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 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. Best Regards
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Please note that our wiki page is obsolete and we tried to move everything into our knowledge base articles: https://libvirt.org/kbase/ We're keeping the wiki around though, because maybe not everything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
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
participants (2)
-
Armin Lepir -
Michal Prívozník