Juniper EX3400 Specification sheet

DHCP and Other System Services Feature Guide
for EX2300, EX3400, and EX4300 Switches
Modified: 2017-07-26
Copyright © 2017, Juniper Networks, Inc.

Juniper Networks, Inc.
1133 Innovation Way
Sunnyvale, California 94089
USA
408-745-2000
www.juniper.net
Juniper Networks, Junos, Steel-Belted Radius, NetScreen, and ScreenOS are registered trademarks of Juniper Networks, Inc. in the United
States and other countries. The Juniper Networks Logo, the Junos logo, and JunosE are trademarks of Juniper Networks, Inc. All other
trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.
Juniper Networks assumes no responsibility for any inaccuracies in this document. Juniper Networks reserves the right to change, modify,
transfer, or otherwise revise this publication without notice.
DHCP and Other System Services Feature Guide for EX2300, EX3400, and EX4300 Switches
Copyright © 2017, Juniper Networks, Inc.
All rights reserved.
The information in this document is current as of the date on the title page.
YEAR 2000 NOTICE
Juniper Networks hardware and software products are Year 2000 compliant. Junos OS has no known time-related limitations through the
year 2038. However, the NTP application is known to have some difficulty in the year 2036.
END USER LICENSE AGREEMENT
The Juniper Networks product that is the subject of this technical documentation consists of (or is intended for use with) Juniper Networks
software. Use of such software is subject to the terms and conditions of the End User License Agreement (“EULA”) posted at
http://www.juniper.net/support/eula.html. By downloading, installing or using such software, you agree to the terms and conditions of
that EULA.
Copyright © 2017, Juniper Networks, Inc.ii

Table of Contents
AbouttheDocumentation............................................xv
DocumentationandReleaseNotes.................................xv
SupportedPlatforms.............................................xv
UsingtheExamplesinThisManual.................................xv
MergingaFullExample.......................................xvi
MergingaSnippet...........................................xvi
Documentation Conventions .....................................xvii
DocumentationFeedback........................................xix
RequestingTechnicalSupport.....................................xix
Self-Help Online Tools and Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . xix
OpeningaCasewithJTAC.....................................xx
Part 1 DHCP and DHCP Relay
Chapter1 DHCPServices.....................................................3
Understanding DHCP Services for Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
DHCPClient/ServerModel.........................................3
UsingDHCP.....................................................4
DHCP Relay Servers and DHCP Servers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Legacy DHCP and Extended DHCP for Server Versions . . . . . . . . . . . . . . . . . . 5
ConfiguringDHCPonaSwitch......................................6
HowDHCPWorks................................................6
Configuring DHCP Services (J-Web Procedure) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Configuring DHCP Services (J-Web Procedure) on EX Series Switches . . . . . . 7
Configuring DHCP Services on EX4300 Switches (J-Web Procedure) . . . . . . 10
Configuring a Switch as a DHCP Server (CLI Procedure) . . . . . . . . . . . . . . . . . . . . 14
Configuring the Switch as a Local DHCP Server . . . . . . . . . . . . . . . . . . . . . . . . 15
Configuring a DHCP Client (CLI Procedure) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Configuring a DHCP SIP Server (CLI Procedure) . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Chapter2 DHCPLocalServer.................................................21
Extended DHCP Local Server Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Interaction Among the DHCP Client, Extended DHCP Local Server, and
Address-AssignmentPools....................................24
Providing DHCP Client Configuration Information . . . . . . . . . . . . . . . . . . . . . . 25
MinimalConfigurationforClients...................................26
DHCP Local Server and Address-Assignment Pools . . . . . . . . . . . . . . . . . . . . 26
Example: Minimum Extended DHCP Local Server Configuration . . . . . . . . . . . . . . 27
Overriding Default DHCP Local Server Configuration Settings . . . . . . . . . . . . . . . 28
Deleting DHCP Local Server and DHCP Relay Override Settings . . . . . . . . . . . . . . 30
iiiCopyright © 2017, Juniper Networks, Inc.

