How to: Libvirt Port forwarding

 net.ipv4.ip_forward 

#!/bin/bash

# IMPORTANT: Change the "VM NAME" string to match your actual VM Name. 
# In order to create rules to other VMs, just duplicate the below block and configure
# it accordingly.
if [ "${1}" = "VM NAME" ]; then  

   # Update the following variables to fit your setup
   GUEST_IP=
   GUEST_PORT=
   HOST_PORT=

   if [ "${2}" = "stopped" ] || [ "${2}" = "reconnect" ]; then  
	/sbin/iptables -D FORWARD -o virbr0 -d  $GUEST_IP -j ACCEPT
	/sbin/iptables -t nat -D PREROUTING -p tcp --dport $HOST_PORT -j DNAT --to $GUEST_IP:$GUEST_PORT
   fi
   if [ "${2}" = "start" ] || [ "${2}" = "reconnect" ]; then  
	/sbin/iptables -I FORWARD -o virbr0 -d  $GUEST_IP -j ACCEPT
	/sbin/iptables -t nat -I PREROUTING -p tcp --dport $HOST_PORT -j DNAT --to $GUEST_IP:$GUEST_PORT
   fi
fi

 chmod +x /etc/libvirt/hooks/qemu