Linux-网络基础管理
网卡命名
传统网卡命名机制
-
传统命名：
-
以太网eth[0,1,2,...]
-
wlan[0,1,2,...]
-
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
-
ps：基于物理位置拓扑的命名。如enp2s1，表示PCI总线上第2个总线的第1个插槽的设备索引号
-
回归传统命名
问：如何把网卡名称改成eth0?
//第一步：修改网卡配置文件
[root@localhost ~]# cd /etc/sysconfig/network-scripts/
[root@localhost network-scripts]# ls
ifcfg-ens160
[root@localhost network-scripts]# mv ifcfg-ens160 ifcfg-eth0
[root@localhost network-scripts]# vi ifcfg-eth0
TYPE=Ethernet
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
NAME=eth0 //此处要把ens160改成eth0
UUID=d4d7570b-d09c-49d3-a15e-263573ad5d36
DEVICE=eth0 //此处要把ens160改成eth0
ONBOOT=yes
//第二步：编辑/etc/default/grub配置文件,在GRUB_CMDLINE_LINUX那行内rhgb前加net.ifnames=0 biosdevname=0
[root@localhost ~]# vi /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 resume=/dev/mapper/rhel-swap rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap net.ifnames=0 biosdevname=0 rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
GRUB_ENABLE_BLSCFG=true
//第三步：为grub2生成其配置文件
[root@localhost ~]# grub2-mkconfig -o /etc/grub2.cfg
Generating grub configuration file ...
done
//第四步：重启系统
[root@localhost ~]# reboot
网络管理常用命令
ifconfig（需要安装net-tools）
[root@localhost ~]# ifconfig
-bash: ifconfig: command not found
[root@localhost ~]# mount /dev/cdrom /mnt/
mount: /mnt: WARNING: device write-protected, mounted read-only.
[root@localhost ~]# rpm -ivh /mnt/BaseOS/Packages/net-tools-2.0-0.51.20160912git.el8.x86_64.rpm
warning: /mnt/BaseOS/Packages/net-tools-2.0-0.51.20160912git.el8.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID fd431d51: NOKEY
Verifying... ################################# [100%]
Preparing... ################################# [100%]
Updating / installing...
1:net-tools-2.0-0.51.20160912git.el################################# [100%]
//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 192.168.237.128 netmask 255.255.255.0 broadcast 192.168.237.255
inet6 fe80::6132:2a03:6fc1:9bed prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:f9:ec:35 txqueuelen 1000 (Ethernet)
RX packets 400 bytes 34410 (33.6 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 257 bytes 34769 (33.9 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 1000 (Local Loopback)
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
//仅查看eth0网卡状态
[root@localhost ~]# ifconfig eth0
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.237.128 netmask 255.255.255.0 broadcast 192.168.237.255
inet6 fe80::6132:2a03:6fc1:9bed prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:f9:ec:35 txqueuelen 1000 (Ethernet)
RX packets 438 bytes 37382 (36.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 280 bytes 37615 (36.7 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 192.168.237.128 netmask 255.255.255.0 broadcast 192.168.237.255
inet6 fe80::6132:2a03:6fc1:9bed prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:f9:ec:35 txqueuelen 1000 (Ethernet)
RX packets 460 bytes 39120 (38.2 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 294 bytes 39379 (38.4 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 1000 (Local Loopback)
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
网卡配置信息含义:
| 列名 | 含义 |
|---|---|
| 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 |
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 group default qlen 1000
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 fq_codel state UP mode DEFAULT group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
//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 group default qlen 1000
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 fq_codel state UP mode DEFAULT group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