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
Chapter3 DHCPv6LocalServer..............................................39
DHCPv6LocalServerOverview.......................................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
Chapter4 DHCPRelayAgent................................................45
ExtendedDHCPRelayAgentOverview.................................46
Interaction Among the DHCP Relay Agent, DHCP Client, and DHCP
Servers ....................................................47
DHCPLivenessDetection.........................................48
Configuring an Extended DHCP Relay Server on EX Series Switches (CLI
Procedure) ....................................................49
Example: Minimum DHCP Relay Agent Configuration . . . . . . . . . . . . . . . . . . . . . . 50
DHCPRelayProxyOverview...........................................51
Interaction Among DHCP Relay Proxy, DHCP Client, and DHCP Servers . . . . 51
EnablingDHCPRelayProxyMode......................................52
Example: Configuring DHCP Relay Agent Selective Traffic Processing Based on
DHCPOptionStrings............................................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
ConfiguringOption82Information..................................61
IncludingaPrefixinDHCPOptions.................................63
Including a Textual Description in DHCP Options . . . . . . . . . . . . . . . . . . . . . . 65
TrustingOption82Information........................................67
Overriding the Default DHCP Relay Configuration Settings . . . . . . . . . . . . . . . . . . 68
OverridingOption82Information.......................................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
ConfiguringNamedServerGroups.....................................79
Configuring Active Server Groups to Apply a Common DHCP Relay Agent
Configuration to Named Server Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
DisablingDHCPRelay...............................................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

Suppressing DHCP Access, Access-Internal, and Destination Routes . . . . . . . . . . 81
Preventing DHCP from Installing Access, Access-Internal, and Destination Routes
byDefault .....................................................82
Chapter5 DHCPv6RelayAgent..............................................85
DHCPv6RelayAgentOverview........................................85
Inserting DHCPv6 Interface-ID Option (Option 18) In DHCPv6 Packets . . . . . . . . 86
Verifying and Managing DHCPv6 Relay Configuration . . . . . . . . . . . . . . . . . . . . . . 87
Chapter 6 Configuring Groups of DHCP Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Grouping Interfaces with Common DHCP Configurations . . . . . . . . . . . . . . . . . . . 89
Guidelines for Configuring Interface Ranges for Groups of DHCP Interfaces . . . . 90
Configuring Group-Specific DHCP Local Server Options . . . . . . . . . . . . . . . . . . . . 91
Configuring Group-Specific DHCP Relay Options . . . . . . . . . . . . . . . . . . . . . . . . . 92
Chapter7 DHCPLivenessDetection..........................................95
DHCPLivenessDetectionOverview....................................95
Configuring Detection of DHCP Local Server Client Connectivity . . . . . . . . . . . . . 96
Configuring Detection of DHCP Relay or DHCP Relay Proxy Client
Connectivity ...................................................98
Chapter8 ManagingDHCPClients...........................................101
Using External AAA Authentication Services with DHCP . . . . . . . . . . . . . . . . . . . 101
Configuring Passwords for Usernames . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Creating Unique Usernames for DHCP Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Specifying the Maximum Number of DHCP Clients Per Interface . . . . . . . . . . . . 106
DHCP Local Server Handling of Client Information Request Messages . . . . . . . . 107
Enabling Processing of Client Information Requests . . . . . . . . . . . . . . . . . . . . . . 108
Chapter 9 Forcing Dynamic Reconfiguration of Clients from a DHCP Local Server . . 111
Understanding Dynamic Reconfiguration of Extended DHCP Local Server
Clients ........................................................111
DefaultClient/ServerInteraction...................................111
Dynamic Client/Server Interaction for DHCPv4 . . . . . . . . . . . . . . . . . . . . . . . 112
Dynamic Client/Server Interaction for DHCPv6 . . . . . . . . . . . . . . . . . . . . . . . 112
Manually Forcing the Local Server to Initiate the Reconfiguration
Process ...................................................113
Action Taken for Events That Occur During a Reconfiguration . . . . . . . . . . . . 113
Configuring Dynamic Client Reconfiguration of Extended Local Server
Clients........................................................114
Requesting DHCP Local Server to Initiate Reconfiguration of Client Bindings . . . 116
Configuring Dynamic Reconfiguration Attempts for DHCP Clients . . . . . . . . . . . . 117
Configuring Deletion of the Client When Dynamic Reconfiguration Fails . . . . . . . 118
Configuring Reconfiguration of the Client on Receipt of RADIUS-Initiated
Disconnect ....................................................119
vCopyright © 2017, Juniper Networks, Inc.
Table of Contents

