Questions tagged [bridge]

A network bridge is a network device which transparently forwards packets between two or more network segments so that they appear as one local area network (LAN).

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Old server with 2 IPs with libvirt and KVM and bridge Centos 6

After hardware failure, bridge not working 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 ...
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Lower throughput in a Bridge created as a Ethernet Switch in a Ubuntu Server

The setup is given below. I have a server with NIC(eth0 and eth1). I have created a bridge br0. The idea is I want to send the packets received from eth0 via br0 to eth1. (Laptop)___________ Ubuntu ...
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Can't add wlan0 to bridge br0: Operation not supported

Objective: I am trying to use my raspberry pi as an access point. More precisely, what I am trying to achieve is to use wlan1 as the access point and either usb0 or wlan0 as the "sources" of ...
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Unable to get a namespace to access the external network

I am running Linux in a VirtualBox environment. I have successfully defined 2 namespaces connected via a bridge that can talk to each other. I want to be able to get UDP packets out onto the actual ...
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1 answer
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Virtual router in homelab Proxmox VM: how to send requests from main/home network to VM behind virtual router?

I have a homelab setup like this (diagram is also available here): One thing to note here is, my Proxmox host just has 1 NIC for ethernet cable. It has WiFi too but I decided not to use it because it ...
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To finder "who" created the bridge

Some bridge is blocking some IP range. #ifconfig br-0674396486d8: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet 172.19.0.1 netmask 255.255.0.0 broadcast 172.19.255.255 I would like to ...
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bridging traffic between 2 network cards using CentOS

i have the following scenario a machine with 3 NICs machine X - NIC A. IP 192.168.188.x -> Internet | - NIC B. IP 192.168.8.1 -> static connected to VOIP Device ...
2 votes
1 answer
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How to allow VLAN untagged packet to pass through when using VLAN aware bridge

I'm using VLAN aware bridge. I have an interface that I need that only packets with VID 10 and 20 could pass through, any other VIDs should be dropped. I configured the interface like that: bridge ...
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Docker do not link virtual interfaces to virtual network(bridge)

When create and start my all instances everything looks fine but even though do routing properly, my instances still cannot communicate each others. I have use this this command for each instance. ip ...
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Does the linux bridge only learn MAC address through ARP broadcast?

For a particular use case, I created a network of docker containers in which any type of ARP packet is disabled. In an experiment with many machines, I cannot allow the use of broadcast. Each ...
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Bridge won't get DHCP address if network available AFTER boot

I have 2 ethernet ports bridged as follows (/etc/network/interfaces.d/br0): auto br0 iface br0 inet dhcp bridge_ports enp1s0 enp2s0 bridge_fd 0 bridge_waitport 0 ...
3 votes
1 answer
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netplan - how to set up a bridge with LAN and AP?

I'm trying to set up a bridge device consisting of a LAN interface and WLAN interface in AP mode. Internet is provided by the LAN interface; other devices will connect to WLAN interface to connect to ...
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How do I provide Ethernet to a couple of servers that connects to WiFi using e.g. a Raspberry Pi?

I have good WiFi and a couple of servers that have Ethernet interfaces. I would like to use e.g. a Raspberry Pi to connect to my existing good WiFi and then provide Ethernet network access with a ...
3 votes
1 answer
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What is the net.bridge.bridge-nf-call-iptables kernel parameter?

I am following this guide of installing kubernetes with kubeadm, and as part of the installation process, I need to set the following kernel parameters in sysctl.d/99-kuvernetes-cni.conf: net.bridge....
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How to route the user-defined docker bridge network out of VPN tunnel?

I am trying to setup a Squid proxy in order to route some sites in my browser (using .pac file) out of VPN (they are unreachable inside the tunnel). For this reason I use Squid proxy docker container ...
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Why does a bridge interface need an IP?

I create a network bridge interface, then start several QEMU instances which add tap devices to that bridge. I found that these instances cannot ping each other until I assign an IP address to the ...
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How to tell qemu to randomly assign MAC addresses

I'm starting three Qemu VMs, each with several network interfaces. The network interface config looks like this: -nic user,hostfwd=tcp::"${ssh_ports[$machine]}"-:22,model=virtio-net-pci \ -...
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How can I make Linux generate different MAC addresses for different bridge devices which are on different PCs?

