我正在嘗試將 KVM 來賓（Ubuntu 18.04）添加到本地網絡，就像網絡中的其他真實伺服器一樣。我在主機系統（Ubuntu 18.04）中配置了 KVM 橋接口，並且連接正常。主機系統可透過本機網路存取其他伺服器。
主機系統的 netplan 設定：
$ cat 01-netcfg.yaml
# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
version: 2
renderer: networkd
ethernets:
eno1:
dhcp4: false
bridges:
br0:
interfaces: [eno1]
addresses: [192.168.1.105/24]
gateway4: 192.168.1.1
nameservers:
addresses: [x.x.x.x, x.x.x.x]
dhcp4: false
ip a顯示橋樑介面的輸出：
10697: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 62:cb:37:3c:c0:70 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.105/24 brd 192.168.1.255 scope global br0
valid_lft forever preferred_lft forever
inet6 fe80::60cb:37ff:fe3c:c070/64 scope link
valid_lft forever preferred_lft forever
我使用網橋 br0 建立了 KVM 網路介面
virsh net-edit br0輸出：
<network>
<name>br0</name>
<uuid>d277e3d1-b34e-4b1f-ae69-6a3c8f75626c</uuid>
<forward mode='bridge'/>
<bridge name='br0'/>
</network>
developer@serv31:~$ virsh net-list
Name State Autostart Persistent
----------------------------------------------------------
br0 active yes yes
default active yes yes
KVM來賓域的介面資訊：
<interface type='network'>
<mac address='52:54:00:14:dc:af'/>
<source network='br0'/>
<model type='rtl8139'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</interface>
在來賓虛擬機器中，我配置了 netplan 為其提供靜態 IP。它確實使用配置的 IP 啟動。
$ cat 50-cloud-init.yaml
network:
version: 2
ethernets:
ens3:
addresses: [192.168.1.50/24]
gateway4: 192.168.1.1
nameservers:
addresses: [x.x.x.x, x.x.x.x]
dhcp4: false
來賓虛擬機器ip a輸出：
$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 52:54:00:14:dc:af brd ff:ff:ff:ff:ff:ff
inet 192.168.1.50/24 brd 192.168.1.255 scope global ens3
valid_lft forever preferred_lft forever
inet6 fe80::5054:ff:fe14:dcaf/64 scope link
valid_lft forever preferred_lft forever
來賓虛擬機能夠存取（ping、telnet）主機系統，主機系統可以存取來賓虛擬機器。但網路中沒有其他伺服器可以存取來賓虛擬機，而且來賓虛擬機也無法存取網際網路。請幫我解決這個問題。如果您需要更多信息，請告訴我。
編輯 ：
ip link輸出 ：
:~$ ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master br0 state UP mode DEFAULT group default qlen 1000
link/ether 00:21:9b:9a:f2:be brd ff:ff:ff:ff:ff:ff
3: eno2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ether 00:21:9b:9a:f2:c0 brd ff:ff:ff:ff:ff:ff
4: eno3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ether 00:21:9b:9a:f2:c2 brd ff:ff:ff:ff:ff:ff
5: eno4: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ether 00:21:9b:9a:f2:c4 brd ff:ff:ff:ff:ff:ff
6: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default
link/ether 02:42:b3:0f:d6:24 brd ff:ff:ff:ff:ff:ff
9: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
link/ether 52:54:00:56:08:1e brd ff:ff:ff:ff:ff:ff
10: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master virbr0 state DOWN mode DEFAULT group default qlen 1000
link/ether 52:54:00:56:08:1e brd ff:ff:ff:ff:ff:ff
19219: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master br0 state UNKNOWN mode DEFAULT group default qlen 1000
link/ether fe:54:00:14:dc:af brd ff:ff:ff:ff:ff:ff
8744: vnet1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master virbr0 state UNKNOWN mode DEFAULT group default qlen 1000
link/ether fe:54:00:6f:20:0f brd ff:ff:ff:ff:ff:ff
10950: vnet2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master virbr0 state UNKNOWN mode DEFAULT group default qlen 1000
link/ether fe:54:00:c1:0e:86 brd ff:ff:ff:ff:ff:ff
10697: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
link/ether 62:cb:37:3c:c0:70 brd ff:ff:ff:ff:ff:ff
10971: vnet3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master br0 state UNKNOWN mode DEFAULT group default qlen 1000
link/ether fe:54:00:a4:13:1c brd ff:ff:ff:ff:ff:ff
包含 virbr0 和 br0 的 iptable 規則
:~$ sudo iptables-save | grep br0
-A POSTROUTING -o virbr0 -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill
-A POSTROUTING -o br0 -j MASQUERADE
-A INPUT -i virbr0 -p udp -m udp --dport 53 -j ACCEPT
-A INPUT -i virbr0 -p tcp -m tcp --dport 53 -j ACCEPT
-A INPUT -i virbr0 -p udp -m udp --dport 67 -j ACCEPT
-A INPUT -i virbr0 -p tcp -m tcp --dport 67 -j ACCEPT
-A FORWARD -d 192.168.122.0/24 -o virbr0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -s 192.168.122.0/24 -i virbr0 -j ACCEPT
-A FORWARD -i virbr0 -o virbr0 -j ACCEPT
-A FORWARD -o virbr0 -j REJECT --reject-with icmp-port-unreachable
-A FORWARD -i virbr0 -j REJECT --reject-with icmp-port-unreachable
-A FORWARD -i br0 -o virbr0 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -i virbr0 -o br0 -j ACCEPT
-A OUTPUT -o virbr0 -p udp -m udp --dport 68 -j ACCEPT
答案1
sudo iptables -t nat -A POSTROUTING -o br0 -j MASQUERADE
sudo iptables -A FORWARD -i br0 -o virbr0 -m state --state RELATED,ESTABLISHED -j ACCEPT
sudo iptables -A FORWARD -i virbr0 -o br0 -j ACCEPT
sudo iptables -I FORWARD 1 -i br0 -o br0 -j ACCEPT
上述規則解決了問題。