Chapter 10 Managing IP Address Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Address-AssignmentPoolsOverview...................................121
Configuring How the Extended DHCP Local Server Determines Which
Address-AssignmentPooltoUse..................................122
Example: Extended DHCP Local Server Configuration with Optional Pool
Matching......................................................123
DHCPAutoLogoutOverview.........................................124
AutoLogoutOverview...........................................124
How DHCP Identifies and Releases Clients . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Option 60 and Option 82 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
How DHCP Relay Agent Uses Option 82 for Auto Logout . . . . . . . . . . . . . . . . . . . 126
Automatically Logging Out DHCP Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Assign a Specific IP Address to a Client Using DHCP Option 50 and DHCPv6
IA_NAOption..................................................128
Multiple Address Assignment for DHCPv6 Clients . . . . . . . . . . . . . . . . . . . . . . . . 129
Part 2 Other System Services
Chapter 11 Configuring Packet Forwarding Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Configuring Port-based LAN Broadcast Packet Forwarding . . . . . . . . . . . . . . . . . 133
Part 3 Configuration Statements and Operational Commands
Chapter 12 Configuration Statements (DHCP and DHCP Relay) . . . . . . . . . . . . . . . . . . 137
access(DynamicAccessRoutes)......................................141
access-internal (Dynamic Access-Internal Routes) . . . . . . . . . . . . . . . . . . . . . . . 142
active-server-group ................................................144
allow-no-end-option (DHCP Relay Agent) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
allow-snooped-clients..............................................146
always-write-giaddr ................................................147
always-write-option-82.............................................148
attempts(DHCPLocalServer).......................................149
authentication(DHCPLocalServer)...................................150
authentication(DHCPRelayAgent)....................................151
bfd ..............................................................152
circuit-id(DHCPRelayAgent)........................................153
circuit-type(DHCPLocalServer).....................................156
circuit-type(DHCPRelayAgent)......................................157
clear-on-abort(DHCPLocalServer)...................................158
client-discover-match (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
client-id(DHCPLocalServer)........................................160
client-id(DHCPRelayAgent).........................................161
delegated-pool (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
delimiter(DHCPLocalServer)........................................163
delimiter(DHCPRelayAgent)........................................165
detection-time ....................................................166
dhcp(DHCPClient)................................................167
dhcp-local-server..................................................168
dhcp-relay........................................................174
Copyright © 2017, Juniper Networks, Inc.vi
DHCP and Other System Services Feature Guide for EX2300, EX3400, and EX4300 Switches

