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The IP address of a specific client can be assigned based on its device MAC address and connection type. During a server reboot, you can specify a specific IP address by using a DHCP scope, which allows each device to receive the same IP address.
In order to reserve DHCP in Fortigate, you will need to create a new DHCP reservation.
Reserve an IP Address using GUI
1. Login into the FTG | Network > Interface. Double click on a interface to edit it.
2. In the Edit interface windows, scroll down under DHCP section click to expand Advanced options.
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3. Scroll down under IP Address Assignment Rules. Click Create New button.
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4. Enter the MAC address of a server or client then set a reserve IP address.
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Reserve an IP Address using DHCP list
The second way, you can hover on an interface then select View DHCP Clients option.
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Search a client using its MAC address. Select it then create a new reservation.
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Click OK button and you’re done.
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Reserve an IP Address using CLI
1. Get the list of DHCP servers in the FTG.
config system dhcp server
show
gw17 # config system dhcp server
gw17 (server) # show
config system dhcp server
...
next
edit 3
set default-gateway 10.10.0.1
set netmask 255.255.0.0
set interface "internal2"
...
next
2. edit 3 (this is the DHCP scope you want to create the reservation in). Then create a reserve IP.
edit 3
config reserved-address
show
edit 1
set type mac
set ip 10.10.230.5
set mac 48:65:ee:13:da:ab
set description DEV-Server
show
end
gw17 (server) # edit 3
gw17 (3) # config reserved-address
gw17 (reserved-address) # show
gw17 (reserved-address) # edit 1
new entry '1' added
gw17 (1) # set type mac
gw17 (1) # set ip 10.10.230.5
gw17 (1) # set mac 48:65:ee:13:da:ab
gw17 (1) # set description DEV-Server
gw17 (1) # show
config reserved-address
edit 1
set ip 10.10.230.5
set mac 48:65:ee:13:da:ab
set description "DEV-Server"
next
end