When I try using vncviewer to remote access a libvirt virtual machine, it shows error:

VNC Viewer Free Edition 4.1.1 for X - built Apr  2 2015 21:51:06
Copyright (C) 2002-2005 RealVNC Ltd.
See http://www.realvnc.com for information on VNC.

Wed Dec 16 11:24:12 2015
 main:        unable to connect to host: Connection refused (111)

I had a wierd situation recently, could get the ip address, set up apt.conf and proxy correctly, but could not connect network, could ping a inner desttop, then my friend found that it responses twice when ping this ip, so it probably is that the ip is used by other people stactly, so I need to get a new automatic ip address, here is what I did,

1. vim /etc/ssh/sshd_config

Change the setting PrintLastLog to "no"

Change the setting PermitRootLogin to "yes"

2. vim /etc/motd

Change the content to what you want.

3. service sshd restart or  /etc/init.d/ssh restart

OVMF, open virtual machine firmware, is project from EDK-II which to support UEFI for virtual machines. It contains a sample firmware for QEMU and KVM