dhcpv6(DHCPLocalServer).........................................183
dhcpv6(DHCPRelayAgent).........................................187
disable-relay ......................................................193
domain-name(DHCPLocalServer)...................................194
domain-name(DHCPRelayAgent)...................................196
domain-search ....................................................197
drop(DHCPRelayAgentOption).....................................198
dynamic-profile (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
dynamic-profile (DHCP Relay Agent) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
external-authority..................................................201
failure-action .....................................................202
forward-snooped-clients (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . 203
forward-snooped-clients (DHCP Relay Agent) . . . . . . . . . . . . . . . . . . . . . . . . . . 204
group(DHCPLocalServer)..........................................205
group(DHCPRelayAgent)..........................................208
holddown-interval ..................................................211
include-irb-and-l2..................................................212
interface(DHCPLocalServer)........................................214
interface(DHCPRelayAgent)........................................216
interface-client-limit (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
interface-client-limit (DHCP Relay Agent) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
interface-delete (Subscriber Management or DHCP Client Management) . . . . . 221
interface-name (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
interface-name(DHCPRelayAgent)..................................223
ip-address-first....................................................224
layer2-unicast-replies ..............................................225
lease-time .......................................................226
liveness-detection .................................................227
local-server-group (DHCP Relay Agent Option) . . . . . . . . . . . . . . . . . . . . . . . . . 228
mac-address(DHCPLocalServer)....................................229
mac-address(DHCPRelayAgent)....................................230
maximum-hop-count...............................................231
maximum-lease-time (DHCP).......................................232
method..........................................................233
minimum-interval .................................................234
minimum-receive-interval...........................................235
minimum-wait-time ...............................................236
multiplier.........................................................237
name-server......................................................238
next-hop (Dynamic Access-Internal Routes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
no-adaptation ....................................................240
no-allow-snooped-clients ...........................................241
no-bind-on-request (DHCP Relay Agent) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
no-listen .........................................................243
no-vlan-interface-name ............................................244
option-60(DHCPLocalServer)......................................246
option-60(DHCPRelayAgent).......................................247
option-82 (DHCP Local Server Authentication) . . . . . . . . . . . . . . . . . . . . . . . . . 248
option-82 (DHCP Local Server Pool Matching) . . . . . . . . . . . . . . . . . . . . . . . . . . 249
viiCopyright © 2017, Juniper Networks, Inc.
Table of Contents

option-82(DHCPRelayAgent)......................................250
option-number (DHCP Relay Agent Option) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
overrides(DHCPLocalServer).......................................252
overrides(DHCPRelayAgent).......................................254
password(DHCPLocalServer).......................................256
password(DHCPRelayAgent).......................................258
pool(DHCPLocalServerOverrides)...................................259
pool-match-order .................................................260
preference (Subscriber Management) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
prefix(DHCPRelayAgent)..........................................262
process-inform....................................................263
proxy-mode ......................................................265
radius-disconnect (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266
rapid-commit (DHCPv6 Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
reconfigure(DHCPLocalServer).....................................268
relay-agent-interface-id (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
relay-agent-interface-id (DHCPv6 Relay Agent) . . . . . . . . . . . . . . . . . . . . . . . . . 270
relay-agent-remote-id (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
relay-agent-remote-id (DHCPv6 Relay Agent Username) . . . . . . . . . . . . . . . . . . 272
relay-option(DHCPRelayAgent).....................................273
relay-option-82 ...................................................274
relay-server-group (DHCP Relay Agent Option) . . . . . . . . . . . . . . . . . . . . . . . . . . 275
replace-ip-source-with .............................................276
retransmission-attempt.............................................277
retransmission-interval .............................................278
route-suppression (DHCP Local Server and Relay Agent) . . . . . . . . . . . . . . . . . . 279
routing-instance-name (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . 280
routing-instance-name (DHCP Relay Agent) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
send-release-on-delete (DHCP Relay Agent) . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
server (DNS, Port, and TFTP Service) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
server-address....................................................286
server-group......................................................287
server-identifier ...................................................288
service-profile (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
service-profile(DHCPRelayAgent)...................................290
session-mode .....................................................291
sip-server ........................................................292
source-address-giaddr .............................................293
static-binding.....................................................294
strict(DHCPLocalServer)..........................................295
threshold(detection-time)..........................................296
threshold(transmit-interval).........................................297
timeout(DHCPLocalServer)........................................298
token(DHCPLocalServer)..........................................299
trace(DHCPRelayAgent)..........................................300
traceoptions(DHCPServer).........................................301
traceoptions (DNS, Port, and TFTP Packet Forwarding) . . . . . . . . . . . . . . . . . . . 304
transmit-interval ..................................................306
trigger(DHCPLocalServer).........................................307
Copyright © 2017, Juniper Networks, Inc.viii
DHCP and Other System Services Feature Guide for EX2300, EX3400, and EX4300 Switches

