宿主机:Red Hat Enterprise Linux Server release 7.3 
kvm 虚拟机使用桥接网络
宿主机网络配置:
cat ifcfg-ens192BOOTPROTO=none
DEVICE=ens192
NM_CONTROLLED=no
ONBOOT=yes
BRIDGE=br0
-----------------------------------------------------------------------------------------------
cat ifcfg-br0 BOOTPROTO=static
DEVICE=br0
TYPE=Bridge
NM_CONTROLLED=no
IPADDR=192.168.1.214
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
DEFROUTE=yes
PEERDNS=yes
PEERROUTES=yes
ONBOOT=yes
-----------------------------------------------------------------------------------------------
虚拟机网络配置
cat /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=eth0
TYPE=Ethernet
ONBOOT=yes
NM_CONTROLLED=no
BOOTPROTO=none
IPADDR=192.168.1.215
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
-----------------------------------------------------------------------------------------------
brctl show
bridge name bridge id STP   enabled interfaces
br0 8000.0050568cdf22 no                 ens192
                                                                    vnet0
-----------------------------------------------------------------------------------------------
virsh list
 Id    Name                           State
----------------------------------------------------
 1     centos6.6                      running
-----------------------------------------------------------------------------------------------
virsh edit centos6.6<interface type='bridge'>
      <mac address='52:54:00:d6:7e:cc'/>
      <source bridge='br0'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
-----------------------------------------------------------------------------------------------
cat /proc/sys/net/ipv4/ip_forward
1
-----------------------------------------------------------------------------------------------
物理机route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         gateway         0.0.0.0         UG    0      0        0 br0
link-local      0.0.0.0         255.255.0.0     U     1003   0        0 br0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 br0
-----------------------------------------------------------------------------------------------
 虚拟机route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.0     *               255.255.255.0   U     0      0        0 eth0
link-local      *               255.255.0.0     U     1002   0        0 eth0
default         192.168.1.1     0.0.0.0         UG    0      0        0 eth0
-----------------------------------------------------------------------------------------------
问题现象描述:
宿主机IP 192.168.1.214 
虚拟机IP 192.168.1.215    手动设置
宿主机可以ping通网关可以通外网可ping通虚拟机
虚拟机可以ping通宿主机无法ping通网关及外网