"config system dhcp reserved-address
set ip 192.168.1.10
set mac 00:21:70:8B:79:DD
ip is the ip address you are assigning to the client
mac is the mac address of the network card or wireless network card
you MUST put end and then hit enter or this change wont save.
You must enter the mac address with the 00:21:70:8B:79:DD format, you cannot use the 00-21-70-8B-79-DD format"