trust-option-82 ...................................................308
use-interface-description ...........................................309
use-primary(DHCPLocalServer).....................................311
use-primary(DHCPRelayAgent).....................................312
use-vlan-id .......................................................314
user-prefix(DHCPLocalServer)......................................316
username-include (DHCP Local Server) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 318
username-include (DHCP Relay Agent) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
version(BFD).....................................................322
wins-server(System)...............................................323
Chapter 13 Configuration Statements (Forwarding Options) . . . . . . . . . . . . . . . . . . . . 325
description(ForwardingOptions).....................................326
helpers ..........................................................327
interface (DNS, Port, and TFTP Packet Forwarding or Relay Agent) . . . . . . . . . . 330
no-listen .........................................................331
port(PacketForwarding)...........................................332
server (DNS, Port, and TFTP Service) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334
traceoptions (DNS, Port, and TFTP Packet Forwarding) . . . . . . . . . . . . . . . . . . . 335
Chapter 14 Operational Commands (DHCP and DHCP Relay) . . . . . . . . . . . . . . . . . . . . 337
cleardhcprelaybinding.............................................339
cleardhcpserverbinding............................................342
cleardhcprelaystatistics...........................................345
cleardhcpserverstatistics..........................................348
cleardhcpv6relaybinding...........................................350
cleardhcpv6serverbinding..........................................353
cleardhcpv6relaystatistics.........................................356
cleardhcpv6serverstatistics........................................358
clearsystemservicesdhcpbinding....................................359
clearsystemservicesdhcpconflict...................................360
clear system services dhcp statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
requestdhcpserverreconfigure......................................362
requestdhcpv6serverreconfigure....................................364
requestsystemreboot..............................................366
showdhcprelaybinding.............................................372
showdhcpserverbinding...........................................378
showdhcprelaystatistics...........................................385
showdhcpserverstatistics..........................................389
showdhcpv6relaybinding..........................................393
showdhcpv6serverbinding.........................................401
showdhcpv6relaystatistics.........................................407
showdhcpv6serverstatistics.........................................411
showrouteextensive...............................................414
showrouteprotocol................................................432
showsystemservicesdhcpbinding...................................445
showsystemservicesdhcpconflict...................................448
showsystemservicesdhcpglobal....................................449
showsystemservicesdhcppool......................................451
show system services dhcp statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 454
ixCopyright © 2017, Juniper Networks, Inc.
Table of Contents

Copyright © 2017, Juniper Networks, Inc.x
DHCP and Other System Services Feature Guide for EX2300, EX3400, and EX4300 Switches

List of Figures
Part 1 DHCP and DHCP Relay
Chapter1 DHCPServices.....................................................3
Figure1:DHCPClient/ServerModel.....................................4
Figure2:DHCPFour-StepTransfer......................................6
Chapter2 DHCPLocalServer.................................................21
Figure3:DHCPOptionsDataFlow.....................................34
xiCopyright © 2017, Juniper Networks, Inc.

Copyright © 2017, Juniper Networks, Inc.xii
DHCP and Other System Services Feature Guide for EX2300, EX3400, and EX4300 Switches

