KVM桥接网卡

一、网卡配置

　　1、nat转换，kvm 网卡配置默认安装虚拟机是nat

二、基本查看命令

　　查看宿主机网卡：

[root@centoszhu opt]# ifconfig
ens33: flags=4163 mtu 1500inet 192.168.207.133 netmask 255.255.255.0 broadcast 192.168.207.255inet6 fe80::42dc:4fac:357f:ed9c prefixlen 64 scopeid 0x20ether 00:0c:29:84:c4:39 txqueuelen 1000 (Ethernet)RX packets 7270 bytes 899317 (878.2 KiB)RX errors 0 dropped 0 overruns 0 frame 0TX packets 3332 bytes 421317 (411.4 KiB)TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0lo: flags=73 mtu 65536inet 127.0.0.1 netmask 255.0.0.0inet6 ::1 prefixlen 128 scopeid 0x10loop txqueuelen 1000 (Local Loopback)RX packets 34 bytes 2744 (2.6 KiB)RX errors 0 dropped 0 overruns 0 frame 0TX packets 34 bytes 2744 (2.6 KiB)TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0virbr0: flags=4163 mtu 1500inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255ether 52:54:00:93:4c:f8 txqueuelen 1000 (Ethernet)RX packets 582 bytes 40920 (39.9 KiB)RX errors 0 dropped 0 overruns 0 frame 0TX packets 520 bytes 46710 (45.6 KiB)TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0vnet0: flags=4163 mtu 1500 第一个虚拟机的网卡inet6 fe80::fc54:ff:fe6b:ebb9 prefixlen 64 scopeid 0x20ether fe:54:00:6b:eb:b9 txqueuelen 1000 (Ethernet)RX packets 183 bytes 14700 (14.3 KiB)RX errors 0 dropped 0 overruns 0 frame 0TX packets 1350 bytes 80145 (78.2 KiB)TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0vnet1: flags=4163 mtu 1500 第二个虚拟机的网卡inet6 fe80::fc54:ff:fe96:81cd prefixlen 64 scopeid 0x20ether fe:54:00:96:81:cd txqueuelen 1000 (Ethernet)RX packets 0 bytes 0 (0.0 B)RX errors 0 dropped 0 overruns 0 frame 0TX packets 0 bytes 0 (0.0 B)TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

　　查看虚拟交换机:

[root@centoszhu opt]# brctl show
bridge name bridge id STP enabled interfaces
virbr0 8000.525400934cf8 yes virbr0-nicvnet0vnet1

　　查看内核转发参数：

[root@centoszhu opt]# sysctl -a|grep ipv4|grep forward
net.ipv4.conf.all.forwarding = 1
net.ipv4.conf.all.mc_forwarding = 0
net.ipv4.conf.default.forwarding = 1
net.ipv4.conf.default.mc_forwarding = 0
net.ipv4.conf.ens33.forwarding = 1
net.ipv4.conf.ens33.mc_forwarding = 0
net.ipv4.conf.lo.forwarding = 1
net.ipv4.conf.lo.mc_forwarding = 0
net.ipv4.conf.virbr0.forwarding = 1
net.ipv4.conf.virbr0.mc_forwarding = 0
net.ipv4.conf.virbr0-nic.forwarding = 1
net.ipv4.conf.virbr0-nic.mc_forwarding = 0
net.ipv4.conf.vnet0.forwarding = 1
net.ipv4.conf.vnet0.mc_forwarding = 0
net.ipv4.conf.vnet1.forwarding = 1
net.ipv4.conf.vnet1.mc_forwarding = 0
net.ipv4.ip_forward = 1 1为开启
net.ipv4.ip_forward_use_pmtu = 0
sysctl: reading key "net.ipv6.conf.all.stable_secret"
sysctl: reading key "net.ipv6.conf.default.stable_secret"
sysctl: reading key "net.ipv6.conf.ens33.stable_secret"
sysctl: reading key "net.ipv6.conf.lo.stable_secret"
sysctl: reading key "net.ipv6.conf.virbr0.stable_secret"
sysctl: reading key "net.ipv6.conf.virbr0-nic.stable_secret"
sysctl: reading key "net.ipv6.conf.vnet0.stable_secret"
sysctl: reading key "net.ipv6.conf.vnet1.stable_secret"[root@centoszhu opt]# sysctl net.ipv4.ip_forward=0 临时调内核参数

