# for debain in /etc/network/interfaces
# you can find your network adapter with ip a
# no need for network or broadcast address when you set your netmask right
auto <your-networkadapter>
allow-hotplug <your-networkadapter>
iface <your-networkadapter> inet static
address 192.168.X.X
netmask 255.255.255.X
gateway 192.168.X.X
ip address add 172.16.251.1/24 brd + dev wlan0:0