备注：以下方法使用vde2 switch设置成一个hub来使用，解决了GUEST之间无法正常通信的问题。
# pkg install vde2
# vim /etc/rc.conf
########## HOST can access GUEST, GUEST can access HOST, GUEST can access GUEST.
cloned_interfaces="tap0 em0 bridge0"
ifconfig_bridge0="addm em0 addm tap0 up"
/usr/local/bin/vde_switch -d -x -s /tmp/vde1 -M /tmp/mgmt1 -tap tap0 -m 660 -g wheel --mgmtmode 660 --mgmtgroup wheel
# vim /boot/loader.conf
bridge_load="YES"
if_tap_load="YES"
if_bridge_load="YES"
bridgestp_load="YES"
# vim /etc/devfs.conf
own tap0 root:wheel
perm tap0 660
# vim /etc/sysctl.conf
net.link.tap.user_open=1
net.link.tap.up_on_open=1
net.inet.ip.forwarding=1
# cat /data/vm/zabbix_test/start.sh
#!/usr/local/bin/bash
#### use the vde2 switch, how to connect the vde2 switch: vdeterm /tmp/mgmt1
/usr/local/bin/qemu-system-x86_64 -smp 8 -m 2048 -hda /data/vm/zabbix_test/zabbix_test.img \
-net nic,model=e1000 -net vde,sock=/tmp/vde1 \
-rtc base=localtime -vnc 192.168.1.107:11 -boot c
# cat /data/vm/mail_doleimi_com/start.sh
#!/usr/local/bin/bash
#### use the vde2 switch, how to connect the vde2 switch: vdeterm /tmp/mgmt1
/usr/local/bin/qemu-system-x86_64 -smp 8 -m 5120 -hda /data/vm/mail_doleimi_com/mail_doleimi_com.img \
-net nic,model=e1000 -net vde,sock=/tmp/vde1 \
-rtc base=localtime -vnc 192.168.1.107:12 -boot c
# cat /data/vm/ftp.blueflag-software.com.cn/start.sh
#!/usr/local/bin/bash
#### use the vde2 switch, how to connect the vde2 switch: vdeterm /tmp/mgmt1
/usr/local/bin/qemu-system-x86_64 -smp 8 -m 1024 -hda /data/vm/ftp.blueflag-software.com.cn/ftp.blueflag-software.com.cn.img \
-net nic,model=e1000 -net vde,sock=/tmp/vde1 \
-rtc base=localtime -vnc 192.168.1.107:13 -boot c