(added users@lists.libvirt.org back into the Cc so that anyone else asking the same question in the future will benefit from the answer) On 3/28/25 8:12 AM, James Liu wrote:

Hi Laine,

I tried your first solution but somehow it didn't work(the network is NAT). I edited the xml in virt-manager gui. Whenever I added following options, and click "Apply", the virt-manager will revert(remove) the "alias" tag;  consequently, the qemu command line couldn't find the device name('foo' in this example).

Sorry, I had meant to point this out but somehow forgot - user-specified aliases must begin with "ua-", otherwise they will be ignored. So instead of using "<alias name='foo'/>", use "<alias name='ua-foo'/>" (and then in the <qemu:arg value> use "netdev=hostua-foo") Also note that your guest should be shutdown while you're making these changes.

Appreciate your suggestions.

<interface type="network">   <mac address="52:54:00:3a:bf:52"/>   <source network="default"/>   <model type="e1000e"/>    <alias name="*foo*"/>            # virt-manager will always remove this tag    <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>   </interface>

  <qemu:commandline>     <qemu:arg value="-object"/>     <qemu:arg value="filter-dump,id=f1,netdev=*foo*,file=/tmp/xyzzy.pcap"/>   </qemu:commandline>