ff:fe0a:20b2/64 scope link 
       valid_lft forever preferred_lft forever

As you can see, the eno1 gets an IP but the internet is still not working for some reason. Also the bridge has no IP.

Any further pointers?

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#6 2022-07-26 01:09:52

jenia
Member
Registered: 2014-07-12
Posts: 31

Re: Setup bridge network systemd-networkd

Here by the way are the contents of my networkd config files:

[jenia@jenia network]$ cat ee-br0.netdev 
[NetDev]
Name=br0
Kind=bridge


[Address]
ManageTemporaryAddress=true
[jenia@jenia network]$ 
[jenia@jenia network]$ 
[jenia@jenia network]$ 
[jenia@jenia network]$ cat ^C
[jenia@jenia network]$ cat ee-br0.network
[Match]
Name=br0

[Network]
DHCP=yes
[jenia@jenia network]$ 
[jenia@jenia network]$ 
[jenia@jenia network]$ 
[jenia@jenia network]$ cat ee-eno0.network
[Match]
Name=en*

[Network]
Bridge=br0
MulticastDNS=yes

[Link]
Multicast=true

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#7 2022-07-31 08:21:16

Grigorios
Member
Registered: 2021-01-10
Posts: 8

Re: Setup bridge network systemd-networkd

Hello,

based on your ee-br0.network file, I can see that you have not configured an IP-address for your br0 device.
The idea is, that your internet facing device eno1 has no IP-address configured and works as a slave for the br0 device which has got an IP-address configured (via DHCP, or static).
So you should leave your eno1 interface not configured and only bind it to the br0 interface, which you already did in ee-eno0.network.
So what you should do is create a br0.network file and configure it with an IP-address and make sure that you do not have a .network file  that assigns eno1 with an IP-address.

Greetings

Grigorios

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