Unable to make bridge interface UP state

Raheel

6/1/24, 9:43 AM

I am just learning networking, Pardon if my question does not give all details, I can provide if needed.

I am trying to learn network namespaces in Linux.

I have created two namespaces red and blue

ip netns

blue (id: 1)
red (id: 0)

I have also created a bridge interface and attached veth one end on namespace and one end on brdige interface as follows

ip link add v-net-0 type bridge
ip link set dev v-net-0 up

ip link add veth-red type veth peer name veth-red-br
ip link add veth-blue type veth peer name veth-blue-br

ip link set veth-red netns red
ip link set veth-red-br master v-net-0

ip link set veth-blue netns blue
ip link set veth-blue-br master v-net-0

The problem is that the bridge interface is not showing UP state

ip link show

18: v-net-0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
    link/ether 7a:99:f7:ca:7e:f1 brd ff:ff:ff:ff:ff:ff
19: veth-red-br@if20: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master v-net-0 state DOWN mode DEFAULT group default qlen 1000
    link/ether e2:ce:34:7b:23:31 brd ff:ff:ff:ff:ff:ff link-netns red
21: veth-blue-br@if22: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master v-net-0 state DOWN mode DEFAULT group default qlen 1000
    link/ether 5a:dc:4f:87:63:1a brd ff:ff:ff:ff:ff:ff link-netns blue

Link up both veth on namespaces

ip -n red link set veth-red up
ip -n blue link set veth-blue up

Also the bridge utils showing disabled state, whereas the document I am following says it should be in forwarding state

bridge link

19: veth-red-br@if20: <BROADCAST,MULTICAST> mtu 1500 master v-net-0 state disabled priority 32 cost 2
21: veth-blue-br@if22: <BROADCAST,MULTICAST> mtu 1500 master v-net-0 state disabled priority 32 cost 2

Help appreciated. Thanks

129

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networking

linux-networking

network-namespace

larsks

6/1/24, 1:30 PM

You are never calling `ip link set <device> up` for your veth links.

Raheel

6/1/24, 2:42 PM

it get missed from the question, But I am calling it

Raheel

6/1/24, 2:43 PM

updated my question

larsks

6/1/24, 3:05 PM

You're still not setting `veth-red-br` and `veth-blue-br` `up`.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Unable to make bridge interface UP state

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