無法從橋接介面 ping

我正在嘗試 在虛擬框中架起 Ubuntu 11.04之間eth2的橋樑。br0有主機物理機的網路橋接。

從橋接後的來賓作業系統我可以 ping 從br0 但不能從eth2. 為什麼？

ping -I eth2 bbc.co.uk:

PING bbc.co.uk (212.58.241.131) from 172.16.4.186 eth2: 56(84) bytes of data.
From VirtualBox.local (172.16.4.103) icmp_seq=2 Destination Host Unreachable
From VirtualBox.local (172.16.4.103) icmp_seq=3 Destination Host Unreachable

ping -I br0 bbc.co.uk

PING bbc.co.uk (212.58.241.131) from 172.16.4.186 br0: 56(84) bytes of data.
64 bytes from virtual-vip.thdo.bbc.co.uk (212.58.241.131): icmp_req=1 ttl=239 time=31.2 ms

我的 /etc/network/interfaces如下

auto lo
iface lo inet loopback

auto eth2
iface eth2 inet manual

auto br0
iface br0 inet static
       address 172.16.4.186
       network 172.16.4.255
       netmask 255.255.255.0
       broadcast 172.16.4.255
       gateway 172.16.4.1
       bridge_ports eth2
       bridge_stp off
       bridge_fd 0
       bridge_maxwait 0

網關是

route -n

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.16.4.1      0.0.0.0         UG    100    0        0 br0
172.16.4.0      0.0.0.0         255.255.255.0   U     0      0        0 br0
172.16.4.0      0.0.0.0         255.255.255.0   U     1      0        0 eth3

ifconfig

br0       Link encap:Ethernet  HWaddr 08:00:27:4a:08:57  
         inet addr:172.16.4.186  Bcast:172.16.4.255  Mask:255.255.255.0
         inet6 addr: fe80::a00:27ff:fe4a:857/64 Scope:Link
         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         RX packets:2969 errors:0 dropped:0 overruns:0 frame:0
         TX packets:267 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:0 
         RX bytes:200777 (200.7 KB)  TX bytes:28141 (28.1 KB)

eth0      Link encap:Ethernet  HWaddr 08:00:27:df:f5:a7  
         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         RX packets:36 errors:0 dropped:0 overruns:0 frame:0
         TX packets:392 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:1000 
         RX bytes:3904 (3.9 KB)  TX bytes:55700 (55.7 KB)

eth2      Link encap:Ethernet  HWaddr 08:00:27:4a:08:57  
         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         RX packets:19849 errors:0 dropped:0 overruns:0 frame:0
         TX packets:1206 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:1000 
         RX bytes:1631595 (1.6 MB)  TX bytes:114927 (114.9 KB)

eth3      Link encap:Ethernet  HWaddr 08:00:27:50:00:2d  
         inet addr:172.16.4.103  Bcast:172.16.4.255  Mask:255.255.255.0
         inet6 addr: fe80::a00:27ff:fe50:2d/64 Scope:Link
         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         RX packets:19515 errors:0 dropped:0 overruns:0 frame:0
         TX packets:145 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:1000 
         RX bytes:1625905 (1.6 MB)  TX bytes:17450 (17.4 KB)

lo        Link encap:Local Loopback  
         inet addr:127.0.0.1  Mask:255.0.0.0
         inet6 addr: ::1/128 Scope:Host
         UP LOOPBACK RUNNING  MTU:16436  Metric:1
         RX packets:113 errors:0 dropped:0 overruns:0 frame:0
         TX packets:113 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:0 
         RX bytes:12544 (12.5 KB)  TX bytes:12544 (12.5 KB)

這是預期的行為。如果將 eth2 連接到網橋，則 eth2 將無法使用（即使使用 IP 地址）。您在軟體方面使用 br0， eth0 在物理上使用。

一般來說，在談論橋樑時，給出輸出是有意義的brctl show

介面上沒有ipaddress eth2。

這也是問題所在。

引用自：https://serverfault.com/questions/478453