RX: bytes packets errors dropped overrun mcast
49544 603 0 0 0 0
TX: bytes packets errors dropped carrier collsns
44711 348 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 up
[root@localhost ~]# ip link set lo down
//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 fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.237.128/24 brd 192.168.237.255 scope global dynamic noprefixroute eth0
valid_lft 1621sec preferred_lft 1621sec
inet6 fe80::6132:2a03:6fc1:9bed/64 scope link noprefixroute
//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 fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.237.128/24 brd 192.168.237.255 scope global dynamic noprefixroute eth0
valid_lft 1708sec preferred_lft 1708sec
inet6 fe80::6132:2a03:6fc1:9bed/64 scope link noprefixroute
valid_lft forever preferred_lft forever
[root@localhost ~]# ip addr add 192.168.1.1/24 dev eth0
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.237.128/24 brd 192.168.237.255 scope global dynamic noprefixroute eth0
valid_lft 1674sec preferred_lft 1674sec
inet 192.168.1.1/24 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::6132:2a03:6fc1:9bed/64 scope link noprefixroute
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 fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.237.128/24 brd 192.168.237.255 scope global dynamic noprefixroute eth0
valid_lft 1638sec preferred_lft 1638sec
inet 192.168.1.1/24 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::6132:2a03:6fc1:9bed/64 scope link noprefixroute
valid_lft forever preferred_lft forever
[root@localhost ~]# ip addr del 192.168.1.1/24 dev eth0
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.237.128/24 brd 192.168.237.255 scope global dynamic noprefixroute eth0
valid_lft 1621sec preferred_lft 1621sec
inet6 fe80::6132:2a03:6fc1:9bed/64 scope link noprefixroute
valid_lft forever preferred_lft forever
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
192.168.237.0 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
0.0.0.0 192.168.237.2 0.0.0.0 UG 100 0 0 eth0
192.168.237.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
//添加主机路由
[root@localhost ~]# ip addr add 192.168.1.1/24 dev eth0
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.237.128/24 brd 192.168.237.255 scope global dynamic noprefixroute eth0
valid_lft 954sec preferred_lft 954sec
inet 192.168.1.1/24 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::6132:2a03:6fc1:9bed/64 scope link noprefixroute
valid_lft forever preferred_lft forever
[root@localhost ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.237.2 0.0.0.0 UG 100 0 0 eth0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.237.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
[root@localhost ~]# route add -host 192.168.1.1 gw 192.168.1.254
[root@localhost ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.237.2 0.0.0.0 UG 100 0 0 eth0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.1.1 192.168.1.254 255.255.255.255 UGH 0 0 0 eth0
192.168.237.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
//删除路由
[root@localhost ~]# route del 192.168.1.1
[root@localhost ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.237.2 0.0.0.0 UG 100 0 0 eth0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.237.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
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
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 yuqinghao
[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 yuqinghao
[root@localhost ~]# cat /etc/hostname
yuqinghao
//查看主机信息
[root@localhost ~]# hostnamectl
Static hostname: yuqinghao
