Hi Dan,
I try the following way :-
1. I placed your script in the following location :- /usr/libexec/vdsm/hooks/before_device_create/50_noipspoof & /usr/libexec/vdsm/hooks/before_nic_hotplug/50_noipspoof
2. Then run this command on the ovirt-engine server (engine-config -s "UserDefinedVMProperties=noipspoof=^[0-9.]*$")
3. After that stop the VM and set a custom property named "noipspoof" with ip 10.10.10.6.
4. Run the VM and login via ssh,configure another ethernet with eth0:0 with the ip address 10.10.10.9
5. From another VM with ip 10.10.10.5 i can able to ping 10.10.10.9....
One strange thing is in VM xml still the filter is "vdsm-no-mac-spoofing" instead of "noipspoof"
----------------
<interface type='bridge'>
<mac address='00:1a:4a:81:80:09'/>
<source bridge='private'/>
<target dev='vnet0'/>
<model type='virtio'/>
<filterref filter='vdsm-no-mac-spoofing'/>
<link state='up'/>
<alias name='net0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/ >
----------------
Please let me know if i am wrong here....