Because a bridge is an ethernet device it needs a MAC address. A linux bridge can originate things like spanning-tree protocol frames, and traffic like that needs an origin MAC address.
A bridge does not require an ip address. There are many situations in which you won't have one. However, in many cases you may have one, such as:
When the bridge is ...
A bridge does not need an IP address to function. Without one it will just perform layer 2 switching, spanning tree protocol and filtering (if configured).
An IP address is required if you want your bridge to take part in layer 3 routing of IP packets.
As an example you can setup a bridge without an IP address in Debian/Ubuntu using the following in /etc/...
The NIC represents the uplink cable. A cable is layer 1, not layer 3.
Now the Bridge works as the device that is being addressed for network traffic (incoming) on the server - either on layer 2 (Ethernet/MAC) and/or layer 3 (IP).
So the device that responds to ARP-requests is the bridge - which is good, since it needs to distribute the traffic to the other ...
The interface virbr0-nic is not a bridge, but a normal ethernet interface (although a virtual one, created with ip add type veth).
It's there so that the bridge has at least one interface beneath it to steal it's mac address from. It passes no real traffic, since it's not really connected to any physical device.
The bridge would work without it, but then ...
You can use the more-or-less undocumented -d option to ip(8), which tells you the type of certain devices including tun, tap & veth:
$ ip -d a
6: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
link/ether 52:54:00:c8:12:ec brd ff:ff:ff:ff:ff:ff promiscuity 0
...note tun ...
For configuring a bridge from ethernet to wifi, it is as simple as doing in your /etc/network/interfaces:
iface eth0 inet manual
iface wlan0 inet manual
iface br0 inet static
bridge_ports eth0 wlan0
Replace the IP address with ...
The comment from Stéphane Chazelas provides the hint to the answer.
According to Bridge-nf Frequently Asked Questions bridge-nf enables iptables, ip6tables or arptables to see bridged traffic.
As of kernel version 2.6.1, there are five sysctl entries for bridge-nf behavioral control:
bridge-nf-call-arptables - pass bridged ARP traffic to arptables' ...
I suspect your problem is more because whatever sends the UDP packets is not adding a newline character the commands (as in they should send "play\n" and not just "play").
In any case, if you want a new TCP connection to be created for each of the UDP packets, you should use udp-recvfrom instead of udp-listen in socat:
socat -u udp-recvfrom:3333,fork tcp:...
Here's the output from one of my bridging Linux machines:
With brctl showstp, you can print the list of interfaces and their spanning-tree parameters involved with the bridging. There, in parenthesis, you'll find the interface index of the constituent interfaces - that's what is referenced in brctl showmacs.
# brctl show
bridge name bridge id ...
Yes: you can set the bridge to be VLAN aware.
The bridge will then handle VLAN IDs attached to frames crossing it, including tagging and untagging them according to configuration, and will send a frame belonging to a given VLAN only to ports configured to accept it. This moves all the settings to the bridge itself rather than having to use VLAN sub ...
On a Centos 7 it looks like this.
Check if AP is possible at all:
iw list | less
and search for "AP" among supported interface modes.
Browse your devices to find the name:
And setup and start your hotspot.
Mind that wifi-device, connection-name and hotspot-ssid are specific to your system.
nmcli c add type wifi ifname wifi-device con-name ...
Yes, you can do this, and it's not even that hard. I have a laptop with a wireless card, and an ethernet port. I plugged a RapberryPi running Arch Linux into it, via a "crossover" ethernet cable. That's one special thing you might need - not all ethernet cards can do a machine-to-machine direct connection.
The other tricky part is IP addressing. It's best ...
My second question is - is there an easier way to configure all of this to allow simple internet access to guest os?
You don't (or, at least, shouldn't) need to manually configure anything for simple internet access; QEMU automatically handles it. It has some limitations, such as not supporting the ICMP protocol (used by ping), not being visible to the ...
A bridge is a network aggregation device, similar in practice to a switch. The bridges implemented in the Linux kernel follow this model. Like any bridge, they forward traffic based on destination MAC addresses, once the MAC address mapping is known. They are actually more featureful than most switches, since they also support firewalling, traffic shaping ...
For future readers, I wrote this email to some colleagues of mine who are working with me on configuring LXC and figuring out the bridging.
Well, I spent most of the day today fussing with networking in LXC, and now things are a lot clearer, so I thought I’d pass on what I learned.
First is a couple of definitions so we know what we’re looking at (I didn’...
You shouldn't need to set the ip_forward = 1 unless the interface is acting as a NAT for the other devices, which shouldn't be the case if you've set them up as a bridge.
Here's my KVM server setup which has a bridge device, br0, with the physical ethernet device, eth0 + all the interfaces for the KVM guests.
$ brctl show
bridge name bridge id ...
Bonding happens at a lower level than bridging. So, to get them to work together, you would take physical interfaces and bond them together, then take the bonded (virtual interface) and bridge that together with other interfaces. The other way around (bonding on top of bridging) doesn't make any sense.
Bonding lets you aggregate multiple ...
I created a Hotspot with the GNOME Network-Manager. The problem was, that I can not configure the SSID and password in GUI. If you create the Hotspot with the Network-Manager GUI, it creates the file /etc/NetworkManager/system-connections/Hotspot. In that file it is possible to edit the SSID and the password.
sudo vim /etc/NetworkManager/system-connections/...
Multicast may represent a heavy load for switch-routers (not mentioning the security aspect with potential DoS attacks). On a switch (or a Linux bridge), Multicast snooping sits at network layer 2.5 and is intended to alleviate the load by:
snooping the network traffic
identifying the multicast channels that each switch port is subscribed to
filtering out ...
When using br0 for multicasting, it needs to have IGMP Querier enabled. When it is enabled IGMP protocol version will change from v3 into v2 and it will start issuing Membership queries and no longer drop.
From what I've googled, there seems to be no utility for enabling querier on a bridge, it must be done via /sys like this:
$ echo -n 1 > /sys/devices/...
Not a problem, it's the way most openWRT systems connect the wlan and switch ports into the same LAN. Here's an example of the config on my openWRT system which has two wifi networks, one for private use and one for guests:
# brctl show
bridge name bridge id STP enabled interfaces
br-vlan2 7fff.a0f3c15eb708 no ...
The two options are similar.
This sets up your device so that it bridges traffic between the ethernet interface and the wireless interface. Nothing more. Nothing less. Your ethernet interface needs to be connected back to the rest of your network so that wireless devices connecting to the Access Point can see your network. If you have multiple ...