CentOS恢復DHCP出廠設置需區分客戶端和服務端，具體操作如下：
/etc/dhcp/dhclient.conf（若存在），或將其重命名備份：sudo mv /etc/dhcp/dhclient.conf /etc/dhcp/dhclient.conf.bak
sudo dhclient -r # 釋放租約
sudo dhclient # 重新獲取IP
sudo systemctl restart network
sudo systemctl stop isc-dhcp-server
/etc/dhcp/dhcpd.conf：sudo cp /path/to/backup/dhcpd.conf /etc/dhcp/dhcpd.conf
sudo yum reinstall dhcp-server
sudo systemctl start isc-dhcp-server
sudo systemctl status isc-dhcp-server
rpm -q dhcp-server檢查。