List of Tables
AbouttheDocumentation..........................................xv
Table1:NoticeIcons................................................xvii
Table 2: Text and Syntax Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xviii
Part 1 DHCP and DHCP Relay
Chapter1 DHCPServices.....................................................3
Table 3: Legacy DHCP and Extended DHCP Server Hierarchy Levels . . . . . . . . . . . 5
Table 4: DHCP Service Configuration Pages Summary . . . . . . . . . . . . . . . . . . . . . . 8
Table 5: DHCP Service Configuration Pages Summary for EX4300 Switches . . . . 10
Table6:DHCPClientSettings.........................................18
Chapter2 DHCPLocalServer.................................................21
Table 7: Comparing the Extended DHCP Local Server to the Traditional DHCP
LocalServer....................................................23
Table 8: Information in Authentication Grant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 9: Unsupported Opaque DHCP Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Chapter3 DHCPv6LocalServer..............................................39
Table 10: RADIUS Attributes and VSAs for DHCPv6 Local Server . . . . . . . . . . . . . 40
Chapter4 DHCPRelayAgent................................................45
Table 11: Actions for DHCP Relay Agent Snooped Packets When DHCP Snooping
IsEnabled.....................................................78
Table 12: Actions for DHCP Relay Agent Snooped Packets When DHCP Snooping
IsDisabled.....................................................78
Table 13: Actions for Snooped BOOTREPLY Packets . . . . . . . . . . . . . . . . . . . . . . . 78
Chapter 9 Forcing Dynamic Reconfiguration of Clients from a DHCP Local Server . . 111
Table 14: Action Taken for Events That Occur During a Reconfiguration . . . . . . . . 113
Chapter 10 Managing IP Address Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Table 15: DHCP Relay Agent Option 82 Value for Auto Logout . . . . . . . . . . . . . . . 126
Part 3 Configuration Statements and Operational Commands
Chapter 14 Operational Commands (DHCP and DHCP Relay) . . . . . . . . . . . . . . . . . . . . 337
Table 16: clear dhcp relay statistics Output Fields . . . . . . . . . . . . . . . . . . . . . . . . 346
Table 17: show dhcp relay binding Output Fields . . . . . . . . . . . . . . . . . . . . . . . . . . 373
Table 18: show dhcp server binding Output Fields . . . . . . . . . . . . . . . . . . . . . . . . 379
Table 19: show dhcp relay statistics Output Fields . . . . . . . . . . . . . . . . . . . . . . . . 386
Table 20: show dhcp server statistics Output Fields . . . . . . . . . . . . . . . . . . . . . . 390
Table 21: show dhcpv6 relay binding Output Fields . . . . . . . . . . . . . . . . . . . . . . . 394
xiiiCopyright © 2017, Juniper Networks, Inc.

Table 22: show dhcpv6 server binding Output Fields . . . . . . . . . . . . . . . . . . . . . . 402
Table 23: show dhcpv6 relay statistics Output Fields . . . . . . . . . . . . . . . . . . . . . 408
Table 24: show dhcpv6 server statistics Output Fields . . . . . . . . . . . . . . . . . . . . . 412
Table 25: show route extensive Output Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
Table 26: show system services dhcp binding Output Fields . . . . . . . . . . . . . . . 445
Table 27: show system services dhcp conflict Output Fields . . . . . . . . . . . . . . . . 448
Table 28: show system services dhcp global Output Fields . . . . . . . . . . . . . . . . 449
Table 29: show system services dhcp pool Output Fields . . . . . . . . . . . . . . . . . . 451
Table 30: show system services dhcp statistics Output Fields . . . . . . . . . . . . . . 454
Copyright © 2017, Juniper Networks, Inc.xiv
DHCP and Other System Services Feature Guide for EX2300, EX3400, and EX4300 Switches

About the Documentation
•Documentation and Release Notes on page xv
•Supported Platforms on page xv
•Using the Examples in This Manual on page xv
•Documentation Conventions on page xvii
•Documentation Feedback on page xix
•Requesting Technical Support on page xix
Documentation and Release Notes
To obtain the most current version of all Juniper Networks®technical documentation,
see the product documentation page on the Juniper Networks website at
http://www.juniper.net/techpubs/.
If the information in the latest release notes differs from the information in the
documentation, follow the product Release Notes.
Juniper Networks Books publishes books by Juniper Networks engineers and subject
matter experts. These books go beyond the technical documentation to explore the
nuances of network architecture, deployment, and administration. The current list can
be viewed at http://www.juniper.net/books.
Supported Platforms
For the features described in this document, the following platforms are supported:
•EX Series
Using the Examples in This Manual
If you want to use the examples in this manual, you can use the load merge or the load
merge relative command. These commands cause the software to merge the incoming
configuration into the current candidate configuration. The example does not become
active until you commit the candidate configuration.
If the example configuration contains the top level of the hierarchy (or multiple
hierarchies), the example is a full example. In this case, use the load merge command.
xvCopyright © 2017, Juniper Networks, Inc.

