[root@server dnsmasq-2.38]# virsh --connect=qemu:///session net-start default
error: failed to get network 'default'

[root@server dnsmasq-2.38]# ps aux  | grep libvirt
root     18736  0.0  0.2   3304  1228 ?        S    21:54   0:00 libvirt_qemud --system --daemon
root     18761  0.0  0.0      0     0 ?        Z    21:54   0:00 [libvirt_qemud] <defunct>
root     18815  0.0  0.1   3356   876 ?        S    21:57   0:00 /usr/local/sbin/libvirt_qemud --timeout 30
root     18818  0.0  0.1   3884   700 pts/1    S+   21:57   0:00 grep libvirt
[root@server dnsmasq-2.38]#