I have just upgraded two servers from Debian 10 (Buster) to Debian 11 (Bullseye). Afterwards, I could not reach either of them via the network any more. After some investigation, the following problem ...
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KVM setup on dedicated server - need additional IP?

(This is a beginner's question) I would like to have two (or more) virtual machines (KVM qemu based) on a dedicated server (Hetzner). How many IPv4 address do I need? I have one main IPv4 address. ...
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Network routing through veth0 / bridge for userspace QEMU VM?

I would like to filter and capture traffic from a virtual machine. This VM must run in userspace. Capturing requires root, I know (though I hope to minimise root activity needed later). The easiest ...
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network bridge and router mac whitelisting

For a [corporate] router that is locked down... has MAC filtering and whitelisting and all that, such that plugging in any new server on an open port will not receive a DHCP ipv4 address (but it will ...
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nmcli bridge refuses to come up

I tried running the commands found here But my bridge refuses to come up. Stuck in DOWN. the slave-bridge interface is ethernet. No wifi on this host. Tried using ip link to bring the interface up ip ...
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Ubuntu 22.04 netns with veth connected to bridge unable to ping gateway

Hey guys this is probably just something stupid I'm missing, but I'm having trouble setting up a net namespace to use for my VPN. The weird part is that this script/setup was working, and has suddenly ...
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Why is bridge-utils slowing down ifupdown-pre.service at boot?

Since I configured a bridged interface, I noticed that the boot went from 3-4 seconds to about 20 seconds. Here are my investigations, the ifupdown-pre.service is to blame. But why ? Note1 : I'm on ...
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1 answer
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Adding a physical ethernet interface to kvm qemu bridge

I'm following this excellent article to use bridged networking with libvirt and KVM, however there are some fundamental knowledge I'm lacking for me to fully understand/follow it. The article says, ...
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1 answer
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Setting IP forwarding with a bridge

I'm familiar with how to set IP forwarding between two interfaces, and it always worked. Now I have a different scenario where I want to set IP forwarding from a local network bridge to an output ...
1 vote
1 answer
129 views

How to make a virtual NIC that has its own MAC and IP address?

On Ubuntu, I need to make it seem like there are multiple, independent machines on a real network. This needs to be done without creating any additional VMs. At first, I thought of IP address aliasing,...
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How do I bridge an ethernet device to the wireless network interface from within a VirtualBox Ubuntu 20.04 LTS VM?

I have a VirtualBox Ubuntu VM, the "VM", set up on my primary Windows machine, using bridged VirtualBox connections to the wireless interface and the ethernet port (i.e. Ethernet <-> ...
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ZeroTier L2/bridge in LXC container under PVE: ZeroTier interface not added to the bridge

I would like to setup a L2/bridge between my LAN and few ZeroTier remote clients, as described in the official documentation, with a Raspberry Pi and with an OpenWRT router On some site I currently ...
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Bridging Ethernet Interface on OpenBSD and Other Problems

I am currently setting up an OpenBSD firewall, router, and dns server. I've been following various guides online with the bulk of my configuration coming from the OpenBSD site and the pf configuration ...
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IPtables DNAT with linux bridges (no interface addresses)

I've been doing some experimenting with iptables and bridges, and this scenario is just in a lab, but I've encountered some interesting functionality and would like some explanation as to what is ...
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Bridge interface connects to host instead of libvert guest

I have a Ubuntu host and I'm running a VM. I want the host to have the static IP 192.168.170.2 and I want the guest to have 192.168.170.3. I have my netplan file setup like so network: ethernets: ...
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ipv4 forwarding breaks bridges and veths

I've successfully gotten the following to work: ip netns add quarantine ip link add eth0-q type veth peer name veth-q ip link add br0 type bridge ip link set veth-q master br0 ip link set br0 up ip ...
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Bridge two physical interfaces without losing IP connectivity

I would like to bridge two physical interfaces (eth0 and eth1) programmatically, without them losing IP connectivity. As soon as I set eth0's master using sudo ip link set eth0 master br0, pings will ...
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0 answers
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network bridge not detecting particular device, how to troubleshoot?