Icon name: computer-vm
Chassis: vm
Machine ID: 298d293aae1e4da99fe4573bb610ebb0
Boot ID: cc0222a1fbd843a3a4bc71b9e7f82e1a
Virtualization: vmware
Operating System: Red Hat Enterprise Linux 8.2 (Ootpa)
CPE OS Name: cpe:/o:redhat:enterprise_linux:8.2:GA
Kernel: Linux 4.18.0-193.el8.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。
网络相关配置文件
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-网卡名字
[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0
TYPE=Ethernet
BOOTPROTO=static
NAME=eth0
UUID=03be31f5-a3c1-4f8d-88b3-aea6e85c869f
DEVICE=eth0
ONBOOT=yes
IPADDR=192.168.237.128
NETMASK=255.255.255.0
GATEWAY=192.168.237.2
DNS1=114.114.114.114
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，可以省略 |
| IPADDR=192.168.237.128 | 固定IP地址 |
| PREFIX=24 | 子网掩码 |
| NETMASK=255.255.255.0 | 子网掩码 |
| GATEWAY=192.168.237.254 | 默认网关 |
| DNS1=114.114.114.114 | 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=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 } |
| 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 |
小扩展：如何添加多个IP地址、DNS、网关，并且重启后还存在呢？
[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0
TYPE=Ethernet
BOOTPROTO=static
NAME=eth0
UUID=03be31f5-a3c1-4f8d-88b3-aea6e85c869f
DEVICE=eth0
ONBOOT=yes
IPADDR0=192.168.237.128
NETMASK0=255.255.255.0
GATEWAY=192.168.237.2
DNS1=114.114.114.114
DNS2=8.8.8.8
IPADDR1=192.168.237.129
NETMASK1=255.255.255.0
[root@localhost ~]# systemctl restart NetworkManager
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.237.128/24 brd 192.168.237.255 scope global dynamic noprefixroute eth0
valid_lft 1777sec preferred_lft 1777sec
inet 192.168.1.1/24 scope global eth0
valid_lft forever preferred_lft forever
inet6 fe80::6132:2a03:6fc1:9bed/64 scope link noprefixroute
valid_lft forever preferred_lft forever
//此时重启网卡后没有刷新出来需要禁用再启用网卡
[root@localhost ~]# ifdown eth0;ifup eth0
Connection 'eth0' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/2)
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/4)
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.237.128/24 brd 192.168.237.255 scope global noprefixroute eth0
valid_lft forever preferred_lft forever
inet 192.168.237.129/24 brd 192.168.237.255 scope global secondary noprefixroute eth0
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fef9:ec35/64 scope link
valid_lft forever preferred_lft forever
[root@localhost ~]# reboot
[root@localhost ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.237.128/24 brd 192.168.237.255 scope global noprefixroute eth0
valid_lft forever preferred_lft forever
inet 192.168.237.129/24 brd 192.168.237.255 scope global secondary noprefixroute eth0
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fef9:ec35/64 scope link
valid_lft forever preferred_lft forever
小扩展：如何在新添加一块网卡，并且修改它的IP地址为192.168.10.1？
//第一步：关机新添加网络适配器
[root@localhost ~]# shutdown -h now
//开机后，发现新加了一个eth1
[root@localhost ~]# ip addr
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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:35 brd ff:ff:ff:ff:ff:ff
inet 192.168.237.128/24 brd 192.168.237.255 scope global noprefixroute eth0
valid_lft forever preferred_lft forever
inet 192.168.237.129/24 brd 192.168.237.255 scope global secondary noprefixroute eth0
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fef9:ec35/64 scope link
valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:3f brd ff:ff:ff:ff:ff:ff
inet 192.168.237.130/24 brd 192.168.237.255 scope global dynamic noprefixroute eth1
valid_lft 1601sec preferred_lft 1601sec
inet6 fe80::c8bc:9bc7:cedd:aa2a/64 scope link noprefixroute
valid_lft forever preferred_lft forever
//准备修改IP地址的时候却发现没有配置文件
