聊聊 Ubuntu 18.04 静态IP设置

在Ubuntu 17.10 中 引入了一种新的命令行配置实用工具。它实用YAML格式来配置和描述网络设置。

Ubuntu 18.04 默认使用该工具。

关于YAML格式，跟json和xml类似，语法是不能用TAB（切记），空格代表层级，key:value  “:”后面加一个英文空格，区分大小写。这几个是入门容易犯的错误。wtf ，这是一种倒退吗。简单了解请点击下面：

 YAML 语言教程

想学习netplan的，可以去官网（好的文档都是英文的）

https://netplan.io/

使用netplan 搞定所有网络配置，简单粗暴

（1）编辑 /etc/netplan/*yaml文件

sudo vim /etc/netplan/50-cloud-init.yaml 
 

# This file is generated from information provided by
# the datasource.  Changes to it will not persist across an instance.
# To disable cloud-init's network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
        #renderer:NetworkManager    
    ethernets:
        ens33:
            addresses: [192.168.21.131/24]
            dhcp4: no
            gateway4: 192.168.21.2
            #optional: true
            nameservers:   
             addresses: [127.0.0.53, 202.106.0.20]
             search: [localdomain]
            optional: true 
    version: 2
~

 我的是VMware的虚拟机下环境

addresses: 是一个数组，使用，号分开可以配置多个IP，一般一个就够了。格式[0.0.0.0/24,1.1.1.1/26]还可以使用-0.0.0./24

dhcp4:true 使用dhcp动态获取  这里使用no 试了false 不可以 ,难道true的反义词不是 false 是no

gateway4: ipv4网管

nameservers: dns 配置 这里的addresses 前面需要空格，表示nameservers的子项

  addresses:[127.0.0.53, 202.106.0.20]  // dns地址

  search:[localdomain]  //虚拟机所在的domain

（2）立即生效

sudo netplan apply

（3）ping 测试

ping www.baidu.com 看是否可以ping通

ubuntu@s1:~$ ping baidu.com
ping: baidu.com: Name or service not known
ubuntu@s1:~$ ping www.baidu.com
PING www.a.shifen.com (119.75.216.20) 56(84) bytes of data.
64 bytes from 127.0.0.1 (119.75.216.20): icmp_seq=1 ttl=128 time=4.71 ms
64 bytes from 127.0.0.1 (119.75.216.20): icmp_seq=2 ttl=128 time=4.75 ms
64 bytes from 127.0.0.1 (119.75.216.20): icmp_seq=3 ttl=128 time=5.36 ms
64 bytes from 127.0.0.1 (119.75.216.20): icmp_seq=5 ttl=128 time=6.87 ms
64 bytes from 127.0.0.1 (119.75.216.20): icmp_seq=6 ttl=128 time=7.90 ms
64 bytes from 127.0.0.1 (119.75.216.20): icmp_seq=7 ttl=128 time=6.19 ms
64 bytes from 127.0.0.1 (119.75.216.20): icmp_seq=8 ttl=128 time=8.19 ms
^C
--- www.a.shifen.com ping statistics ---
8 packets transmitted, 7 received, 12% packet loss, time 7024ms
rtt min/avg/max/mdev = 4.715/6.286/8.190/1.324 ms

ping baidu.com 居然不行 ，好扎心  。   

 

另外这里用到了一些网络知识，简单说一下

（1）ifconfig查看IP地址 和子网掩码

192.168.21.131/24 这个24 就是 255.255.255.0 的子网掩码

ubuntu@s1:~$ ifconfig
ens33: flags=4163  mtu 1500
        inet 192.168.21.131  netmask 255.255.255.0  broadcast 192.168.21.255
        inet6 fe80::20c:29ff:fe9f:70a  prefixlen 64  scopeid 0x20
        ether 00:0c:29:9f:07:0a  txqueuelen 1000  (Ethernet)
        RX packets 64989  bytes 5945447 (5.9 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2997  bytes 410154 (410.1 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 834083  bytes 53476526 (53.4 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 834083  bytes 53476526 (53.4 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

 

（2）dns查看

cat /etc/resolv.conf

# This file is managed by man:systemd-resolved(8). Do not edit.
# 上面这句话 说明  这个配置文件 由系统配置，不能修改，使用netplan配置。
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "systemd-resolve --status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.

nameserver 127.0.0.53
search localdomain

（3）查看网关

使用 netstat -rn 或者 route -n

ubuntu@s1:~$ netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         192.168.21.2    0.0.0.0         UG        0 0          0 ens33
192.168.21.0    0.0.0.0         255.255.255.0   U         0 0          0 ens33
ubuntu@s1:~$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.21.2    0.0.0.0         UG    0      0        0 ens33
192.168.21.0    0.0.0.0         255.255.255.0   U     0      0        0 ens33
ubuntu@s1:~$ 

0.0.0.0 对应的 gateway就是网关

对应 gateway4的配置