If you want to use the SonicWall security appliance’s DHCP server, select enable DHCP Server on the Network | DHCP Server page. Select Enable Conflict Detection to turn on automatic DHCP scope conflict detection on each zone.
Static entries are IP addresses assigned to servers requiring permanent IP settings. Because SonicOS Enhanced allows multiple DHCP scopes per interface, there is no requirement that the subnet range is attached to the interface when configuring DHCP scopes.
SonicOS Standard and Enhanced
Login to the SonicWall ,click MANAGE.
Navigate to the Network | DHCP Server page.
Make sure Enable DHCP Server is checked.
Click Add Static button to bring up the Static DHCP Configuration window.
Check Enable this DHCP Scope/Entry.
As prompted, enter a name for this mapping, the computer's assigned IP address, the corresponding MAC address, etc.