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Table of Contents

About the Documentation

E Series and JunosE Documentation and Release Notes
Audience
E Series and JunosE Text and Syntax Conventions
Obtaining Documentation
Documentation Feedback
Requesting Technical Support

How DHCP Relay Works

DHCP Relay and BOOTP Relay Overview

Rate of DHCP Client Packets Processed by DHCP Relay Overview

Manually Configuring the Maximum Rate of Client Packets Processed Per Second by DHCP Relay

DHCP Option 60 Attribute for Traffic Forwarding

Using Option 60 Strings to Forward Client Traffic to Specific DHCP Servers

DHCP Option 82 Attribute and Suboptions for Traffic Forwarding

DHCP Relay Agent Information Option (Option 82) Suboption Values Overview

Format of the JunosE Data Field in the Vendor-Specific Suboption for Option 82

Configuration

Configuration Tasks for DHCP Relay Functions

Configuring DHCP Relay Settings

Enabling DHCP Relay
Removing Access Routes from Routing Tables and NVS
Treating All Packets as Originating at Trusted Sources
Assigning the Giaddr to Source IP Address
Protecting Against Spoofed Giaddr and Relay Agent Option Values
Using the Giaddr to Identify the Primary Interface for Dynamic Subscriber Interfaces

Configuring DHCP Relay Proxy

Enabling DHCP Relay Proxy
Use the First Offer from a DHCP Server
Set a Timeout for DHCP Client Renewal Messages

Managing Host Routes Using DHCP Relay Proxy

Selecting the DHCP Server Response
Behavior for Bound Clients and Address Renewals

Broadcast Flag Settings for DHCP Relay

Using the Broadcast Flag Setting to Control Transmission of DHCP Reply Packets
Interaction of DHCP Relay Broadcast Flag with the Layer 2 Unicast Transmission Method

Preventing Host Routes Installation

Preventing DHCP Relay from Installing Host Routes by Default
Including Relay Agent Option Values in the PPPoE Remote Circuit ID

Configuring DHCP Option 60 for Relaying Packets

Configuring the DHCP Relay Option 60 Attribute for Traffic Forwarding
Relaying DHCP Packets That Originate from a Cable Modem

Configuring DHCP Option 82 and Suboptions for Relaying Packets

Configuring the DHCP Relay Agent Option 82 Settings

Configuring Relay Agent Option 82 Information
Preventing Option 82 Information from Being Stripped from Trusted Client Packets
Configuring Relay Agent Information Option (Option 82) Suboption Values

Using the set dhcp relay agent Command to Enable Option 82 Suboption Support

Using the set dhcp relay agent sub-option Command to Enable Option 82 Suboption Support

Unicast Tranmission of DHCP Replies

Configuring the Layer 2 Unicast Transmission Method for Reply Packets to DHCP Clients

Example: Preventing Installation of Host Routes
Example: Using DHCP Relay Option 82 to Pass IEEE 802.1p Values to DHCP Servers

Configuration Commands

interface ip
ip route
ip share-interface
ip source-prefix
ip unnumbered
service dhcp-local
set dhcp relay
set dhcp relay agent sub-option
set dhcp relay assign-giaddr-source-ip
set dhcp relay broadcast-flag-replies
set dhcp relay giaddr-selects-interface
set dhcp relay layer2-unicast-replies
set dhcp relay max-client-packet-rate
set dhcp relay options
set dhcp relay override
set dhcp relay preserve-trusted-client-option
set dhcp relay proxy send-first-offer
set dhcp relay proxy timeout
set dhcp relay trust-all
set dhcp vendor-option

Administration

Configuring Baselines for DHCP Relay and Relay Proxy Statistics

Setting Baselines for DHCP Statistics

Setting a Baseline for DHCP Relay and Relay Proxy
Setting a Baseline for DHCP Proxy Server Statistics
Setting a Baseline for DHCP External Server Statistics
Setting a Baseline for DHCP Local Server Statistics

Monitoring DHCP Relay and Relay Proxy Settings

Monitoring DHCP Relay Configuration Information
Monitoring DHCP Option 60 Information
Monitoring DHCP Packet Capture Settings

Monitoring DHCP Relay and Relay Proxy Statistics

Monitoring DHCP Relay Statistics
Monitoring DHCP Relay Proxy Statistics

Monitoring Commands

show dhcp relay
show dhcp relay proxy statistics
show dhcp relay statistics
show dhcp vendor-option

Index