H3C s5820x series User manual

H3C S5820X&S5800 Series Ethernet Switches
Layer 3 - IP Services
Configuration Guide
Hangzhou H3C Technologies Co., Ltd.
http://www.h3c.com
Document Version: 6W103-20100716
Product Version: Release 1110

Copyright © 2009-2010, Hangzhou H3C Technologies Co., Ltd. and its licensors
All Rights Reserved
No part of this manual may be reproduced or transmitted in any form or by any means without prior
written consent of Hangzhou H3C Technologies Co., Ltd.
Trademarks
H3C, , Aolynk, , H3Care, , TOP G, , IRF, NetPilot, Neocean, NeoVTL,
SecPro, SecPoint, SecEngine, SecPath, Comware, Secware, Storware, NQA, VVG, V2G, VnG, PSPT,
XGbus, N-Bus, TiGem, InnoVision and HUASAN are trademarks of Hangzhou H3C Technologies Co.,
Ltd.
All other trademarks that may be mentioned in this manual are the property of their respective owners.
Notice
The information in this document is subject to change without notice. Every effort has been made in the
preparation of this document to ensure accuracy of the contents, but all statements, information, and
recommendations in this document do not constitute the warranty of any kind, express or implied.

Preface
The H3C S5800&S5820X documentation set includes 11 configuration guides, which describe the
software features for the S5800&S5820X Series Ethernet Switches and guide you through the software
configuration procedures. These configuration guides also provide configuration examples to help you
apply software features to different network scenarios.
The Layer 3 – IP ServicesConfiguration Guide describes IP services fundamentals and configuration. It
describes how to configure IP addresses, adjust IP parameters, resolve an IP address to a MAC
address, configure DNS, relay IP broadcasts from the specified UDP port, and implement IPv4-IPv6
interoperation.
This preface includes:
zAudience
zDocument Organization
zConventions
zAbout the H3C S5800&S5820X Documentation Set
zObtaining Documentation
zDocumentation Feedback
Audience
This documentation set is intended for:
zNetwork planners
zField technical support and servicing engineers
zNetwork administrators working with the S5800 and S5820X series
Document Organization
The Layer 3 – IP Services Configuration Guide comprises these parts:
ARP Configuration Proxy ARP Configuration ARP Snooping
Configuration IP Addressing Configuration
DHCP Overview DHCP Server
Configuration DHCP Relay Agent Configuration DHCP Client Configuration
DHCP Snooping
Configuration BOOTP Client Configuration IPv4 DNS Configuration IPv6 DNS Configuration
IP Performance
Optimization
Configuration
UDP Helper
Configuration IPv6 Basics Configuration DHCPv6 Configuration
Tunneling Configuration

Conventions
This section describes the conventions used in this documentation set.
Command conventions
Convention Description
Boldface Bold text represents commands and keywords that you enter literally as shown.
italic Italic text represents arguments that you replace with actual values.
[ ] Square brackets enclose syntax choices (keywords or arguments) that are
optional.
{ x | y | ... }
Braces enclose a set of required syntax choices separated by vertical bars,
from which you select one.
[ x | y | ... ]
Square brackets enclose a set of optional syntax choices separated by vertical
bars, from which you select one or none.
{ x | y | ... } *
Asterisk marked braces enclose a set of required syntax choices separated by
vertical bars, from which you select at least one.
[ x | y | ... ] *
Asterisk marked square brackets enclose optional syntax choices separated by
vertical bars, from which you may select multiple choices or none.
&<1-n> The argument or keyword and argument combination before the ampersand (&)
sign can be entered 1 to n times.
# A line that starts with a pound (#) sign is comments.
Symbols
Convention Description
Means reader be extremely careful. Improper operation may cause bodily
injury.
Means reader be careful. Improper operation may cause data loss or damage to
equipment.
Means a complementary description.
About the H3C S5800&S5820X Documentation Set
The H3C S5800&S5820X documentation set also includes:
Category Documents Purposes
Marketing brochures Describe product specifications and benefits.
Product description and
specifications Technology white papers Provide an in-depth description of software features
and technologies.
PSR150-A [ PSR150-D ]
Power Modules User
Manual
Describes the appearances, features, specifications,
installation, and removal of the pluggable 150W power
modules available for the products.
Pluggable module
description
PSR300-12A
[ PSR300-12D1 ] Power
Modules User Manual
Describes the appearances, features, specifications,
installation, and removal of the pluggable 300W power
modules available for the products.

