KVM Ubuntu Guest无法在桥接网络上连接到Internet

我有Ubuntu 14.04(64位)KVM主机和2个NIC：
– eth0连接到“公共”网络
– eth1通过私有IP地址范围连接到br0网桥

从主机我可以访问互联网,ping VM Guest并通过SSH连接到它.
从VM Guest我只能ping主机,但无法访问Internet而无法ping google.com

请帮助我在下面的设置中将VM Guest连接到互联网：

在主持人：

的/ etc /网络/接口

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
  address 192.168.2.60
  netmask 255.255.255.0
  gateway 192.168.2.254
  dns-nameservers 8.8.8.8

auto eth1
iface eth1 inet manual

auto br0
iface br0 inet static
  address 10.0.0.1
  netmask 255.255.255.0
  bridge_ports    eth1
  bridge_stp      off
  bridge_maxwait  0
  bridge_fd       0

 # Create and destroy the bridge automatically.
pre-up brctl addbr br0
ip link set dev br0 up
post-up /usr/sbin/brctl setfd br0 0 addif br0 eth1
post-down brctl delbr br0

KVM网络定义为：

<network>
<name>br0-net</name>
<uuid>9d24b473-0b4d-4cfa-8b12-7bf267d856ae</uuid>
<forward mode='bridge'/>
<bridge name='br0'/>
</network>

#sysctl -p /etc/sysctl.conf

 net.ipv4.ip_forward = 1
 net.bridge.bridge-nf-call-ip6tables = 0
 net.bridge.bridge-nf-call-iptables = 0
 net.bridge.bridge-nf-call-arptables = 0

#route -n

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.2.254   0.0.0.0         UG    0      0        0 eth0
10.0.0.0        0.0.0.0         255.255.255.0   U     0      0        0 br0
192.168.2.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0

#iptables -t nat -vnL

Chain PREROUTING (policy ACCEPT 0 packets,0 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain INPUT (policy ACCEPT 0 packets,0 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain OUTPUT (policy ACCEPT 0 packets,0 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain POSTROUTING (policy ACCEPT 0 packets,0 bytes)
 pkts bytes target     prot opt in     out     source               destination

在VM Guest：

的/ etc /网络/接口

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
  address 10.0.0.11
  netmask 255.255.255.0

Guest xml定义为

<interface type='bridge'>
<mac address='52:54:00:6b:93:69'/>
<source bridge='br0'/>
<model type='virtio'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
</interface>

#route -n

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.0.0.1        0.0.0.0         UG    0      0        0 eth0
10.0.0.0        0.0.0.0         255.255.255.0   U     0      0        0 eth0

#iptables -t nat -vnL

Chain PREROUTING (policy ACCEPT 0 packets,0 bytes)
 pkts bytes target     prot opt in     out     source               destination

来自Guest的Ping KVM主机适用于10.0.0.1和192.168.2.60：

$ping 10.0.0.1

PING 10.0.0.1 (10.0.0.1) 56(84) bytes of data.
64 bytes from 10.0.0.1: icmp_seq=1 ttl=64 time=0.555 ms

$ping 192.168.2.60

PING 192.168.2.60 (192.168.2.60) 56(84) bytes of data.
64 bytes from 192.168.2.60: icmp_seq=1 ttl=64 time=0.772 ms

从Guest ping另一台计算机192.168.2.3不起作用：

--- 192.168.2.3 ping statistics ---
277 packets transmitted,0 received,100% packet loss,time 276399ms

来自Guest的ping google.com不起作用：

ping: unkNown host google.com

我认为你错过了假面舞会的iptable规则

iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -o eth0 -j MASQUERADE

原文地址：https://www.jb51.cc/ubuntu/347543.html