查看规则：

[root@centoszhu opt]# iptables -t nat -L -n
Chain PREROUTING (policy ACCEPT)
target prot opt source destination
PREROUTING_direct all -- 0.0.0.0/0 0.0.0.0/0
PREROUTING_ZONES_SOURCE all -- 0.0.0.0/0 0.0.0.0/0
PREROUTING_ZONES all -- 0.0.0.0/0 0.0.0.0/0 Chain INPUT (policy ACCEPT)
target prot opt source destination Chain OUTPUT (policy ACCEPT)
target prot opt source destination
OUTPUT_direct all -- 0.0.0.0/0 0.0.0.0/0 Chain POSTROUTING (policy ACCEPT)
target prot opt source destination
RETURN all -- 192.168.122.0/24 224.0.0.0/24
RETURN all -- 192.168.122.0/24 255.255.255.255
MASQUERADE tcp -- 192.168.122.0/24 !192.168.122.0/24 masq ports: 1024-65535
MASQUERADE udp -- 192.168.122.0/24 !192.168.122.0/24 masq ports: 1024-65535
MASQUERADE all -- 192.168.122.0/24 !192.168.122.0/24 只要是192.168.122.0段的就模拟成本机的外网地址

 三、修改虚拟机网卡为桥接

　　1、拓扑图

　　2、手动配置桥接网卡

　　　　编辑网卡配置文件

vim /etc/sysconfig/network-scripts/ifcfg-ens33TYPE=Ethernet
PROXY_METHOD=none
BROWSER_OnLY=no
BOOTPROTO=static
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCOnF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=ens33
UUID=80960b0d-54cd-41db-bb42-28d30da2afa4
DEVICE=ens33
OnBOOT=yes
BRIDGE="br0" //添加这一行，如果配置过静态ip，需要把ipaddr，gateway，netmask，dns配置删除

　　　　添加网卡配置文件

vim /etc/sysconfig/network-scripts/ifcfg-br0DEVICE="br0"
NM_COnTROLLED="yes"
OnBOOT="yes"
TYPE="Bridge"
BOOTPROTO=dhcp #这里也可以设置成静态IP

　　　　重启网卡服务

systemctl restart network

　　　　查看当前IP

ifconfig
br0: flags=4163 mtu 1500inet 192.168.10.13 netmask 255.255.255.0 broadcast 192.168.10.255inet6 fe80::20c:29ff:febe:8be8 prefixlen 64 scopeid 0x20ether 00:0c:29:be:8b:e8 txqueuelen 1000 (Ethernet)RX packets 1109336 bytes 4514990433 (4.2 GiB)RX errors 0 dropped 0 overruns 0 frame 0TX packets 984697 bytes 53197602 (50.7 MiB)TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens33: flags=4163 mtu 1500ether 00:0c:29:be:8b:e8 txqueuelen 1000 (Ethernet)RX packets 3280291 bytes 4647765745 (4.3 GiB)RX errors 0 dropped 0 overruns 0 frame 0TX packets 984898 bytes 59123703 (56.3 MiB)TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73 mtu 65536inet 127.0.0.1 netmask 255.0.0.0inet6 ::1 prefixlen 128 scopeid 0x10loop txqueuelen 1000 (Local Loopback)RX packets 0 bytes 0 (0.0 B)RX errors 0 dropped 0 overruns 0 frame 0TX packets 0 bytes 0 (0.0 B)TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0virbr0: flags=4099 mtu 1500inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255ether 52:54:00:67:94:c0 txqueuelen 1000 (Ethernet)RX packets 0 bytes 0 (0.0 B)RX errors 0 dropped 0 overruns 0 frame 0TX packets 0 bytes 0 (0.0 B)TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0vnet0: flags=4163 mtu 1500inet6 fe80::fc54:ff:fed1:8167 prefixlen 64 scopeid 0x20ether fe:54:00:d1:81:67 txqueuelen 1000 (Ethernet)RX packets 85 bytes 7298 (7.1 KiB)RX errors 0 dropped 0 overruns 0 frame 0TX packets 731 bytes 62680 (61.2 KiB)TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

　　　　查看桥接信息　　

brctl show

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