DHCP addressing mode on an interface
If you configure Dynamic Host Configuration Protocol (DHCP) on an interface on the Fortigate, the FortiGate automatically broadcasts a DHCP request from the interface. The interface is configured with the IP address, any DNS server addresses, and the default gateway address that the DHCP server provides.
DHCP IPv6 is similar to DHCP IPv4, except no default gateway option is defined because a host learns the gateway using router advertisement messages. Also, there are no WINS servers because it is obsolete. For more information about DHCP IPv6, see RFC 3315.
Configuring DHCP - GUI
You can configure DHCP for an interface in Network > Interfaces in the FortiGate GUI. Select the interface from the list, and select DHCP in the Addressing mode. The following table describes the DHCP status information when DHCP is configured for an interface.
|
Field |
Description |
|---|---|
|
Status |
Displays DHCP status messages as the interface connects to the DHCP server and gets addressing information. Select Status to refresh the addressing mode status message.
Status can be one of the following values:
|
|
Obtained IP/Netmask |
The IP address and netmask leased from the DHCP server. This is only displayed if the Status is connected. |
|
Renew |
Select this to renew the DHCP license for this interface. This is only displayed if the Status is connected. |
|
Expiry Date |
The time and date when the leased IP address and netmask is no longer valid for the interface. The IP address is returned to the pool to be allocated to the next user request for an IP address. This is only displayed if the Status is connected. |
|
Default Gateway |
The IP address of the gateway defined by the DHCP server. This is displayed only if the Status is connected, and if Receive default gateway from server is selected. |
|
Distance |
Enter the administrative distance for the default gateway retrieved from the DHCP server. The administrative distance is an integer from 1 to 255, and specifies the relative priority of a route when there are multiple routes to the same destination. A lower administrative distance indicates a more preferred route. |
|
Retrieve default gateway from server |
Enable this to retrieve a default gateway IP address from the DHCP server. The default gateway is added to the static routing table. |
|
Override internal DNS |
Enable this to use the DNS addresses retrieved from the DHCP server instead of the DNS server IP addresses on the DNS page.
When VDOMs are enabled, you can override the internal DNS only on the management VDOM. |