assign a static IP address
netsh interface ip set address name="Ethernet 5" static 10.1.2.1 255.255.255.0 10.1.2.1
set a DNS server address
netsh interface ip set dns name="Ethernet 5" static 10.1.2.1
set an alternate DNS server address
netsh interface ip add dns name="Ethernet 5" 8.8.8.8 index=2