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編輯

tag-icon • tag-icon networking virtualization kvm-virtualization centos7 host
編輯

我花了幾天時間尋找答案，任何配置都適合我設定網路工作。

我有 CentOS 7 (10.120.0.57）並安裝了 KVM。我創建了簡單的訪客（10.120.0.58）也使用 CentOS7 的虛擬機，但我在來賓上的網路有一些問題。主機可以存取互聯網，並且可以 ping 通訪客電腦。來賓也可以 ping 主機，但是當它 ping 其他 IP 時，它會得到：目的地無法到達。我提前在兩台機器上停用了firewalld和selinux以消除問題。

我的主機橋應該傳遞流量，因為我設定了 /etc/sysctl.conf （!!!）

net.ipv4.ip_forward = 1
net.ipv4.conf.all.proxy_arp = 1

在主機上tcp轉儲當我嘗試 ping 網路的真實網關（10.120.0.1）

IP 10.120.0.58 > gateway: ICMP echo request, id 3716, seq 1, length 64
IP 10.120.0.58 > gateway: ICMP echo request, id 3716, seq 2, length 64

如果我從訪客處 ping，例如 google.com (來自主機的 tcpdump）：

 IP localhost.localdomain > 10.120.0.58: ICMP localhost.localdomain udp port domain unreachable, length 64
 IP localhost.localdomain > 10.120.0.58: ICMP localhost.localdomain udp port domain unreachable, length 64

當然，當我 ping 訪客 (10.120.0.58)<=> 主機(10.120.0.57）：

10.120.0.58 > localhost.localdomain: ICMP echo request, id 3719, seq 8, length 64
localhost.localdomain > 10.120.0.58: ICMP echo reply, id 3719, seq 8, length 64

有人可以告訴我我的主機/來賓配置有問題嗎？

主持人： ifconfig -a：

br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.120.0.57  netmask 255.255.255.0  broadcast 10.120.0.255
        inet6 fe80::20c:29ff:fed5:14fa  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:d5:14:fa  txqueuelen 1000  (Ethernet)
        RX packets 74849  bytes 6444652 (6.1 MiB)
        RX errors 0  dropped 100  overruns 0  frame 0
        TX packets 1033  bytes 88046 (85.9 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eno16780032: flags=4419<UP,BROADCAST,RUNNING,PROMISC,MULTICAST>  mtu 1500
        inet6 fe80::20c:29ff:fed5:14fa  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:d5:14:fa  txqueuelen 1000  (Ethernet)
        RX packets 2975  bytes 239252 (233.6 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 164  bytes 23286 (22.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1  (Local Loopback)
        RX packets 6  bytes 644 (644.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 6  bytes 644 (644.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 52:54:00:9f:de:66  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0-nic: flags=4098<BROADCAST,MULTICAST>  mtu 1500
        ether 52:54:00:9f:de:66  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

vnet0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        ether fe:54:00:7f:c5:c5  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 5885 overruns 0  carrier 0  collisions 0

vnet1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        ether fe:54:00:b0:3d:40  txqueuelen 1000  (Ethernet)
        RX packets 420  bytes 34697 (33.8 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 111762  bytes 9374955 (8.9 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

br0配置：

DEVICE=br0
BOOTPROTO=static
TYPE=Bridge
ONBOOT=yes
IPADDR="10.120.0.57"
NETMASK="255.255.255.0"
#GATEWAY="10.120.0.1"
#DNS1="10.120.0.1"
#DNS2="8.8.8.8"
STP=yes
DELAY=0
NM_CONTROLLED=no

eno16780032配置：

TYPE="Ethernet"
#NAME="eno16780032"
#UUID="4fc9740c-536a-4330-aab4-bdef7489582f"
DEVICE="eno16780032"
ONBOOT="yes"
NM_CONTROLLED=no
BRIDGE=br0

橋：

bridge name     bridge id               STP enabled     interfaces
br0             8000.000c29d514fa       yes             eno16780032
                                                        vnet0
                                                        vnet1
virbr0          8000.5254009fde66       yes             virbr0-nic

主機/etc/sysconfig/network：

# Created by anaconda
NETWORKING=yes
GATEWAY=10.120.0.1

訪客eth0配置：

DEVICE=eth0
NAME=eth0
TYPE=Ethernet
BOOTPROTO=static
ONBOOT=yes
IPADDR="10.120.0.58"
NETMASK="255.255.255.0"
GATEWAY="10.120.0.57" (!?)
DNS1="10.120.0.57"
DNS2="8.8.8.8"

預先感謝您的瀏覽。

編輯

我新增來自主機的 iptables 結果：

[root@localhost ~]# iptables -L -v -n -t nat
Chain PREROUTING (policy ACCEPT 59 packets, 4981 bytes)
 pkts bytes target     prot opt in     out     source               destination 

Chain INPUT (policy ACCEPT 34 packets, 3619 bytes)
 pkts bytes target     prot opt in     out     source               destination 

Chain OUTPUT (policy ACCEPT 2 packets, 103 bytes)
 pkts bytes target     prot opt in     out     source               destination 

Chain POSTROUTING (policy ACCEPT 2 packets, 103 bytes)
 pkts bytes target     prot opt in     out     source               destination

來自訪客的 iptables：

[root@localhost ~]# iptables -L -v -n -t nat
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

來自訪客的追蹤路徑（10.120.0.58) 至 8.8.8.8：

 1?: [LOCALHOST]                                         pmtu 1500
 1:  10.120.0.58                                         3012.516ms !H
                   Resume: pmtu 1500

編輯2

我加iptables -L -v -n結果。來自主持人：

[root@localhost ~]# iptables -L -v -n
Chain INPUT (policy ACCEPT 162K packets, 17M bytes)
 pkts bytes target     prot opt in     out     source               destination 

Chain FORWARD (policy ACCEPT 8 packets, 476 bytes)
 pkts bytes target     prot opt in     out     source               destination 

Chain OUTPUT (policy ACCEPT 3894 packets, 309K bytes)
 pkts bytes target     prot opt in     out     source               destination

來自客人：

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

Chain FORWARD (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

答案1

由於您將主機的實體設備與虛擬機器橋接（我猜vnet0和/或是vnet1用於虛擬機器的設備），因此您可以實體存取10.120.0.0/24虛擬機器內的網路。
所以你應該更換

GATEWAY="10.120.0.57" (!?)
DNS1="10.120.0.57"

經過

GATEWAY="110.120.0.1"
DNS1="10.120.0.1"

答案2

我也有完全一樣的問題。它看起來像是 virtio 網路驅動程式中的一個錯誤。為了解決該問題我做了以下更改：

在 Centos 7 上 - KVM -->

  1. 在執行 KVM 的 Centos 7 上停用 NetworkManager 服務並啟用舊的「網路」服務。
  2. 在 /etc/sysconfig/network 中定義網關，並在 /etc/sysconfig/network-scripts/ifcfg-eth0 （或類似檔案）中進行所有必要的變更。設定IPADDR、NETMASK等
  3. 更改來賓電腦的虛擬網路驅動程式（透過 virt-manager）。將其設為“e1000”

在您的客人上 -->

  1. 完全一樣。停用 NetworkManager 並啟用網路服務。
  2. 此變更可能會影響網路介面名稱，因此請使用指令 #cat /proc/net/dev (centos guest) 檢查新名稱

以上對我有用。我花了一個多星期才找到解決方案。

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