linux网络基础管理
@
目录
1. 网卡命名
1.1 传统网卡命名机制
传统命名：
以太网eth[0,1,2,...]
wlan[0,1,2,...]
1.2 redhat7网卡命名机制
systemd对网络设备的命名方式：
如果Firmware或BIOS为主板上集成的设备提供的索引信息可用，且可预测，则根据此索引进行命名，例如eno1
如果Firmware或BIOS为PCI-E扩展槽所提供的索引信息可用，且可预测，则根据此索引进行命名，例如ens1
如果硬件接口的物理位置信息可用，则根据此信息进行命名，例如enp2s0
如果用户显式启动，也可根据MAC地址进行命名，例如enx2387a1dc56
上述均不可用时，则使用传统命名机制
上述命名机制中，有的需要biosdevname程序的参与。所以必须安装biosdevname程序且启用它。
1.3 网络接口名称组成格式
基于固件、设备结构、设备类型
由两个字母开头标示固件
以太网网卡以 en 开头
无线网卡以 wl 开头
设备结构
o：主板上集成的设备的设备索引号
s：扩展槽的索引号
x：基于MAC地址的命名
p
1.4 网卡设备的命名过程
udev，辅助工具程序/lib/udev/rename_device会根据/usr/lib/udev/rules.d/60-net.rules中的信息设定网卡名称
biosdevname会根据/usr/lib/udev/rules.d/71-biosdevname.rules中的信息设定网卡名称
通过udev检测网络接口设备，根据/usr/lib/udev/rules.d/75-net-description中的变量信息设定网卡名称
回归传统名
[root@localhost ~]# mv /etc/sysconfig/network-scripts/ifcfg-ens33 /etc/sysconfig/network-scripts/ifcfg-eth0
[root@localhost ~]# ls /etc/sysconfig/network-scripts/ |grep ifcfg-e
ifcfg-eth0
[root@localhost ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0
[root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
UUID=52ed696c-ea51-4509-89b8-cfa4a7f22aee
DEVICE=eth0 //修改
NAME=eth0 //修改
ONBOOT=yes
//编辑/etc/default/grub配置文件，在以GRUB_CMDLINE_LINUX开头的行内rhgb的前面加上net.ifnames=0 biosdevname=0
[root@localhost ~]# vim /etc/default/grub
[root@localhost ~]# cat /etc/default/grub
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap net.ifnames=0 biosdevname=0 rhgb quiet"
|------------添加-----------|
GRUB_DISABLE_RECOVERY="true"
//为grub2生成其配置文件
[root@localhost ~]# grub2-mkconfig -o /etc/grub2.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-693.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-693.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-56592b1fdc854164b8d6f8107bb3caa0
Found initrd image: /boot/initramfs-0-rescue-56592b1fdc854164b8d6f8107bb3caa0.img
done
//重启生效
[root@localhost ~]# reboot
[root@localhost ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:84:06:e4 brd ff:ff:ff:ff:ff:ff
inet 192.168.213.132/24 brd 192.168.213.255 scope global dynamic eth0
valid_lft 1694sec preferred_lft 1694sec
inet6 fe80::f6f:62de:73a6:fa93/64 scope link
valid_lft forever preferred_lft forever
2. 网络管理常用命令
2.1 ifconfig
//查看当前处于活动状态的所有网络接口
[root@localhost ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.213.132 netmask 255.255.255.0 broadcast 192.168.213.255
inet6 fe80::f6f:62de:73a6:fa93 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:84:06:e4 txqueuelen 1000 (Ethernet)
RX packets 1582 bytes 141335 (138.0 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 960 bytes 111137 (108.5 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 68 bytes 5792 (5.6 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 68 bytes 5792 (5.6 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
//仅查看eth0网卡状态
[root@localhost ~]# ifconfig eth0
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.213.132 netmask 255.255.255.0 broadcast 192.168.213.255
inet6 fe80::f6f:62de:73a6:fa93 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:84:06:e4 txqueuelen 1000 (Ethernet)