Category Documents Purposes
PSR750-A [ PSR750-D ]
Power Modules User
Manual
Describes the appearances, features, specifications,
installation, and removal of the pluggable 750W power
modules available for the products.
RPS User Manual Describes the appearances, features, and
specifications of the RPS units available for the
products.
LSW1FAN and
LSW1BFAN Installation
Manual
Describes the appearances, specifications,
installation, and removal of the pluggable fan modules
available for the products.
LSW148POEM Module
User Manual
Describes the appearance, features, installation, and
removal of the pluggable PoE module available for the
products.
S5820X [ S5800 ] Series
Ethernet Switches
Interface Cards User
Manual
Describes the models, hardware specifications,
installation, and removal of the interface cards
available for the products.
H3C OAP Cards User
Manual
Describes the benefits, features, hardware
specifications, installation, and removal of the OAP
cards available for the products.
H3C Low End Series
Ethernet Switches
Pluggable Modules
Manual
Describes the models, appearances, and
specifications of the pluggable modules available for
the products.
S5800-60C-PWR
Ethernet Switch Hot
Swappable Power
Module Ordering Guide
Guides you through ordering the hot-swappable power
modules available for the S5800-60C-PWR switches
in different cases.
Power configuration RPS Ordering
Information for H3C
Low-End Ethernet
Switches
Provides the RPS and switch compatibility matrix and
RPS cable specifications.
zS5800 Series
Ethernet Switches
Quick Start
zS5820X Series
Ethernet Switches
Quick Start
zS5800 Series
Ethernet Switches
CE DOC
zS5820X Series
Ethernet Switches
CE DOC
Provides regulatory information and the safety
instructions that must be followed during installation.
Hardware installation
zS5800 Series
Ethernet Switches
Quick Start
zS5820X Series
Ethernet Switches
Quick Start
Guides you through initial installation and setup
procedures to help you quickly set up and use your
device with the minimum configuration.

Category Documents Purposes
zS5800 Series
Ethernet Switches
Installation Manual
zS5820X Series
Ethernet Switches
Installation Manual
Provides a complete guide to hardware installation
and hardware specifications.
Pluggable
SFP[SFP+][XFP]
Transceiver Modules
Installation Guide
Guides you through installing SFP/SFP+/XFP
transceiver modules.
zS5800-60C-PWR
Switch Video
Installation Guide
zS5820X-28C Switch
Video Installation
Guide
Shows how to install the H3C S5800-60C-PWR and
H3C S5820X-28C Ethernet switches.
Configuration guide Describe software features and configuration
procedures.
Software configuration Command reference Provide a quick reference to all available commands.
H3C Series Ethernet
Switches Login
Password Recovery
Manual
Tells how to find the lost password or recover the
password when the login password is lost.
Operations and
maintenance
Release notes
Provide information about the product release,
including the version history, hardware and software
compatibility matrix, version upgrade information,
technical support information, and software upgrading.
Obtaining Documentation
You can access the most up-to-date H3C product documentation on the World Wide Web at
http://www.h3c.com.
Click the links on the top navigation bar to obtain different categories of product documentation:
[Technical Support & Documents > Technical Documents] – Provides hardware installation, software
upgrading, and software feature configuration and maintenance documentation.
[Products & Solutions] – Provides information about products and technologies, as well as solutions.
[Technical Support & Documents > Software Download] – Provides the documentation released with
the software version.
Documentation Feedback
You can e-mail your comments about product documentation to [email protected].
We appreciate your comments.

