查看本机网卡名称：

 1zhangcong@lenovo-e47-1no6e7d:~$ ip a
 21: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
 3    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
 4    inet 127.0.0.1/8 scope host lo
 5       valid_lft forever preferred_lft forever
 6    inet6 ::1/128 scope host 
 7       valid_lft forever preferred_lft forever
 82: enp0s25: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
 9    link/ether 04:7d:7b:d4:de:89 brd ff:ff:ff:ff:ff:ff
10    inet 192.168.0.91/24 brd 192.168.0.255 scope global noprefixroute enp0s25
11       valid_lft forever preferred_lft forever
12    inet6 fe80::67d:7bff:fed4:de89/64 scope link 
13       valid_lft forever preferred_lft forever

可以看到本地网卡名称为：enp0s25

修改网络配置：

Ubuntu20.04的配置IP地址的文件位于 /etc/netplan 文件夹中，里面有一个扩展名为yaml的配置文件。编辑它。

1zhangcong@lenovo-e47-1no6e7d:~$ sudo vim /etc/netplan/01-network-manager-all.yaml

示例如下：

 1# Let NetworkManager manage all devices on this system
 2network:
 3  version: 2
 4  renderer: NetworkManager
 5  ethernets:
 6    enp0s25: # 网卡名称
 7      dhcp4: no # 关闭dhcp
 8
 9      addresses: [192.168.0.91/24] # 设置本机IP及掩码
10      gateway4: 192.168.0.1 # 设置网关
11      nameservers:
12        addresses: [114.114.114.114, 223.5.5.5, 8.8.8.8] # 设置DNS；223.5.5.5 是阿里云的dns

使上面的配置生效：

1zhangcong@lenovo-e47-1no6e7d:~$ sudo netplan apply