RX packets 1612 bytes 143825 (140.4 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 978 bytes 113851 (111.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
//查看所有网卡状态信息, 包括禁用和启用
[root@localhost ~]# ifconfig -a
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.213.132 netmask 255.255.255.0 broadcast 192.168.213.255
inet6 fe80::f6f:62de:73a6:fa93 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:84:06:e4 txqueuelen 1000 (Ethernet)
RX packets 1657 bytes 147697 (144.2 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1006 bytes 117125 (114.3 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 68 bytes 5792 (5.6 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 68 bytes 5792 (5.6 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
//关闭 （lo） 接口
[root@localhost ~]# ifconfig lo down
打开网卡（lo）接口
[root@localhost ~]# ifconfig lo up
//网卡配置信息含义如下:
UP: 网卡处于活动状态
BROADCAST: 支持广播
RUNNING: 网线已接入
MULTICAST: 支持组播
MTU: 最大传输单元(字节),即此接口一次所能传输的最大封包
inet: 显示IPv4地址行
inet6: 显示IPv6地址行
link/enther: 指设备硬件(MAC)地址
txqueuelen: 传输缓存区长度大小
RX packets: 接收的数据包
TX packets: 发送的数据包
errors: 总的收包的错误数量
dropped: 由于各种原因, 导致拷贝在内存过程中被丢弃
collisions: 网络信号冲突情况, 值不为0则可能存在网络故障
2.2 ip
//语法：ip [ OPTIONS ] OBJECT { COMMAND | help }
OBJECT：
link：网络接口属性
addr：协议地址
route：路由
//查看IP信息
[root@localhost ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:84:06:e4 brd ff:ff:ff:ff:ff:ff
inet 192.168.213.132/24 brd 192.168.213.255 scope global dynamic eth0
valid_lft 1242sec preferred_lft 1242sec
inet6 fe80::f6f:62de:73a6:fa93/64 scope link
valid_lft forever preferred_lft forever
//查看网络接口所有地址
[root@localhost ~]# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000
link/ether 00:0c:29:84:06:e4 brd ff:ff:ff:ff:ff:f
//显示报文统计信息
[root@localhost ~]# ip -s link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
RX: bytes packets errors dropped overrun mcast
0 0 0 0 0 0
TX: bytes packets errors dropped carrier collsns
0 0 0 0 0 0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT qlen 1000
link/ether 00:0c:29:84:06:e4 brd ff:ff:ff:ff:ff:ff
RX: bytes packets errors dropped overrun mcast
13396 127 0 0 0 0
TX: bytes packets errors dropped carrier collsns
14967 129 0 0 0 0
//启用或禁用网络接口ip link set DEV {up|down}
[root@localhost ~]# ip link set lo down
[root@localhost ~]# ip link set lo up
//ip addr add ADDRESS dev DEV：添加IP地址
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:84:06:e4 brd ff:ff:ff:ff:ff:ff
inet 192.168.213.132/24 brd 192.168.213.255 scope global dynamic eth0
valid_lft 1429sec preferred_lft 1429sec
inet6 fe80::f6f:62de:73a6:fa93/64 scope link
valid_lft forever preferred_lft forever
[root@localhost ~]# ip addr add 192.168.213.130/24 dev eth0
[root@localhost ~]# ip addr show eth0
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:84:06:e4 brd ff:ff:ff:ff:ff:ff
inet 192.168.213.132/24 brd 192.168.213.255 scope global dynamic eth0
valid_lft 1287sec preferred_lft 1287sec
inet 192.168.213.130/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet6 fe80::f6f:62de:73a6:fa93/64 scope link
valid_lft forever preferred_lft forever
//ip addr del ADDRESS dev DEV：删除IP地址
