sampsonf
(Sampson Fung)
June 20, 2021, 10:27pm
1
I have a Bridge interface br0 defined via
/etc/NetworkManager/system-connections
[connection]
id=br0c
uuid=17aa4482-0bc6-4047-9648-2e7fcc5ac767
type=bridge
interface-name=br0
permissions=
[bridge]
stp=false
[ipv4]
dns-search=
method=disabled
[ipv6]
addr-gen-mode=stable-privacy
dns-search=
method=disabled
[proxy]
How can I assign a mac address to this interface?
I am multi-booting different Fedora editions in this systems, so I want to have the same MAC address for:
Fedora 34
Fedora Silverblue 34
etc
In addition, OpenWrt router allow me to define a static IPv6 assignment based on DUID:
Hostname MAC-Address IPv4-Address Lease time DUID IPv6-Suffix (hex)
amdf xx:xx:xx:xx:xx:xx 192.168.1.34 2h 0004bc612e0cc9940f4a8978801549f5619e 34
How can I override the DUID as well?
1 Like
Is your bridge displayed with ip link sh
? If so does it show a MAC address?
I notice that I have a virbr0
bridge that shows no MAC in NetworkManager, but does show one from the ip
utility. So there has to be some mechanism assigning it a MAC. (Below output was edited to only show relevant information).
nmcli con show
NAME UUID TYPE DEVICE
virbr0 4623ff0b-8fc5-410a-87a5-eea23d4782a1 bridge virbr0
nmcli con show virbr0 | grep -i mac
bridge.mac-address: --
ip link sh virbr0
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
link/ether 52:54:00:93:11:9b brd ff:ff:ff:ff:ff:ff
sampsonf
(Sampson Fung)
June 21, 2021, 1:54am
3
virbr0 is created by libvirt, so I will not touch it normally.
For the br0, it is created using nm-connection-editor . From the edotir UI, there is no way to override the MAC address of the bridge interface.
Finally, I solved the MAC address override by editing the [bridge] section:
[bridge]
stp=false
mac-address=xx:xx:xx:xx:xx:xx
So now, my next task is to override the ipv6-duid for my VLAN connections.
I know vibro0
is made by libvirt. I was curious as to when you made your bridge and didn’t specify a MAC, if one was created for it. And if it was if it displayed as my virbr0
did: not in NetworkManager but does with ip
.
sampsonf
(Sampson Fung)
June 21, 2021, 1:58am
5
Let me remove the override, reboot and see.
== update ==
As checked:
When the override is defined, nmcli con show <connection>
shows the MAC address I added to the connection.
When the override is removed, nmcli con show indeed show the as undefined bridge.mac-address: --
So it is auto-generating the MAC when the interface is up . As
nmcli
is showing:
br0: connected to br0c
"br0"
bridge, xx:xx:xx:xx:xx:xx, sw, mtu 1500
Was there also no MAC address for ip link sh
?
sampsonf
(Sampson Fung)
June 21, 2021, 4:39am
7
ip link show
always list the MAC address correctly.
vgaetera
(Vladislav Grigoryev)
June 21, 2021, 5:42am
8
nmcli connection modify id br0c \
ethernet.cloned-mac-address MACADDR \
ipv6.dhcp-duid DUID
nmcli connection up id br0c
nm-settings-nmcli: NetworkManager Reference Manual
1 Like
sampsonf
(Sampson Fung)
June 21, 2021, 6:51am
9
MACADDR works, but DUID do not.
nmcli con show br0c | grep duid
ipv6.dhcp-duid: 0004BC612E0CC9940F4A8978801549F5619E
Active DHCPv6 leases at Router
Active DHCPv6 Leases
Host IPv6 address DUID Lease time remaining
amdf xx::857 yy::857 00047e313c4ee85714f5f79657e0e7ce955b 0h 0m 24s
Static Leases at Router
|Hostname|MAC-Address|IPv4-Address|Lease time|DUID|IPv6-Suffix (hex)||
|amdf|D6:06:7E:0A:67:B4|192.168.102.11|7m|0004BC612E0CC9940F4A8978801549F5619E|11|
vgaetera
(Vladislav Grigoryev)
June 21, 2021, 7:25am
10
This just works for me:
# OpenWrt
uci add dhcp host
uci set dhcp.@host[-1].duid="000100004fd454041c6f65d26f43"
uci set dhcp.@host[-1].hostid="23"
uci commit dhcp
/etc/init.d/odhcpd restart
# Fedora
nmcli connection modify id vghome ipv6.dhcp-duid 000100004fd454041c6f65d26f43
nmcli connection up id vghome
nmcli -g IP6.ADDRESS connection show id vghome
sampsonf
(Sampson Fung)
June 21, 2021, 7:33am
11
OK - finally I find out why.
nmcli con
NAME UUID TYPE DEVICE
vl102c c3b65409-5617-4ef8-9afd-5136ab97afe1 vlan 102
vl224c 7335c403-a1f3-446a-af21-5a043ea1a26e vlan 224
br0c 17aa4482-0bc6-4047-9648-2e7fcc5ac767 bridge br0
enp1s0c 7ca5dd24-9e35-4809-8deb-43cc4dc389e0 ethernet enp1s0
My br0c have both IPv4 & 6 disabled.
My IPv6 is running at vl224c, so the duid assignment need to be done to vl224c, instead of br0c.
But MACADDR override can be done to br0c .
1 Like
system
(system)
Closed
July 19, 2021, 7:33am
12
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