[Qemu-discuss] How to change default network address spacces?

[Tony Su]

Hello,

I need to change the default address spaces for virtual networks,
particularly for User Mode Networking since a network this laptop
frequently connects to recently changed its address space to the Class
A Private Network using the default subnet mask (which means that only
one networkID is supported so no other network also using the Class A
Private network address space can route.

System: x64 openSUSE 12.2
QEMU emulator version 1.1.1 (kvm-1.1.1-1.8.1

Believe the following command should have changed the address space to
a Class B Private Network, but the command tries to launch an empty
VM. Have tried running with the libvirtd service running then
restarting and also stopping the service before running the command,
and of course also with a reboot.

# qemu-kvm -net user,net=176.27.0.0/12,host=176.27.2.2,dhcpstart=176.27.0.20

Unable to determine my command simply contains a syntax error, or if I
should be running a different command.

Note, I have some success creating new virtual networks using
virt-manager but only if not connected to this problem physical
network. It seems that if there is a conflict with the default address
spaces, QEMU-KVM networking is rendered inoperable so I need to make a
change to the default address spaces used and make the changes
persistent.

TIA,
TSU