#!/bin/sh                                                         
                                                                  
ifname=`ifconfig epair create`                                    
epair=`echo ${ifname%a}`                                          
jail -c name=alcatraz persist vnet vnet.interface=${epair}b       
                                                                  
ifconfig ${epair}a name foo                                       
jexec alcatraz ifconfig ${epair}b name bar                        
                                                                  
jail -r alcatraz                                                  
ifconfig foo destroy