Hi Michal Thank you for the clarification. Also I am sorry for being a bit salty. I will look more into the linux kernel bridge module. Best Regards On Wed, 26 Oct 2022, 09:10 Michal Prívozník, <mprivozn@redhat.com> wrote:
On 10/25/22 17:03, Armin Lepir wrote:
Hi
I am using libvrt for the first time. Im building a KVM for multiple Virtual OS instances.
The problem i have is with your official documentation for Virtual Networking.
https://wiki.libvirt.org/page/VirtualNetworking <https://wiki.libvirt.org/page/VirtualNetworking>
Please note that our wiki page is obsolete and we tried to move everything into our knowledge base articles:
We're keeping the wiki around though, because maybe not everything was moved.
The following is wrong:
The default mode is BRIDGE + NAT.
Optional mode is ROUTING.
It should be:
The default mode is ROUTING + NAT.
Optional mode is BRIDGE.
As far as i know a bridge operates on the Layer2.
IP and NAT operate on the Layer3.
NAT can not operate on the L2.
Please tell me that im wrong and explain how am i wrong.
If we'd be talking about bare metal network components then you are 100% correct. Except, the Linux bridge is more than just plain L2 bridge. It can have an IP address, route traffic, serve as network interface (when a host is sending a packet to a guest, the packet is injected into said bridge).
What the wiki page is trying to say, that by default you'll get this 'default' network which uses this Linux 'bridge' + NAT. Optionally, you can define new network, or modify the existing one to switch to so called routed mode.
Hope this clears things up.
Michal