Points to remember:

All branches can act as DHCP servers with gateway as the DHCP Lan IP_Address.

Both branches or all branches can act as relay and forward DHCP requests to some other server

We must go in appliance tab>select appliance (Branch)>configuration>networking icon > DHCP

Next, use below menus to configure DHCP server and/or DHCP relay:

1) Lease Profile

We can create Lease profile for DHCP which include parameters (DHCP Lease Profile is options and is needed only when really know what you are doing):

There are default values for Lease profile, which you can change as per your need. Since this is Lab, so I configured less value.

Please note: Rebind timers should be more than twice the renew timers

2) Options Profile for IPv4 (Only for DHCP Servers):

The options profile defines the settings required by the DHCP server to allocate IPv4 addresses to DHCP clients. It defines the following parameters:

Domain. Domain from where IP addresses will be allocated.

DNS server. DNS server which will be leased to DHCP clients.

Router. Default GW Router which will be advertised to DHCP clients.

Here's an example of the Option Profile:

3) Address Pool

Address Pool is the IP address list from which IP addresses are dynamically allocated by the DHCP server to DHCP clients.

In the Director view, go to Configuration > Devices > Devices. Select an organization from the left navigation panel and a device from the dashboard. This takes you to the Appliance view.

In the Networking tab, go to DHCP > Server > Address Pools. Click the V4 and then "+" button to open new pool creation menu.

As a minimum you need to configure Subnet Mask, Server Identifier, Options Profile and give at least one list of Addresses.

Example of the Address Pool:

(Optional) If you want to create an exception for the addresses you can use Exclude Address menu. For example, you may want to lease addresses from the pool 192.168.10.0/24 but we know that certain devices will have statically assigned IPs 192.168.10.1-192.168.10.10 and they shouldn't be leased to DHCP Clients. 

Example of the Exclude Addresses Pool, which we don’t want to assign via DHCP, so that our IP lease will start from 192.168.10.11:

4) DHCP servers for IPv4

Now, we are ready to create a DHCP server and attach it to the network interfaces of the VOS™. 

You need to give it a name, Server Identifier and an Options Profile. Lease Profile is optional.

Example:

Click Match tab to select interfaces on which DHCP server will be working. Select interfaces/networks which should be used by DHCP Server.

Example:

Click Address Allocation tab to configure the IP addresses which will be allocated to DHCP clients.

Select an address pool which you want to use

On the Options tab you can enable logging of the new allocations and DHCP renewals:

CLI configuration (for advanced users)

We can also achieve DHCP configuration from CLI. But it is best practice to do it from a template workflow.

Screen with example of the configuration of a DHCP server:

CLI Commands to Clear DHCP Lease