方法一：图像化界面，右上角
图标→编辑链接→DSL→......
方法二：命令行
总结一下遇到的问题及解决：
ip addr
sudo -i
systemctl
systemctl NetworkManager-wait-online restart
systemctl restart NetworkManager-wait-online
systemctl restart NetworkManager-wait-online
pppoeconf
pon dsl-privider
cat /etc/ppp/peers/
pon dsl-provider
vim /etc/ppp/peers/dsl-provider 并去掉文件中不能识别的那一行东西
pon dsl-privider
ip addr如果出现下图界面则表示连接成功