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:84:06:e4 brd ff:ff:ff:ff:ff:ff
inet 192.168.213.132/24 brd 192.168.213.255 scope global dynamic eth0
valid_lft 1287sec preferred_lft 1287sec
inet 192.168.213.130/24 scope global secondary eth0
valid_lft forever preferred_lft forever
inet6 fe80::f6f:62de:73a6:fa93/64 scope link
valid_lft forever preferred_lft forever
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:84:06:e4 brd ff:ff:ff:ff:ff:ff
inet 192.168.213.132/24 brd 192.168.213.255 scope global dynamic eth0
valid_lft 1121sec preferred_lft 1121sec
inet6 fe80::f6f:62de:73a6:fa93/64 scope link
valid_lft forever preferred_lft forever
//ip addr show DEV：查看网络接口的地址
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:84:06:e4 brd ff:ff:ff:ff:ff:ff
inet 192.168.213.132/24 brd 192.168.213.255 scope global dynamic eth0
valid_lft 1041sec preferred_lft 1041sec
inet6 fe80::f6f:62de:73a6:fa93/64 scope link
valid_lft forever preferred_lft forever
//ip route：routing table management 路由管理 //`在这里插入代码片`
//添加路由：ip route add TARGET via GW dev IFACE src SOURCE_IP
TARGET：
主机路由：IP
网络路由：NETWORK/MASK
//删除路由：ip route del TARGET
TARGET：
主机路由：IP
网络路由：NETWORK/MASK
//查看路由：ip route show
//刷新路由表：ip route flush
[dev IFACE]
[via PREFIX]
2.3 route
Linux主机之间是使用IP进行通信, 假设A主机和B主机同在一个网段内且网卡都处于激活状态, 则A具备和B直接通信的能力, 但如果A主机和B主机处于两个不同的网段, 则A必须通过路由器才能和B通信, 路由器属于IT设备的基础设施, 每一个网段都应该至少有一个网关
//查看当前路由表
[root@localhost ~]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default gateway 0.0.0.0 UG 100 0 0 eth0
192.168.213.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
//以数字方式显示各主机或端口等相关信息
[root@localhost ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.213.2 0.0.0.0 UG 100 0 0 eth0
192.168.213.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
//增加路由
//语法：route add [-net|-host] target [netmask Nm] [gw Gw] [[dev] If]
//增加网段路由
[root@localhost ~]# route add -net 192.168.1.0/24 gw 192.168.1.254 dev eth0
[root@localhost ~]# route add -net 0.0.0.0/0 gw 192.168.1.254 dev eth0
//增加主机路由
[root@localhost ~]# route add -host 172.16.12.128 gw 172.16.12.2
//例：
[root@guilai ~]# route add -net 192.168.161.0/24 gw 192.168.213.2 dev eth0
[root@guilai ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.213.2 0.0.0.0 UG 100 0 0 eth0
192.168.161.0 192.168.213.2 255.255.255.0 UG 0 0 0 eth0
192.168.213.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
[root@guilai ~]# route del -net 192.168.161.0/24
[root@guilai ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.213.2 0.0.0.0 UG 100 0 0 eth0
192.168.213.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
//删除路由
[root@localhost ~]# route del -net 192.168.1.0/24
[root@localhost ~]# route del -net 0.0.0.0 gw 192.168.1.254
2.4 hostname与hostnamectl
生产环境中必须配置主机名,同时主机名也需要遵循一定的规范, 比如:
公有云: 地区-项目-业务-服务-节点-地址
wh-shop-register-nginx-node1-192.168.56.13
wh-med-pay-mysql-master01-192.168.56.11
wh-med-pay-mysql-slave01-192.168.56.12
//hostname查看主机名
[root@localhost ~]# hostname
localhost.localdomain
//hostname临时修改主机名
[root@localhost ~]# hostname tianxiadiyi
[root@localhost ~]# cat /etc/hostname
localhost.localdomain
