Juniper EX3400

Configuring a Token for DHCP Local Server Authentication . . . . . . . . . . . . . . . . . . 31
Centrally Configured Opaque DHCP Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Data Flow for RADIUS-Sourced DHCP Options . . . . . . . . . . . . . . . . . . . . . . . 34
Multiple VSA 26-55 Instances Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 35
DHCP Options That Cannot Be Centrally Configured . . . . . . . . . . . . . . . . . . . 35
Port Number Requirements for DHCP Firewall Filters . . . . . . . . . . . . . . . . . . . . . . 36
Verifying and Managing DHCP Local Server Configuration . . . . . . . . . . . . . . . . . . . 37
Chapter 3 DHCPv6 Local Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
DHCPv6 Local Server Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Enabling DHCPv6 Rapid Commit Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Specifying the Delegated Address Pool for IPv6 Prefix Assignment . . . . . . . . . . . 42
Preventing Binding of Clients That Do Not Support Reconfigure Messages . . . . . 42
Verifying and Managing DHCPv6 Local Server Configuration . . . . . . . . . . . . . . . . 43
Chapter 4 DHCP Relay Agent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Extended DHCP Relay Agent Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Interaction Among the DHCP Relay Agent, DHCP Client, and DHCP
Servers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
DHCP Liveness Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Configuring an Extended DHCP Relay Server on EX Series Switches (CLI
Procedure) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Example: Minimum DHCP Relay Agent Configuration . . . . . . . . . . . . . . . . . . . . . . 50
DHCP Relay Proxy Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Interaction Among DHCP Relay Proxy, DHCP Client, and DHCP Servers . . . . 51
Enabling DHCP Relay Proxy Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Example: Configuring DHCP Relay Agent Selective Traffic Processing Based on
DHCP Option Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Using Layer 2 Unicast Transmission for DHCP Packets . . . . . . . . . . . . . . . . . . . . . 58
Sending Release Messages When Clients Are Deleted . . . . . . . . . . . . . . . . . . . . . 58
Disabling Automatic Binding of Stray DHCP Requests . . . . . . . . . . . . . . . . . . . . . 59
Using DHCP Relay Agent Option 82 Information . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Configuring Option 82 Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Including a Prefix in DHCP Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Including a Textual Description in DHCP Options . . . . . . . . . . . . . . . . . . . . . . 65
Trusting Option 82 Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Overriding the Default DHCP Relay Configuration Settings . . . . . . . . . . . . . . . . . . 68
Overriding Option 82 Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Changing the Gateway IP Address (giaddr) Field to the giaddr of the DHCP Relay
Agent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Replacing the DHCP Relay Request and Release Packet Source Address . . . . . . . 72
Enabling and Disabling DHCP Snooped Packets Support for DHCP Relay
Agent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Configuring DHCP Snooped Packets Forwarding Support for DHCP Relay
Agent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Configuring Named Server Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Configuring Active Server Groups to Apply a Common DHCP Relay Agent
Configuration to Named Server Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Disabling DHCP Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Verifying and Managing DHCP Relay Configuration . . . . . . . . . . . . . . . . . . . . . . . . 81
Copyright © 2017, Juniper Networks, Inc.iv
DHCP and Other System Services Feature Guide for EX2300, EX3400, and EX4300 Switches