Configure an Interface as a DHCP Client
Before configuring a firewall interface as a DHCP client, make sure you have configured a Layer 3 Ethernet or Layer 3 VLAN interface, and the interface is assigned to a virtual router and a zone. Perform this task if you need to use DHCP to request an IPv4 address for an interface on your firewall.
- Configure an interface as a DHCP client.
- On theEthernettab or theVLANtab,Addan interface, or select a configured interface, that you want to be a DHCP client.
- Select theIPv4tab; forType, selectDHCP Client.
- (Optional) SelectAutomatically create default route pointing to default gateway provided by server. This setting is enabled by default. It causes the firewall to create a static route to the default gateway, which is useful when clients are trying to access many destinations that do not need to have routes maintained in a routing table on the firewall.
- (Optional) Enter aDefault Route Metric(priority level) for the route between the firewall and the DHCP server (range is 1 to 65,535; default is 10). A route with a lower number has higher priority during route selection. For example, a route with a metric of 10 is used before a route with a metric of 100.TheDefault Route Metricfor the route between the firewall and the DHCP server is 10 by default. If the static default route 0.0.0.0/0 uses the DHCP interface as its egress interface, that route’s defaultMetricis also 10. Therefore, there are two routes with a metric of 10 and the firewall can randomly choose one of the routes one time and the other route another time.Suppose you selectAutomatically create default route pointing to default gateway provided by serverand you select a virtual router, and add a static route for a Layer 3 interface and you change theMetric(which defaults to 10) to a value greater than 10 (let’s say 100). You Commit. In the route table, the route’s metric does not indicate 100; it indicates the default of 10 as expected because 10 takes precedence over the configured value of 100. But if you change the static route’sMetricto a value less than 10 (let’s say 6), the route in the route table is updated to indicate the configured metric of 6.
- (Optional) SelectShow DHCP Client Runtime Infoto see all of the settings the client has inherited from its DHCP server.
- Commit your changes.ClickOKandCommit.Now the Ethernet interface indicatesDynamic-DHCP Clientin itsIP Addressfield on theEthernettab.
- (Optional) See which interfaces on the firewall are configured as DHCP clients.
- Selectand look in theNetworkInterfacesEthernetIP Addressfield to see which interfaces indicate DHCP Client.
- Selectand look in theNetworkInterfacesVLANIP Addressfield to see which interfaces indicate DHCP Client.