I have a network, let's say 192.168.0.0/24, and two servers 192.168.0.1 and 192.168.0.2. On this same network I have a wokstation, lets call it 192.168.0.100 which is running libvirt using qemu for the emultation. This workstation has a network device called br0 which has the ip address 192.168.0.100 and when I try to create an isolated network which is also on the 192.168.0.0/24 range I get an error stating that this range is already in use on the host. I need to be able to recreate an absolutely isolated network in the 192.168.0.0/24 range to be able to copy the servers 192.168.0.1 and 192.168.0.2 in here and perform the tests I need.

On Tuesday, September 17th, 2024 at 11:07, Alvin Starr via Users <users@lists.libvirt.org> wrote:

On 2024-09-17 08:05, bd730c5053df9efb via Users wrote:
Hi all!

I have a question about networking and haven't been able to find it online. I need to replicate a server installation in a host to be able to test a procedure but the host is on the same network as the servers so I am not being able to create an isolated network on the host because there is an interface in the same range of ip adresses. Is there any way to create this isolated virtual network without it conflicting with the hosts network?
my quick guess is that you have created a copy of the VM with identical MAC addresses for the NIC.
Each NIC on your network needs to have a unique MAC address.

There are a few tools to generate random MAC addresses.
Grab one of these and then just change the mac address in the clone VM.
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Alvin Starr                   ||   land:  (647)478-6285
Netvel Inc.                   ||   home:  (905)513-7688
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