Fortinet FortiGate FortiGate-800 Installation And Configuration Manual page 159

Network configuration
FortiGate-800 Installation and Configuration Guide
You can add multiple scopes to an interface so that the DHCP server added to that
interface can supply IP addresses to computers on multiple subnets.
Add multiple scopes if the DHCP server receives DHCP requests from subnets that
are not connected directly to the FortiGate unit. In this case, the DHCP requests are
sent to the FortiGate unit through DHCP relay. DHCP relay packets contain DHCP
relay IP, which is the IP address of the subnet from which the DHCP relay received the
request.
If the DHCP request received by the DHCP server is not forwarded by a DHCP relay,
the DHCP server decides which scope to use based on the IP address of the interface
that received the DHCP request; usually the scope with the same subnet as the
interface.
If the DHCP request received by the server is forwarded by a DHCP relay, the relay IP
is used to select the scope.
To add a scope to a DHCP server
1 Go to System > Network > DHCP.
2 Select Address Scope.
3 Select an interface.
You must configure the interface as a DHCP server before it can be selected.
4 Select New to add an address scope.
5 Configure the address scope.
Scope Name
IP Pool
Netmask
Lease Duration
Domain
Default Route
6 Select Advanced if you want to configure Advanced Options.
DNS IP
WINS Server IP
Exclusion Range Optionally enter up to 4 exclusion ranges of IP addresses within the IP pool
7 Select OK.
Enter the address scope name.
Enter the starting IP and ending IP for the range of IP addresses that this
DHCP server assigns to DHCP clients.
Enter the netmask that the DHCP server assigns to the DHCP clients.
Enter the interval, in days, hours and minutes, after which a DHCP client
must ask the DHCP server for a new address.
If you select Unlimited, DHCP leases never expire.
Optionally enter in the domain that the DHCP server assigns to the DHCP
clients.
Enter the default route to be assigned to DHCP clients. The default route
must be on the same subnet as the IP pool.
Enter the addresses of up to 3 DNS servers that the DHCP server assigns
to the DHCP clients.
Add the IP addresses of one or two WINS servers to be assigned to DHCP
clients.
that cannot be assigned to DHCP clients.
Configuring DHCP services
159