//注意：修改主机名后需要重新登录用户才会显示效果
//rhel7系统建议使用hostnamectl修改和查看主机名
//设定永久名称
[root@localhost ~]# hostnamectl set-hostname guilai
[root@localhost ~]# cat /etc/hostname
guilai
//查看主机信息
[root@localhost ~]# hostnamectl
Static hostname: guilai
Icon name: computer-vm
Chassis: vm
Machine ID: 56592b1fdc854164b8d6f8107bb3caa0
Boot ID: 9d806f2ea7c54acbb7f100c0bcce2a18
Virtualization: vmware
Operating System: Red Hat Enterprise Linux Server 7.4 (Maipo)
CPE OS Name: cpe:/o:redhat:enterprise_linux:7.4:GA:server
Kernel: Linux 3.10.0-693.el7.x86_64
Architecture: x86-64
注意：
在Linux中以命令方式修改网络配置只在当前状态有效，重启后将失效。故若想使修改的配置重启后依然有效，则必须编辑配置文件进行配置的修改。
3.网络相关配置文件
//网络配置文件：/etc/sysconfig/network
NETWORKING={yes|no}：设定整个系统是否启用网络功能，若设为no，则不论网卡如何设置都不能使用网络功能。
HOSTNAME：设置主机名
3.2 网络接口配置文件
网络接口即网卡，其配置文件的路径是/etc/sysconfig/network-scripts/ifcfg-INTERFACE_NAME
[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0
TYPE=Ethernet //接口类型。常见的接口类型有：Ethernet，Bridge
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static //引导协议，可选值有｛static｜none｜dhcp｜bootp｝。如果要使用静态地址，使用static或none都可以
DEFROUTE=yes //将接口设定为默认路由[yes|no]
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
UUID=52ed696c-ea51-4509-89b8-cfa4a7f22aee //设备的惟一标识
DEVICE=eth0 //关联的设备名称，要与文件名的后半部"INTERFACE_NAME"保持一致
NAME=eth0 //连接名称
ONBOOT=yes //在系统引导时是否自动激活此网络接口，可选值有{ yes ｜ no }
IPADDR=192.168.213.132 //固定IP地址
NETMASK=255.255.255.0 //子网掩码//子网掩码 PREFIX=24也是子网掩码
GATEWAY=192.168.213.2 //默认网关
DNS1=192.168.213.2 //第一个DNS服务器指向， DNS2 //第二个DNS服务器指向
//网卡配置说明
//参数 说明
BOOTPROTO=none //引导协议，可选值有｛static｜none｜dhcp｜bootp｝。如果要使用静态地址，使用static或none都可以
NM_CONTROLLED //NM是NetworkManager的简写，NM是由RHEL研发的在RHEL6中取代network脚本来实现网络管理、配置的服务脚本
//可选值有{ yes ｜ no }
//此项是设定此网卡是否接受NM控制。CentOS6建议设为“no”
TYPE //接口类型。常见的接口类型有：Ethernet，Bridge
UUID //设备的惟一标识
HWADDR //硬件地址，要与硬件中的地址保持一致，可省
IPADDR=172.16.12.130 //固定IP地址
PREFIX=24 //子网掩码
NETMASK=255.255.255.0 //子网掩码
GATEWAY=172.16.12.2 //默认网关
DNS1=172.16.12.2 //第一个DNS服务器指向
DNS2 //第二个DNS服务器指向
DNS3 //第三个DNS服务器指向
DEVICE=eth1 //关联的设备名称，要与文件名的后半部"INTERFACE_NAME"保持一致
NAME="eth1" //连接名称
ONBOOT=yes //在系统引导时是否自动激活此网络接口，可选值有{ yes ｜ no }
DEFROUTE=yes //将接口设定为默认路由[yes|no]
USERCTL={yes|no} //是否允许普通用户控制此接口的启用与禁用
PEERDNS={yes|no} //是否在BOOTPROTO为dhcp时接受由dhcp服务器指定的DNS地址，此项设为yes时获得的DNS地址将直接覆盖至/etc/resolv.conf文件中
3.3路由配置文件
路由配置文件的路径是/etc/sysconfig/network-scripts/route-INTERFACE_NAME
//添加格式一：DEST via NEXTHOP
[root@localhost ~]# vi /etc/sysconfig/network-scripts/route-ens33 //用vi生成编辑
172.16.12.0/24 via 172.16.12.2
//添加格式二：
[root@localhost ~]# vi /etc/sysconfig/network-scripts/route-ens33
ADDRESS0=172.16.12.0
NETMASK0=255.255.255.0
GATEWAY0=172.16.12.2
3.4DNS配置文件
DNS配置文件的路径是/etc/resolv.conf
[root@localhost ~]# vi /etc/resolv.conf
nameserver DNS_IP_1
nameserver DNS_IP_2
nameserver DNS_IP_3
没必要配置这个，如果在vi /etc/sysconfig/network-scripts/ifcfg-eth0
4. NetworkManager管理网络
RHEL/CentOS7系统默认使用NetworkManager来提供网络服务，这是一种动态管理网络配置的守护进程，能够让网络设备保持连接状态。
NetworkManager提供的命令行和图形配置工具对网络进行设定, 设定保存的配置文件在/etc/sysconfig/network-scripts目录下, 工具有 nmcli, nmtui, nm-connect-editor
device物理设备, 例如 ens33,enp2s0,virbr0,team0
connection连接设置, 具体网络配置方案