i
Table of Contents
1 ARP Configuration·····································································································································1-1
ARP Overview·········································································································································1-1
ARP Function ··································································································································1-1
ARP Message Format·····················································································································1-1
ARP Operation ································································································································1-2
ARP Table·······································································································································1-3
Configuring ARP ·····································································································································1-4
Configuring a Static ARP Entry·······································································································1-4
Configuring the Maximum Number of Dynamic ARP Entries for an Interface ································1-4
Setting the Aging Time for Dynamic ARP Entries···········································································1-5
Enabling the ARP Entry Check ·······································································································1-5
Configuration Gratuitous ARP·················································································································1-6
Introduction to Gratuitous ARP········································································································1-6
Configuring Gratuitous ARP············································································································1-7
Displaying and Maintaining ARP·············································································································1-8
ARP Configuration Example···················································································································1-8
2 Proxy ARP Configuration ·························································································································2-1
Proxy ARP Overview·······························································································································2-1
Proxy ARP·······································································································································2-1
Local Proxy ARP ·····························································································································2-2
Enabling Proxy ARP································································································································2-2
Displaying and Maintaining Proxy ARP ··································································································2-3
Proxy ARP Configuration Examples·······································································································2-3
Proxy ARP Configuration Example ·································································································2-3
Local Proxy ARP Configuration Example in Case of Port Isolation ················································2-4
Local Proxy ARP Configuration Example in Isolate-User-VLAN·····················································2-6
3 ARP Snooping Configuration···················································································································3-1
ARP Snooping Overview ························································································································3-1
Introduction······································································································································3-1
Operation of ARP Snooping············································································································3-1
Configuring ARP Snooping·····················································································································3-1
Displaying and Maintaining ARP Snooping····························································································3-2
4 IP Addressing Configuration····················································································································4-1
IP Addressing Overview··························································································································4-1
IP Address Classes·························································································································4-1
Special IP Addresses ······················································································································4-2
Subnetting and Mask·······················································································································4-2
Configuring IP Addresses·······················································································································4-3
Assigning an IP Address to an Interface·························································································4-3

ii
IP Addressing Configuration Example·····························································································4-4
Displaying and Maintaining IP Addressing ·····························································································4-6
5 DHCP Overview··········································································································································5-1
Introduction to DHCP······························································································································5-1
DHCP Address Allocation·······················································································································5-1
Allocation Mechanisms····················································································································5-1
Dynamic IP Address Allocation Process·························································································5-2
IP Address Lease Extension ···········································································································5-3
DHCP Message Format··························································································································5-3
DHCP Options·········································································································································5-4
DHCP Options Overview·················································································································5-4
Introduction to DHCP Options·········································································································5-4
Self-Defined Options ·······················································································································5-5
Protocols and Standards·························································································································5-8
6 DHCP Server Configuration······················································································································6-1
Introduction to DHCP Server ··················································································································6-1
Application Environment··················································································································6-1
DHCP Address Pool························································································································6-2
IP Address Allocation Sequence·····································································································6-3
DHCP Server Configuration Task List ····································································································6-4
Configuring an Address Pool for the DHCP Server················································································6-4
Configuration Task List····················································································································6-4
Creating a DHCP Address Pool······································································································6-5
Configuring an Address Allocation Mode for a Common Address Pool··········································6-5
Configuring Dynamic Address Allocation for an Extended Address Pool·······································6-7
Configuring a Domain Name Suffix for the Client ···········································································6-8
Configuring DNS Servers for the Client···························································································6-9
Configuring WINS Servers and NetBIOS Node Type for the Client················································6-9
Configuring the BIMS Server Information for the Client································································6-10
Configuring Gateways for the Client······························································································6-10
Configuring Option 184 Parameters for the Client with Voice Service··········································6-11
Configuring the TFTP Server and Bootfile Name for the Client····················································6-11
Configuring Self-Defined DHCP Options·······················································································6-12
Enabling DHCP·····································································································································6-13
Enabling the DHCP Server on an Interface··························································································6-14
Applying an Extended Address Pool on an Interface ···········································································6-14
Configuring the DHCP Server Security Functions················································································6-15
Configuration Prerequisites···········································································································6-15
Enabling Unauthorized DHCP Server Detection···········································································6-15
Configuring IP Address Conflict Detection····················································································6-16
Configuring the Handling Mode for Option 82 ······················································································6-16
Displaying and Maintaining the DHCP Server······················································································6-17
DHCP Server Configuration Examples·································································································6-18
Static IP Address Assignment Configuration Example ·································································6-18

