SonicWALL TZ 190 DHCP Server Persistence Overview

Network > DHCP Server
279
SonicOS Enhanced 4.0 Administrator Guide
clients on the network, it provides vendor-specific configuration and service information. The
“DHCP Option Numbers” on page 294 provides a list of DHCP options by RFC-assigned option
number.
Benefits
The SonicWALL DHCP server options feature provides a simple interface for selecting DHCP
options by number or name, making the DHCP configuration process quick, easy, and
compliant with RFC-defined DHCP standards.
How Does the SonicWALL DHCP Server Options Feature Work?
The SonicWALL DHCP server options feature allows definition of DHCP options using a drop-
down menu based on RFC-defined option numbers, allowing administrators to easily create
DHCP objects and object groups, and configure DHCP generic options for dynamic and static
DHCP lease scopes. Once defined, the DHCP option is included in the options field of the
DHCP message, which is then passed to DHCP clients on the network, describing the network
configuration and service(s) available.
Supported Standards
The SonicWALL DHCP server options feature supports the following standards:
• RFC 2131 - Dynamic Host Configuration Protocol
• RFC 2132 - DHCP Options and BOOTP Vendor Extensions
DHCP Server Persistence Overview
• “What is DHCP Server Persistence?” on page 279
• “Benefits” on page 279
• “How Does DHCP Server Persistence Work?” on page 280
What is DHCP Server Persistence?
DHCP server persistence is the ability of the firewall save DHCP lease information and to
provide the client with a predictable IP address that does not conflict with another use on the
network, even after a client reboot.
Benefits
DHCP server persistence provides a seamless experience when a user reboots a workstation.
The DHCP lease information is saved, and the user retains the same workstation IP address.
When a firewall is restarted, usually due to maintenance or an upgrade, DHCP server
persistence provides the following benefits:
• IP address uniqueness: Lease information is stored in flash memory, so the risk of
assigning the same IP address to multiple users is nullified.
• Ease of use: By saving the lease information in the flash memory, the user’s connections
are automatically restored.