1.不同的网络连接配置可以应用到相同的物理设备，但物理设备同一时间只能应用其中某个网络连接
2.针对物理网络接口, 设定不同的网络连接, 在不同的使用环境中激活相应的网络连接，就可以实现网络配置信息的自动切换了
使用nmcli命令查看设备以及连接情况
//查看设备状态
[root@guilai ~]# nmcli device
设备 类型 状态 连接
eth0 ethernet 连接的 eth0
lo loopback 未托管 --
//查看指定设备的详细状态
[root@guilai ~]# nmcli device show eth0
GENERAL.设备: eth0
GENERAL.类型: ethernet
GENERAL.硬盘: 00:0C:29:84:06:E4
GENERAL.MTU: 1500
GENERAL.状态: 100 (连接的)
GENERAL.连接: eth0
GENERAL.连接路径: /org/freedesktop/NetworkManager/ActiveConnection/2
WIRED-PROPERTIES.载波: 开
IP4.地址[1]: 192.168.213.132/24
IP4.网关: 192.168.213.2
IP4.DNS[1]: 192.168.213.2
IP6.地址[1]: fe80::f6f:62de:73a6:fa93/64
IP6.网关: --
//查看连接状态 //查看所有活动的连接
[root@guilai ~]# nmcli connection
名称 UUID 类型 设备
eth0 52ed696c-ea51-4509-89b8-cfa4a7f22aee 802-3-ethernet eth0
//查看指定设备连接的详细情况
[root@guilai ~]# nmcli connection show eth0
connection.id: eth0
connection.uuid: 52ed696c-ea51-4509-89b8-cfa4a7f22aee
connection.stable-id: --
connection.interface-name: eth0
connection.type: 802-3-ethernet
connection.autoconnect: yes
connection.autoconnect-priority: 0
connection.autoconnect-retries: -1 (默认)
connection.timestamp: 1570532473
connection.read-only: no
connection.permissions: --
connection.zone: --
.....................
5. 使用原生network管理网络
CentOS/RHEL的网络配置文件默认目录为/etc/sysconfig/network-scripts
默认第一块物理网卡配置文件为ifcfg-eth0, 如果有第二块物理网卡, 配置文件则为ifcfg-eth1以此类推。 注意: 如果新增物理网卡没有配置文件，可选择复制系统默认的进行修改。
//设置NetworkManger开机不启动, 同时停止NetworkManger服务
[root@localhost ~]# systemctl disable NetworkManager
[root@localhost ~]# systemctl stop NetworkManager
//添加一块物理网卡, 然后新增网络连接配置文件
//复制配置eth0配置文件为eth1
/添加一块物理网卡, 然后新增网络连接配置文件
//复制配置eth0配置文件为eth1
[root@localhost ~]# cp /etc/sysconfig/network-scripts/{ifcfg-eth0,ifcfg-eth1}
//编辑网卡配置文件
[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth1
TYPE=Ethernet
BOOTPROTO=static
NAME=eth1
UUID=03be31f5-a3c1-4f8d-88b3-aea6e85c869f
DEVICE=eth1
NM_CONTROLLED=no
ONBOOT=yes
IPADDR=172.16.12.130
NETMASK=255.255.255.0
GATEWAY=172.16.12.2
DNS1=172.16.12.2
//重启network网络服务加载网络并设置开机启动
[root@localhost ~]# systemctl restart network
[root@localhost ~]# systemctl enable network
6.网络检测工具与故障排查
6.1 ping
ping命令的目的在于测试另一台主机是否可达, 如果ping不到某台主机,就说明对方主机已经出现了问题, 但是不排除由于链路中的防火墙、ping被丢弃等原因造成ping不通的情况
//ping命令常用选项：
-c 指定ping的次数
-i 指定ping包的发送间隔
-w 如果ping没有回应, 则在指定超时时间后退出
// ping 5 次
[root@guilai ~]# ping -c 5 www.baidu.com
PING www.a.shifen.com (182.61.200.6) 56(84) bytes of data.
64 bytes from 182.61.200.6 (182.61.200.6): icmp_seq=1 ttl=128 time=21.8 ms
64 bytes from 182.61.200.6 (182.61.200.6): icmp_seq=2 ttl=128 time=27.6 ms
64 bytes from 182.61.200.6 (182.61.200.6): icmp_seq=3 ttl=128 time=47.5 ms
64 bytes from 182.61.200.6 (182.61.200.6): icmp_seq=4 ttl=128 time=22.4 ms
64 bytes from 182.61.200.6 (182.61.200.6): icmp_seq=5 ttl=128 time=21.9 ms
--- www.a.shifen.com ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4008ms
rtt min/avg/max/mdev = 21.837/28.289/47.585/9.893 ms
//每0.1秒ping一次
[root@guilai ~]# ping -i 0.1 www.baidu.com
6.2 host与nslookup
host/nslookup命令用于查询DNS记录
host/nslookup命令用于查询DNS记录
[root@guilai ~]# host www.baidu.com
www.baidu.com is an alias for www.a.shifen.com.
