Configure an Interface as a DHCPv4 Client
Configure a firewall interface as a DHCPv4 client.
Before configuring a firewall interface as a DHCP client, make sure you have configured a Layer 3 interface (Ethernet, Ethernet subinterface, VLAN, VLAN subinterface, aggregate, or aggregate subinterface) and the interface is assigned to a virtual router and a zone. Configure an interface as a DHCP client if you need to use DHCP to request an IPv4 address for the interface.
If the firewall interface needs a dynamic IPv6 address, Configure an Interface as a DHCPv6 Client (with or without prefix delegation).
- Configure an interface as a DHCP client.
- On theEthernettab or theVLANtab,Adda Layer 3 interface or select a configured Layer 3 interface that you want to be a DHCPv4 client.
- Select theIPv4tab and, forType, selectDHCP Client.
- (Optional) Enable the option toAutomatically create default route pointing to default gateway provided by serverenabled by default). Enabling this option causes the firewall to create a static route to the default gateway, which is useful when clients try to access many destinations that do not need to have routes maintained in a route table on the firewall.
- (Optional) Enable the option toSend Hostnameto assign a hostname to the DHCP client interface and send that hostname (Option 12) to a DHCP server, which can then register the hostname with the DNS server. The DNS server can then automatically manage hostname-to-dynamic IP address resolutions. External hosts can identify the interface by its hostname. The default value indicatessystem-hostname, which is the firewall hostname that you set in. Alternatively, enter a hostname for the interface, which can be a maximum of 64 characters, including uppercase and lowercase letters, numbers, period (.), hyphen (-), and underscore (_).DeviceSetupManagementGeneral Settings
- (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 enable the option toAutomatically create default route pointing to default gateway provided by server, select a virtual router, add a static route for a Layer 3 interface, change theMetric(which defaults to 10) to a value greater than 10 (for this example, 100) and Commit your changes. In the route table, the route’s metric will not indicate 100. Instead, it will indicate the default value of 10, as expected, because 10 takes precedence over the configured value of 100. However, if you change the static route’sMetricto a value less than 10 (such as 6), the route in the route table is updated to indicate the configured metric of 6.
- (Optional) Enable the option toShow DHCP Client Runtime Infoto see all of the settings the client inherited from its DHCP server.
- Commit your changes.ClickOKandCommit.The Ethernet interface should now indicateDynamic-DHCP Clientas itsIP Addresson theEthernettab.
- (Optional) See which interfaces on the firewall are configured as DHCP clients.
- Selectand check theNetworkInterfacesEthernetIP Addressto see which interfaces indicate DHCP Client.
- Selectand check theNetworkInterfacesVLANIP Addressto see which interfaces indicate DHCP Client.
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