[root@localhost ~]# ls /etc/sysconfig/network-scripts/
ifcfg-eth0
//第二步：创建配置文件
[root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth1
TYPE=Ethernet
BOOTPROTO=static
NAME=eth1
DEVICE=eth1
ONBOOT=yes
IPADDR=192.168.10.1
PREFIX=24
//第三步：重启网卡
[root@localhost ~]# systemctl restart NetworkManager
[root@localhost ~]# ifdown eth1;ifup eth1
Connection 'eth1' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/3)
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/5)
//成功
[root@localhost ~]# ip addr show eth1
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:f9:ec:3f brd ff:ff:ff:ff:ff:ff
inet 192.168.10.1/24 brd 192.168.10.255 scope global noprefixroute eth1
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fef9:ec3f/64 scope link
valid_lft forever preferred_lft forever
DNS配置文件
DNS配置文件的路径是/etc/resolv.conf
[root@localhost ~]# cat /etc/resolv.conf
# Generated by NetworkManager
search localdomain
nameserver 192.168.237.2
nameserver 114.114.114.114
nameserver 8.8.8.8
注意：网卡配置文件的DNS会覆盖它，尽量不要直接在这个文件里修改DNS
路由配置文件
路由配置文件的路径是/etc/sysconfig/network-scripts/route-网卡名字
//添加路由
[root@localhost ~]# cd /etc/sysconfig/network-scripts/
[root@localhost network-scripts]# ls
ifcfg-eth0 ifcfg-eth1
//添加格式一：
[root@localhost network-scripts]# vi route-eth1
192.168.10.0/24 via 192.168.10.254
192.168.20.0/24 via 192.168.20.254
//添加格式二：
[root@localhost network-scripts]# vi route-eth1
ADDRESS0=192.168.10.0
NETMASK0=255.255.255.0
GATEWAY0=192.168.10.2
ADDRESS0=192.168.20.0
NETMASK0=255.255.255.0
GATEWAY0=192.168.20.2
[root@localhost network-scripts]# systemctl restart NetworkManager
[root@localhost network-scripts]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.10.0 0.0.0.0 255.255.255.0 U 101 0 0 eth1
192.168.237.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
192.168.237.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
[root@localhost network-scripts]# ifdown eth1;ifup eth1
Connection 'eth1' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/2)
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/4)
[root@localhost network-scripts]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.10.0 0.0.0.0 255.255.255.0 U 101 0 0 eth1
192.168.20.0 192.168.20.254 255.255.255.0 UG 101 0 0 eth1
192.168.20.254 0.0.0.0 255.255.255.255 UH 101 0 0 eth1
192.168.237.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
192.168.237.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
//删除路由
[root@localhost network-scripts]# rm -f route-eth1
[root@localhost network-scripts]# ifdown eth1;ifup eth1
Connection 'eth1' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/4)
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/6)
[root@localhost network-scripts]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.10.0 0.0.0.0 255.255.255.0 U 101 0 0 eth1
192.168.237.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
192.168.237.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
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-connection-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
- 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
- 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@localhost ~]# nmcli device
DEVICE TYPE STATE CONNECTION
eth0 ethernet connected eth0
eth1 ethernet connected eth1
lo loopback unmanaged --
//查看指定设备的详细状态
[root@localhost ~]# nmcli device show eth0
GENERAL.DEVICE: eth0
GENERAL.TYPE: ethernet
GENERAL.HWADDR: 00:0C:29:F9:EC:35
GENERAL.MTU: 1500
GENERAL.STATE: 100 (connected)
GENERAL.CONNECTION: eth0
GENERAL.CON-PATH: /org/freedesktop/NetworkManager/ActiveConnection/1
WIRED-PROPERTIES.CARRIER: on
IP4.ADDRESS[1]: 192.168.237.128/24