www.a.shifen.com has address 182.61.200.7
www.a.shifen.com has address 182.61.200.6```
[root@guilai ~]# nslookup www.baidu.com
Server: 192.168.213.2
Address: 192.168.213.2#53
Non-authoritative answer:
www.baidu.com canonical name = www.a.shifen.com.
Name: www.a.shifen.com
Address: 182.61.200.6
Name: www.a.shifen.com
Address: 182.61.200.7
yum provides *bin/nslookup 来查看该命令需要安装什么包
6.3 traceroute
traceroute命令用于路由跟踪, 检测网络故障出现在ISP运营商或是对端服务无法响应
[root@guilai ~]# traceroute www.baidu.com
traceroute to www.baidu.com (182.61.200.7), 30 hops max, 60 byte packets
1 gateway (192.168.213.2) 0.097 ms 0.066 ms 0.088 ms
2 * * *
3 * * *
4 * * *
5 * * *
6 * * *
7 * * *
8 * * *
9 * * *
6.4 netstat
netstat用于查看网络状态
//显示路由表
[root@seancheng ~]# netstat -r
[root@guilai ~]# netstat -r
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
default gateway 0.0.0.0 UG 0 0 0 eth0
192.168.213.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
//以数字方式显示路由表
[root@seancheng ~]# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
0.0.0.0 192.168.213.2 0.0.0.0 UG 0 0 0 eth0
192.168.213.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
//显示建立的tcp连接
[root@seancheng ~]# netstat -t
[root@guilai ~]# netstat -t
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 52 guilai:ssh 192.168.213.1:51255 ESTABLISHED
//显示udp连接
[root@seancheng ~]# netstat -u
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
//显示监听状态的连接
[root@seancheng ~]# netstat -l
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN
tcp 0 0 localhost:smtp 0.0.0.0:* LISTEN
tcp6 0 0 [::]:ssh [::]:* LISTEN
tcp6 0 0 localhost:smtp [::]:* LISTEN
udp 0 0 localhost:323 0.0.0.0:*
udp6 0 0 localhost:323 [::]:*
raw6 0 0 [::]:ipv6-icmp [::]:* 7
Active UNIX domain sockets (only servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 19870 private/trace
unix 2 [ ACC ] STREAM LISTENING 19873 private/verify
unix 2 [ ACC ] STREAM LISTENING 19879 private/proxymap
unix 2 [ ACC ] SEQPACKET LISTENING 14350 /run/udev/control
unix 2 [ ACC ] STREAM LISTENING 19882 private/proxywrite
......
//显示监听指定的套接字的进程的进程号及进程名
[root@seancheng ~]# netstat -p
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 52 guilai:ssh 192.168.213.1:51255 ESTABLISHED 1409/sshd: root@pts
Active UNIX domain sockets (w/o servers)
Proto RefCnt Flags Type State I-Node PID/Program name Path
unix 2 [ ] DGRAM 14373 1/systemd /run/systemd/shutdownd
unix 2 [ ] DGRAM 15922 767/chronyd /var/run/chrony/chronyd.sock
unix 2 [ ] DGRAM 9170 1/systemd /run/systemd/notify
unix 2 [ ] DGRAM 9172 1/systemd /run/systemd/cgroups-agent
unix 5 [ ] DGRAM 9183 1/systemd /run/systemd/journal/socket
unix 16 [ ] DGRAM 9185 1/systemd /dev/log
unix 3 [ ] DGRAM 14889 594/systemd-udevd
unix 3 [ ] STREAM CONNECTED 16123 781/crond
unix 3 [ ] STREAM CONNECTED 19848 1342/master
.........
