Firewall as a DHCP Server and Client
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Firewall as a DHCP Server and Client

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Firewall as a DHCP Server and Client

The firewall can function as a DHCP server and as a DHCP client. Dynamic Host Configuration Protocol, RFC 2131, is designed to support IPv4 and IPv6 addresses. The Palo Alto Networks® implementation of DHCP server supports IPv4 addresses only.
The firewall DHCP server operates in the following manner:
  • When the DHCP server receives a DHCPDISCOVER message from a client, the server replies with a DHCPOFFER message containing all of the predefined and user-defined options in the order they appear in the configuration. The client selects the options it needs and responds with a DHCPREQUEST message.
  • When the server receives a DHCPREQUEST message from a client, the server replies with its DHCPACK message containing only the options specified in the request.
The firewall DHCP client operates in the following manner:
  • When the DHCP client receives a DHCPOFFER from the server, the client automatically caches all of the options offered for future use, regardless of which options it had sent in its DHCPREQUEST.
  • By default and to save memory consumption, the client caches only the first value of each option code if it receives multiple values for a code.
  • There is no maximum length for DHCP messages unless the DHCP client specifies a maximum in option 57 in its DHCPDISCOVER or DHCPREQUEST messages.