IP4.ADDRESS[2]: 192.168.237.129/24
IP4.GATEWAY: --
IP4.ROUTE[1]: dst = 192.168.237.0/24, nh = 0.0.0.0, mt = 100
IP4.ROUTE[2]: dst = 192.168.237.0/24, nh = 0.0.0.0, mt = 100
IP4.DNS[1]: 114.114.114.114
IP4.DNS[2]: 8.8.8.8
IP6.ADDRESS[1]: fe80::20c:29ff:fef9:ec35/64
IP6.GATEWAY: --
IP6.ROUTE[1]: dst = fe80::/64, nh = ::, mt = 256
IP6.ROUTE[2]: dst = ff00::/8, nh = ::, mt = 256, table=255
//查看连接状态
[root@localhost ~]# nmcli connection
NAME UUID TYPE DEVICE
eth0 03be31f5-a3c1-4f8d-88b3-aea6e85c869f ethernet eth0
eth1 9c92fad9-6ecb-3e6c-eb4d-8a47c6f50c04 ethernet eth1
Wired connection 1 7da8e5ae-c71c-3b8f-b8e2-3cee25b95067 ethernet --
//查看所有活动的连接
[root@localhost ~]# nmcli connection show eth0
connection.id: eth0
connection.uuid: 03be31f5-a3c1-4f8d-88b3-aea6e85c869f
connection.stable-id: --
connection.type: 802-3-ethernet
connection.interface-name: eth0
connection.autoconnect: yes
connection.autoconnect-priority: 0
connection.autoconnect-retries: -1 (default)
connection.multi-connect: 0 (default)
connection.auth-retries: -1
connection.timestamp: 1606555164
connection.read-only: no
connection.permissions: --
connection.zone: --
connection.master: --
connection.slave-type: --
connection.autoconnect-slaves: -1 (default)
connection.secondaries: --
connection.gateway-ping-timeout: 0
connection.metered: unknown
connection.lldp: default
connection.mdns: -1 (default)
connection.llmnr: -1 (default)
connection.wait-device-timeout: -1
802-3-ethernet.port: --
802-3-ethernet.speed: 0
802-3-ethernet.duplex: --
802-3-ethernet.auto-negotiate: no
802-3-ethernet.mac-address: --
802-3-ethernet.cloned-mac-address: --
802-3-ethernet.generate-mac-address-mask:--
802-3-ethernet.mac-address-blacklist: --
802-3-ethernet.mtu: auto
802-3-ethernet.s390-subchannels: --
802-3-ethernet.s390-nettype: --
802-3-ethernet.s390-options: --
802-3-ethernet.wake-on-lan: default
802-3-ethernet.wake-on-lan-password: --
ipv4.method: manual
ipv4.dns: 114.114.114.114,8.8.8.8
ipv4.dns-search: --
ipv4.dns-options: --
ipv4.dns-priority: 0
ipv4.addresses: 192.168.237.128/24, 192.168.237.129/24
ipv4.gateway: --
ipv4.routes: --
nmtui //字符界面图形模式配置
//第一步:输入命令nmtui
[root@localhost ~]# nmtui
进入配置界面,选择Edit a connection
Edit a connection:设置一个连接,可以添加删除网络配置
Activate a connection:激活一个连接,可以启用禁用网络配置
Set system hostname:设置hostname
//第二步:选择网络接口
//第三步:进行网络配置
//第四步:OK保存 最后Quit退出 重启网卡就成功了
网络检测工具与故障排查
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
[root@localhost ~]# ping www.baidu.com
PING www.a.shifen.com (182.61.200.7) 56(84) bytes of data.
64 bytes from localhost (182.61.200.7): icmp_seq=1 ttl=128 time=22.1 ms
64 bytes from localhost (182.61.200.7): icmp_seq=2 ttl=128 time=22.7 ms
64 bytes from localhost (182.61.200.7): icmp_seq=3 ttl=128 time=22.2 ms
^C
--- www.a.shifen.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 7ms
rtt min/avg/max/mdev = 22.143/22.321/22.651/0.263 ms
host与nslookup
host/nslookup命令用于查询DNS记录(需要安装bind-utils)
安装步骤:
//配置yum源
[root@localhost ~]# mount /dev/cdrom /mnt/
[root@localhost ~]# vi /etc/yum.repos.d/xx.repo
[BaseOS]
name=BaseOS
baseurl=file:///mnt/BaseOS
gpgpcheck=0
enabled=1
[AppStream]
name=AppStream
baseurl=file:///mnt/AppStream
gpgpcheck=0
enabled=1
[root@localhost ~]# yum clean all
Updating Subscription Management repositories.
Unable to read consumer identity
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
0 files removed
[root@localhost yum.repos.d]# yum -y install bind-utils
Updating Subscription Management repositories.
Unable to read consumer identity
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
BaseOS 86 MB/s | 2.3 MB 00:00
AppStream 129 MB/s | 5.8 MB 00:00
Dependencies resolved.