I'm on 18.04 ubuntu, I have a bridge br0 setup(static 169.254.0.10) that is working with some network devices(169.254.0.40, 169.254.0.50). I have a 3rd device(169.254.0.60) that I want to connect to ...
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Create bridged connection for VMs without losing host IP/Connectivity [duplicate]

I'm migrating my VM host from VMware to KVM. In VMware, a network bridge is available out of the box. In Linux, it is not. I created a bridge, but when I bound my physical interface to it I lost ...
4 votes
1 answer
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Linux bridge: what does master mean in the "ip link set"?

In the following diagram, each color stands for a network namespace, which is connected by a Linux bridge v-net-0. veth-red and veth-red-br are a pair of veth. veth-blue and veth-blue-br are a pair ...
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Who loads bridge.ko modules when Linux system starts?

When my CentOS Linux system starts, bridge.ko and ebtable_broute are loaded, I'd like to know which module is loading these modules. [root]# lsmod | grep bridge bridge 266240 0 stp ...
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Linux bridge, trunk and PVID

Following up my other question I'd like to clarify the following: To configure the bridge interface rather than one of its port, the additional keyword self is needed. The routing stack (at layer 3) ...
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1 answer
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Linux bridge with trunk ports and self bridge port

I created VLAN-aware bridge with command and add relevant interfaces: % ip link add br0 type bridge vlan_filtering 1 % ip link set dev eth0 master br0 ... (and repeat this for eth1, eth2, eth3) Now, ...
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how to set default gateway after ifconfig. part 2

I have an android emulator on bridge and the network is set up via "ifconfig eth1 192.168.41.100" The bridge is 192.168.41/24 and gateway is 192.168.41.1. It works well (it is essentially a ...
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Raspberry Pi bridge eth0\eth1

I have a Raspberry Pi and a device/sensor which connects to the Pi via eth1. Eth0 is connected to my router, giving access to the internet. I'd like to bridge my eth0/eth1, so that traffic from the ...
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1 answer
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Packet Forwarding on Debian 11

I am running Debian 11 on a small form factor box. I am wanting to take all traffic from a network tap upstream on ethernet interface eno2 and output it on sfp+ interface eno8. I've set up bridging ...
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1 answer
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Linux L2 bridge blocks ip packets which are addressed to a listening port on the host

On my Server I have a bunch of vms, connected by a simple L2 linux bridge to an OPNsense VM for firewalling and routing between the vms. The OPNsense vm is connected via macvtap to the single enp3s0 ...
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Why can an interface not simply be added to a bridge?

My mental model of Linux' bridge is wrong. I have always considered a bridge similar to a simple, unmanaged switch: You plug in some ethernet cables, and data is then copied from one port to another ...
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1 vote
1 answer
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Run > 1024 docker containers

Normal Docker is limited to 1023 containers due to the bridge being limited to 1023 MAC addresses. But what if you have several bridges? Can you then have more than 1023 containers? And can you ...
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Redirect specific traffic between two port on same device

I have two running SIP applications on a Debian buster server, one app use port 1000 (a softphone) and another one using port 2000 (VoIP server like FreePBX). both of them are on the same machine and ...
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2 answers
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Bridge gets random MAC instead of port address

I have a fresh install of Debian 11 and did a bridge setup: auto br0 iface br0 inet dhcp bridge_ports eno1 What I expect is that br0 has the same MAC address as eno1 but it gets a randomly ...
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Proper Isolation of Bridge Networks

Proper Isolation of Bridge Networks I am trying to set up a private network space, isolated from a public network space. In the public space, I want my guest OS NIC to get it's IP address via DHCP ...
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Adding a VLAN-transparent bridge to Linux (Debian)

On my current Debian system I use VLAN tagging and I create bridges br-wan and br-lan that I use for LXC containers: auto lo br-lan br-wan iface lo inet loopback iface br-wan inet manual     ...
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