If the example configuration does not start at the top level of the hierarchy, the example
isasnippet. In this case, use the load merge relative command. These procedures are
described in the following sections.
Merging a Full Example
To merge a full example, follow these steps:
1. From the HTML or PDF version of the manual, copy a configuration example into a
text file, save the file with a name, and copy the file to a directory on your routing
platform.
For example, copy the following configuration to a file and name the file ex-script.conf.
Copy the ex-script.conf file to the /var/tmp directory on your routing platform.
system {
scripts {
commit {
file ex-script.xsl;
}
}
}
interfaces {
fxp0 {
disable;
unit 0 {
family inet {
address 10.0.0.1/24;
}
}
}
}
2. Merge the contents of the file into your routing platform configuration by issuing the
load merge configuration mode command:
[edit]
user@host# load merge /var/tmp/ex-script.conf
load complete
Merging a Snippet
To merge a snippet, follow these steps:
1. From the HTML or PDF version of the manual, copy a configuration snippet into a text
file, save the file with a name, and copy the file to a directory on your routing platform.
For example, copy the following snippet to a file and name the file
ex-script-snippet.conf. Copy the ex-script-snippet.conf file to the /var/tmp directory
on your routing platform.
commit {
file ex-script-snippet.xsl; }
Copyright © 2017, Juniper Networks, Inc.xvi
DHCP and Other System Services Feature Guide for EX2300, EX3400, and EX4300 Switches

2. Move to the hierarchy level that is relevant for this snippet by issuing the following
configuration mode command:
[edit]
user@host# edit system scripts
[edit system scripts]
3. Merge the contents of the file into your routing platform configuration by issuing the
load merge relative configuration mode command:
[edit system scripts]
user@host# load merge relative /var/tmp/ex-script-snippet.conf
load complete
For more information about the load command, see CLI Explorer.
Documentation Conventions
Table 1 on page xvii defines notice icons used in this guide.
Table 1: Notice Icons
DescriptionMeaningIcon
Indicates important features or instructions.Informational note
Indicates a situation that might result in loss of data or hardware damage.Caution
Alerts you to the risk of personal injury or death.Warning
Alerts you to the risk of personal injury from a laser.Laser warning
Indicates helpful information.Tip
Alerts you to a recommended use or implementation.Best practice
Table 2 on page xviii defines the text and syntax conventions used in this guide.
xviiCopyright © 2017, Juniper Networks, Inc.
About the Documentation

Table 2: Text and Syntax Conventions
ExamplesDescriptionConvention
To enter configuration mode, type the
configure command:
user@host> configure
Represents text that you type.Bold text like this
user@host> show chassis alarms
No alarms currently active
Represents output that appears on the
terminal screen.
Fixed-width text like this
•A policy term is a named structure
that defines match conditions and
actions.
•Junos OS CLI User Guide
•RFC 1997, BGP Communities Attribute
•Introduces or emphasizes important
new terms.
•Identifies guide names.
•Identifies RFC and Internet draft titles.
Italic text like this
Configure the machine’s domain name:
[edit]
root@# set system domain-name
domain-name
Represents variables (options for which
you substitute a value) in commands or
configuration statements.
Italic text like this
•To configure a stub area, include the
stub statement at the [edit protocols
ospf area area-id] hierarchy level.
•The console port is labeled CONSOLE.
Represents names of configuration
statements, commands, files, and
directories; configuration hierarchy levels;
or labels on routing platform
components.
Text like this
stub <default-metric metric>;Encloses optional keywords or variables.< > (angle brackets)
broadcast | multicast
(string1 |string2 |string3)
Indicates a choice between the mutually
exclusive keywords or variables on either
side of the symbol. The set of choices is
often enclosed in parentheses for clarity.
| (pipe symbol)
rsvp { # Required for dynamic MPLS onlyIndicates a comment specified on the
same line as the configuration statement
to which it applies.
# (pound sign)
community name members [
community-ids ]
Encloses a variable for which you can
substitute one or more values.
[ ] (square brackets)
[edit]
routing-options {
static {
route default {
nexthop address;
retain;
}
}
}
Identifies a level in the configuration
hierarchy.
Indention and braces ( { } )
Identifies a leaf statement at a
configuration hierarchy level.
; (semicolon)
GUI Conventions
Copyright © 2017, Juniper Networks, Inc.xviii
DHCP and Other System Services Feature Guide for EX2300, EX3400, and EX4300 Switches