=============================================================================================
Package Architecture Version Repository Size
=============================================================================================
Installing:
bind-utils x86_64 32:9.11.13-3.el8 AppStream 443 k
Installing dependencies:
bind-libs x86_64 32:9.11.13-3.el8 AppStream 171 k
bind-libs-lite x86_64 32:9.11.13-3.el8 AppStream 1.2 M
bind-license noarch 32:9.11.13-3.el8 AppStream 100 k
python3-bind noarch 32:9.11.13-3.el8 AppStream 147 k
Transaction Summary
=============================================================================================
Install 5 Packages
Total size: 2.0 M
Installed size: 4.7 M
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Installing : bind-license-32:9.11.13-3.el8.noarch 1/5
Installing : bind-libs-lite-32:9.11.13-3.el8.x86_64 2/5
Installing : bind-libs-32:9.11.13-3.el8.x86_64 3/5
Installing : python3-bind-32:9.11.13-3.el8.noarch 4/5
Installing : bind-utils-32:9.11.13-3.el8.x86_64 5/5
Running scriptlet: bind-utils-32:9.11.13-3.el8.x86_64 5/5
Verifying : bind-libs-32:9.11.13-3.el8.x86_64 1/5
Verifying : bind-libs-lite-32:9.11.13-3.el8.x86_64 2/5
Verifying : bind-license-32:9.11.13-3.el8.noarch 3/5
Verifying : bind-utils-32:9.11.13-3.el8.x86_64 4/5
Verifying : python3-bind-32:9.11.13-3.el8.noarch 5/5
Installed products updated.
Installed:
bind-libs-32:9.11.13-3.el8.x86_64 bind-libs-lite-32:9.11.13-3.el8.x86_64
bind-license-32:9.11.13-3.el8.noarch bind-utils-32:9.11.13-3.el8.x86_64
python3-bind-32:9.11.13-3.el8.noarch
Complete!
[root@localhost ~]# which host
/usr/bin/host
host
[root@localhost ~]# host www.baidu.com
www.baidu.com is an alias for www.a.shifen.com.
www.a.shifen.com has address 182.61.200.6
www.a.shifen.com has address 182.61.200.7
nslookup
[root@localhost ~]# host www.baidu.com
www.baidu.com is an alias for www.a.shifen.com.
www.a.shifen.com has address 182.61.200.6
www.a.shifen.com has address 182.61.200.7
[root@localhost ~]# nslookup www.baidu.com
Server: 114.114.114.114
Address: 114.114.114.114#53
Non-authoritative answer:
www.baidu.com canonical name = www.a.shifen.com.
Name: www.a.shifen.com
Address: 182.61.200.7
Name: www.a.shifen.com
Address: 182.61.200.6
netstat //用于查看网络状态
//显示路由表
[root@localhost ~]# 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
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.237.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
//以数字方式显示路由表
[root@localhost ~]# netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
0.0.0.0 192.168.237.2 0.0.0.0 UG 0 0 0 eth0
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
192.168.237.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
//显示建立的tcp连接
[root@localhost ~]# netstat -t
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 36 localhost.localdoma:ssh 192.168.237.1:55936 ESTABLISHED
tcp 0 416 localhost.localdoma:ssh 192.168.237.1:55504 ESTABLISHED
//显示udp连接
[root@localhost ~]# 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@localhost ~]# 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
tcp6 0 0 [::]:ssh [::]:* LISTEN
Active UNIX domain sockets (only servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ACC ] SEQPACKET LISTENING 22751 /run/udev/control
unix 2 [ ACC ] SEQPACKET LISTENING 22797 /run/systemd/coredump
unix 2 [ ACC ] STREAM LISTENING 22845 /run/lvm/lvmpolld.socket
unix 2 [ ACC ] STREAM LISTENING 30055 /run/user/0/systemd/private
unix 2 [ ACC ] STREAM LISTENING 30064 /run/user/0/bus
unix 2 [ ACC ] STREAM LISTENING 27018 /var/run/vmware/guestServicePipe
unix 2 [ ACC ] STREAM LISTENING 26173 /var/lib/sss/pipes/private/sbus-monitor
unix 2 [ ACC ] STREAM LISTENING 26210 /var/lib/sss/pipes/private/sbus-dp_implicit_files.995
unix 2 [ ACC ] STREAM LISTENING 25268 /run/dbus/system_bus_socket
unix 2 [ ACC ] STREAM LISTENING 25271 /var/run/.heim_org.h5l.kcm-socket
unix 2 [ ACC ] STREAM LISTENING 26301 /var/lib/sss/pipes/nss
unix 2 [ ACC ] STREAM LISTENING 22506 /run/systemd/private
unix 2 [ ACC ] STREAM LISTENING 12783 /run/systemd/journal/stdout
Active Bluetooth connections (only servers)
Proto Destination Source State PSM DCID SCID IMTU OMTU Security
Proto Destination Source State Channel
//显示监听指定的套接字的进程的进程号及进程名
[root@localhost ~]# netstat -p
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 36 localhost.localdoma:ssh 192.168.237.1:55936 ESTABLISHED 2525/sshd: root [pr
Active UNIX domain sockets (w/o servers)
Proto RefCnt Flags Type State I-Node PID/Program name Path
unix 10 [ ] DGRAM 12800 1/systemd /run/systemd/journal/dev-log
unix 2 [ ] DGRAM 30051 1577/systemd /run/user/0/systemd/notify
......