/显示所有状态的连接
[root@seancheng ~]# netstat -a
[root@guilai ~]# netstat -a
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:ssh 0.0.0.0:* LISTEN
tcp 0 0 localhost:smtp 0.0.0.0:* LISTEN
tcp 0 52 guilai:ssh 192.168.213.1:51255 ESTABLISHED
tcp6 0 0 [::]:ssh [::]:* LISTEN
tcp6 0 0 localhost:smtp [::]:* LISTEN
udp 0 0 guilai:48786 makaki.miuku.net:ntp ESTABLISHED
udp 0 0 localhost:323 0.0.0.0:*
udp6 0 0 localhost:323 [::]:*
raw6 0 0 [::]:ipv6-icmp [::]:* 7
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] STREAM LISTENING 19870 private/trace
unix 2 [ ACC ] STREAM LISTENING 19873 private/verify
unix 2 [ ACC ] STREAM LISTENING 19879 private/proxymap
unix 2 [ ACC ] SEQPACKET LISTENING 14350 /run/udev/control
unix 2 [ ACC ] STREAM LISTENING 19882 private/proxywrite
unix 2 [ ACC ] STREAM LISTENING 19885 private/smtp
unix 2 [ ACC ] STREAM LISTENING 19888 private/relay
unix 2 [ ACC ] STREAM LISTENING 19894 private/error
unix 2 [ ] DGRAM 14373 /run/systemd/shutdownd
..................
//常用选项
-antlp
[root@seancheng ~]# netstat -antlp
[root@guilai ~]# netstat -antlp
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1115/sshd
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1342/master
tcp 0 52 192.168.213.132:22 192.168.213.1:51255 ESTABLISHED 1409/sshd: root@pts
tcp6 0 0 :::22 :::* LISTEN 1115/sshd
tcp6 0 0 ::1:25 :::* LISTEN 1342/master
6.5 ss
ss是一种网络状态查看工具，取代netstat
//语法：ss [options] [ FILTER ]
//常用的options：
-t：tcp协议相关
-u：udp协议相关
-w：裸套接字相关
-x：unix套接字相关
-l：listen状态的连接
-a：所有
-n：数字格式
-p：相关的程序及pid
-e：扩展的信息
-m：内存用量
-o：显示计时器信息
//常见的FILTER：
FILTER := [ state TCP-STATE ] [ EXPRESSION ]
如：ss -tan state ESTABLISHED
//常见的state：
//tcp finite state machine：有限状态机
LISTEN：监听
ESTABLISHED：已建立的连接
//EXPRESSION：
dport =
sport =
示例：'( dport = :ssh or sport = :ssh)'，此处的ssh也即服务名可以使用其对应的端口号代替，等号两边必须有空格
//常用组合：
[root@seancheng ~]# ss -tan
[root@guilai ~]# ss -tan
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
ESTAB 0 0 192.168.213.132:22 192.168.213.1:51255
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
[root@seancheng ~]# ss -tanl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
[root@seancheng ~]# ss -antlp
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:* users:(("sshd",pid=1115,fd=3))
LISTEN 0 100 127.0.0.1:25 *:* users:(("master",pid=1342,fd=13))
LISTEN 0 128 :::22 :::* users:(("sshd",pid=1115,fd=4))
LISTEN 0 100 ::1:25 :::* users:(("master",pid=1342,fd=14))
[root@seancheng ~]# ss -anu
State Recv-Q Send-Q Local Address:Port Peer Address:Port
UNCONN 0 0 127.0.0.1:323 *:*
UNCONN 0 0 ::1:323 :::*
常见端口
| 服务 | 端口号 |
|---|---|
| http | 80/tcp |
| https | 443/tcp |
| ssh | 22/tcp |
| ftp | 20,21/tcp |
| mysql | 3306/tcp |
| rsync | 873/rsync |
| redis | 6379/tcp |
| Telnet | 23/tcp |
| TFTP | 69/udp |
6.6 网络故障排查
网络故障分为硬件/软件故障
网卡损坏
链路故障
网卡驱动不兼容
网络排查思路
ping本地回环口, 确定本机TCP/IP协议栈是否正常
ping本机IP地址, 确定本地设备以及驱动是否正常
ping同网段主机, 确定二层网络是否正常工作
ping网关地址, 确定本地与网络是否正常
ping公网地址, 确定本地路由是否正常
ping公网域名, 确定DNS客户端是否正常
服务故障排查思路
使用telnet检测端口是否开放
检查服务端防火墙以及SElinux
检查相应的权限是否配置正常
检查日志是否有异常
检查完毕后持续测试
建议:
所有的排查思路都从OSI七层模型由下往上逐一进行排查(学会看日志)