Table 2: Text and Syntax Conventions (continued)
ExamplesDescriptionConvention
•In the Logical Interfaces box, select
All Interfaces.
•To cancel the configuration, click
Cancel.
Represents graphical user interface (GUI)
items you click or select.
Bold text like this
In the configuration editor hierarchy,
select Protocols>Ospf.
Separates levels in a hierarchy of menu
selections.
>(bold right angle bracket)
Documentation Feedback
We encourage you to provide feedback, comments, and suggestions so that we can
improve the documentation. You can provide feedback by using either of the following
methods:
•Online feedback rating system—On any page of the Juniper Networks TechLibrary site
at http://www.juniper.net/techpubs/index.html, simply click the stars to rate the content,
and use the pop-up form to provide us with information about your experience.
Alternately, you can use the online feedback form at
http://www.juniper.net/techpubs/feedback/.
•E-mail—Send your comments to [e-mail]. Include the document
or topic name, URL or page number, and software version (if applicable).
Requesting Technical Support
Technical product support is available through the Juniper Networks Technical Assistance
Center (JTAC). If you are a customer with an active J-Care or Partner Support Service
support contract, or are covered under warranty, and need post-sales technical support,
you can access our tools and resources online or open a case with JTAC.
•JTAC policies—For a complete understanding of our JTAC procedures and policies,
review the JTAC User Guide located at
http://www.juniper.net/us/en/local/pdf/resource-guides/7100059-en.pdf.
•Product warranties—For product warranty information, visit
http://www.juniper.net/support/warranty/.
•JTAC hours of operation—The JTAC centers have resources available 24 hours a day,
7 days a week, 365 days a year.
Self-Help Online Tools and Resources
For quick and easy problem resolution, Juniper Networks has designed an online
self-service portal called the Customer Support Center (CSC) that provides you with the
following features:
xixCopyright © 2017, Juniper Networks, Inc.
About the Documentation

•Find CSC offerings: http://www.juniper.net/customers/support/
•Search for known bugs: http://www2.juniper.net/kb/
•Find product documentation: http://www.juniper.net/techpubs/
•Find solutions and answer questions using our Knowledge Base: http://kb.juniper.net/
•Download the latest versions of software and review release notes:
http://www.juniper.net/customers/csc/software/
•Search technical bulletins for relevant hardware and software notifications:
http://kb.juniper.net/InfoCenter/
•Join and participate in the Juniper Networks Community Forum:
http://www.juniper.net/company/communities/
•Open a case online in the CSC Case Management tool: http://www.juniper.net/cm/
To verify service entitlement by product serial number, use our Serial Number Entitlement
(SNE) Tool: https://tools.juniper.net/SerialNumberEntitlementSearch/
Opening a Case with JTAC
You can open a case with JTAC on the Web or by telephone.
•Use the Case Management tool in the CSC at http://www.juniper.net/cm/.
•Call 1-888-314-JTAC (1-888-314-5822 toll-free in the USA, Canada, and Mexico).
For international or direct-dial options in countries without toll-free numbers, see
http://www.juniper.net/support/requesting-support.html.
Copyright © 2017, Juniper Networks, Inc.xx
DHCP and Other System Services Feature Guide for EX2300, EX3400, and EX4300 Switches