unix 2 [ ] DGRAM 47019 2678/NetworkManager
unix 3 [ ] STREAM CONNECTED 47013 2678/NetworkManager
Active Bluetooth connections (w/o servers)
Proto Destination Source State PSM DCID SCID IMTU OMTU Security
Proto Destination Source State Channel
//显示所有状态的连接
[root@localhost ~]# 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 36 localhost.localdoma:ssh 192.168.237.1:55936 ESTABLISHED
tcp6 0 0 [::]:ssh [::]:* LISTEN
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags Type State I-Node Path
unix 10 [ ] DGRAM 12800 /run/systemd/journal/dev-log
unix 2 [ ACC ] SEQPACKET LISTENING 22751 /run/udev/control
......
unix 2 [ ] DGRAM 47019
unix 3 [ ] STREAM CONNECTED 47013
Active Bluetooth connections (servers and established)
Proto Destination Source State PSM DCID SCID IMTU OMTU Security
Proto Destination Source State Channel
//常用选项
-antlp
[root@localhost ~]# 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 1042/sshd
tcp 0 36 192.168.237.128:22 192.168.237.1:55936 ESTABLISHED 2525/sshd: root [pr
tcp6 0 0 :::22 :::* LISTEN 1042/sshd
ss //网络状态查看工具，取代netstat
//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
//常用组合：
[root@localhost ~]# ss -ant
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 0.0.0.0:22 0.0.0.0:*
ESTAB 0 36 192.168.237.128:22 192.168.237.1:55936
LISTEN 0 128 [::]:22 [::]:*
[root@localhost ~]# ss -tanl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 0.0.0.0:22 0.0.0.0:*
LISTEN 0 128 [::]:22 [::]:*
[root@localhost ~]# ss -antlp
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 0.0.0.0:22 0.0.0.0:* users:(("sshd",pid=1042,fd=5))
LISTEN 0 128 [::]:22 [::]:* users:(("sshd",pid=1042,fd=7))
[root@localhost ~]# ss -aut
Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port
tcp LISTEN 0 128 0.0.0.0:ssh 0.0.0.0:*
tcp ESTAB 0 36 192.168.237.128:ssh 192.168.237.1:55936
tcp LISTEN 0 128 [::]:ssh [::]:*
//常见的FILTER：(可小写不能简写)
[root@localhost ~]# ss -ant state ESTABLISHED
Recv-Q Send-Q Local Address:Port Peer Address:Port
0 36 192.168.237.128:22 192.168.237.1:55936
[root@localhost ~]# ss -ant state LISTENING
Recv-Q Send-Q Local Address:Port Peer Address:Port
0 128 0.0.0.0:22 0.0.0.0:*
0 128 [::]:22 [::]:*
常见端口:
| 常用服务 | 默认端口号 |
|---|---|
| http | 80/tcp |
| https | 443/tcp |
| ssh | 22/tcp |
| ftp | 20,21/tcp |
| mysql | 3306/tcp |
| rsync | 873/rsync |
| redis | 6379/tcp |