Configure an Interface as a DHCP Client

Configure a firewall interface as a DHCP 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.
  1. Configure an interface as a DHCP client.
    1. Select
      Network
      Interfaces
      .
    2. On the
      Ethernet
      tab or the
      VLAN
      tab,
      Add
      a Layer 3 interface or select a configured Layer 3 interface that you want to be a DHCP client.
    3. Select the
      IPv4
      tab and, for
      Type
      , select
      DHCP Client
      .
    4. Select
      Enable
      .
    5. (
      Optional
      ) Enable the option to
      Automatically create default route pointing to default gateway provided by server
      enabled 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.
    6. (
      Optional
      ) Enable the option to
      Send Hostname
      to 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 indicates
      system-hostname
      , which is the firewall hostname that you set in
      Device
      Setup
      Management
      General Settings
      . 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 (_).
      dhcp-client-send-hostname.png
    7. (
      Optional
      ) Enter a
      Default 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.
      The
      Default Route Metric
      for 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 default
      Metric
      is 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 to
      Automatically create default route pointing to default gateway provided by server
      , select a virtual router, add a static route for a Layer 3 interface, change the
      Metric
      (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’s
      Metric
      to a value less than 10 (such as 6), the route in the route table is updated to indicate the configured metric of 6.
    8. (
      Optional
      ) Enable the option to
      Show DHCP Client Runtime Info
      to see all of the settings the client inherited from its DHCP server.
  2. Commit your changes.
    Click
    OK
    and
    Commit
    .
    The Ethernet interface should now indicate
    Dynamic-DHCP Client
    as its
    IP Address
    on the
    Ethernet
    tab.
  3. (
    Optional
    ) See which interfaces on the firewall are configured as DHCP clients.
    1. Select
      Network
      Interfaces
      Ethernet
      and check the
      IP Address
      to see which interfaces indicate DHCP Client.
    2. Select
      Network
      Interfaces
      VLAN
      and check the
      IP Address
      to see which interfaces indicate DHCP Client.

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