I am running KVM on 64 bit Ubuntu 10.04 Lucid with an AMD processor that has the svn flag.

I have read a few different guides on KVM and networking in Lucid including this one : https://help.ubuntu.com/community/KVM/Networking

However, they all seem to focus on bridged networking. I need guest to guest networking.

I open the KVM virt-manager->Edit->Host Details->Virtual Networks->Add button.

First page is a banner page->Forward.
Network Name: LocalLan->Forward.
Enable DHCP: checked; Start:; End:>Forward.
Isolated virtual network: selected->Forward.
Summary page->Finish.

"Error creating virtual network: cannot create bridge 'virbr0': Operation not permitted"

Fine. I will launch it with sudo. Except the sudo virt-manager launches a completely different session. I can't see my virtual machines in it and the network I created there isn't seen by my user mode virt-manager.

Does anyone know what change I need to make to allow the user mode virt-manager to create the virbr0?