iii
Dynamic IP Address Assignment Configuration Example ····························································6-19
Self-Defined Option Configuration Example··················································································6-21
Troubleshooting DHCP Server Configuration·······················································································6-22
7 DHCP Relay Agent Configuration············································································································7-1
Introduction to DHCP Relay Agent ·········································································································7-1
Application Environment··················································································································7-1
Fundamentals··································································································································7-1
DHCP Relay Agent Support for Option 82······················································································7-2
DHCP Relay Agent Configuration Task List···························································································7-3
Configuring the DHCP Relay Agent········································································································7-4
Enabling DHCP ·······························································································································7-4
Enabling the DHCP Relay Agent on an Interface ···········································································7-4
Correlating a DHCP Server Group with a Relay Agent Interface····················································7-4
Configuring the DHCP Relay Agent Security Functions ·································································7-5
Configuring the DHCP Relay Agent to Send a DHCP-Release Request ·······································7-7
Configuring the DHCP Relay Agent to Support Option 82······························································7-8
Displaying and Maintaining DHCP Relay Agent Configuration ······························································7-9
DHCP Relay Agent Configuration Examples························································································7-10
DHCP Relay Agent Configuration Example··················································································7-10
DHCP Relay Agent Option 82 Support Configuration Example····················································7-11
Troubleshooting DHCP Relay Agent Configuration··············································································7-12
8 DHCP Client Configuration·······················································································································8-1
Introduction to DHCP Client····················································································································8-1
Enabling the DHCP Client on an Interface ·····························································································8-1
Displaying and Maintaining the DHCP Client ·························································································8-2
DHCP Client Configuration Example······································································································8-2
9 DHCP Snooping Configuration················································································································9-1
DHCP Snooping Overview······················································································································9-1
Functions of DHCP Snooping ·········································································································9-1
Application Environment of Trusted Ports·······················································································9-2
DHCP Snooping Support for Option 82···························································································9-3
Configuring DHCP Snooping Basic Functions························································································9-4
Configuring DHCP Snooping to Support Option 82················································································9-5
Prerequisites····································································································································9-5
Configuring DHCP Snooping to Support Option 82········································································9-5
Displaying and Maintaining DHCP Snooping ·························································································9-7
DHCP Snooping Configuration Examples ······························································································9-8
DHCP Snooping Configuration Example·························································································9-8
DHCP Snooping Option 82 Support Configuration Example··························································9-8
10 BOOTP Client Configuration················································································································10-1
Introduction to BOOTP Client ···············································································································10-1
BOOTP Application ·······················································································································10-1
Obtaining an IP Address Dynamically···························································································10-2

iv
Protocols and Standards···············································································································10-2
Configuring an Interface to Dynamically Obtain an IP Address Through BOOTP ·······························10-2
Displaying and Maintaining BOOTP Client Configuration·····································································10-3
BOOTP Client Configuration Example··································································································10-3
11 IPv4 DNS Configuration························································································································11-1
DNS Overview·······································································································································11-1
Static Domain Name Resolution ···································································································11-1
Dynamic Domain Name Resolution ······························································································11-1
DNS Proxy·····································································································································11-3
Configuring the IPv4 DNS Client···········································································································11-4
Configuring Static Domain Name Resolution················································································11-4
Configuring Dynamic Domain Name Resolution···········································································11-4
Configuring the DNS Proxy···················································································································11-5
Displaying and Maintaining IPv4 DNS··································································································11-5
IPv4 DNS Configuration Examples·······································································································11-5
Static Domain Name Resolution Configuration Example······························································11-5
Dynamic Domain Name Resolution Configuration Example·························································11-6
DNS Proxy Configuration Example·······························································································11-9
Troubleshooting IPv4 DNS Configuration···························································································11-11
12 IPv6 DNS Configuration························································································································12-1
Introduction to IPv6 DNS ······················································································································12-1
Configuring the IPv6 DNS Client···········································································································12-1
Configuring Static Domain Name Resolution················································································12-1
Configuring Dynamic Domain Name Resolution···········································································12-1
Displaying and Maintaining IPv6 DNS··································································································12-2
IPv6 DNS Configuration Examples·······································································································12-3
Static Domain Name Resolution Configuration Example······························································12-3
Dynamic Domain Name Resolution Configuration Example·························································12-3
13 IP Performance Optimization Configuration·······················································································13-1
Overview···············································································································································13-1
Enabling Reception and Forwarding of Directed Broadcasts to a Directly Connected Network··········13-1
Enabling Reception of Directed Broadcasts to a Directly Connected Network·····························13-1
Enabling Forwarding of Directed Broadcasts to a Directly Connected Network···························13-2
Configuration Example··················································································································13-2
Configuring Cut-Through Forwarding ···································································································13-3
Enabling the SYN Cookie Feature········································································································13-3
Configuring TCP Attributes ···················································································································13-4
Configuring TCP Optional Parameters··························································································13-4
Configuring ICMP to Send Error Packets ·····························································································13-5
Displaying and Maintaining IP Performance Optimization····································································13-7
14 UDP Helper Configuration ····················································································································14-1
Introduction to UDP Helper···················································································································14-1
Configuring UDP Helper ·······················································································································14-1