linux 用了好多年了，每次設置靜態ip都上網查，就是記不住。唉~

cat /etc/network/interfaces

auto lo
iface lo inet loopback

#auto eth0
#iface eth0 inet dhcp

auto eth0
iface eth0 inet static
    address 10.39.249.201
    netmask 255.255.255.0
    gateway 10.39.249.254

設置 DNS

cat /etc/resolvconf/resolv.conf.d/base 
nameserver 223.5.5.5
nameserver 223.6.6.6

sudo resolvconf -u # 生效