Web Management Guide-R06
Table Of Contents
- How to Use This Guide
- Contents
- Figures
- Tables
- Getting Started
- Web Configuration
- Using the Web Interface
- Basic Management Tasks
- Displaying System Information
- Displaying Hardware/Software Versions
- Configuring Support for Jumbo Frames
- Displaying Bridge Extension Capabilities
- Managing System Files
- Setting the System Clock
- Configuring the Console Port
- Configuring Telnet Settings
- Displaying CPU Utilization
- Displaying Memory Utilization
- Stacking
- Resetting the System
- Interface Configuration
- VLAN Configuration
- Address Table Settings
- Spanning Tree Algorithm
- Congestion Control
- Class of Service
- Quality of Service
- VoIP Traffic Configuration
- Security Measures
- AAA (Authentication, Authorization and Accounting)
- Configuring User Accounts
- Web Authentication
- Network Access (MAC Address Authentication)
- Configuring HTTPS
- Configuring the Secure Shell
- Access Control Lists
- Setting a Time Range
- Showing TCAM Utilization
- Setting the ACL Name and Type
- Configuring a Standard IPv4 ACL
- Configuring an Extended IPv4 ACL
- Configuring a Standard IPv6 ACL
- Configuring an Extended IPv6 ACL
- Configuring a MAC ACL
- Configuring an ARP ACL
- Binding a Port to an Access Control List
- Configuring ACL Mirroring
- Showing ACL Hardware Counters
- ARP Inspection
- Filtering IP Addresses for Management Access
- Configuring Port Security
- Configuring 802.1X Port Authentication
- DoS Protection
- IPv4 Source Guard
- IPv6 Source Guard
- DHCP Snooping
- Basic Administration Protocols
- Configuring Event Logging
- Link Layer Discovery Protocol
- Power over Ethernet
- Simple Network Management Protocol
- Configuring Global Settings for SNMP
- Setting the Local Engine ID
- Specifying a Remote Engine ID
- Setting SNMPv3 Views
- Configuring SNMPv3 Groups
- Setting Community Access Strings
- Configuring Local SNMPv3 Users
- Configuring Remote SNMPv3 Users
- Specifying Trap Managers
- Creating SNMP Notification Logs
- Showing SNMP Statistics
- Remote Monitoring
- Switch Clustering
- Ethernet Ring Protection Switching
- Connectivity Fault Management
- Configuring Global Settings for CFM
- Configuring Interfaces for CFM
- Configuring CFM Maintenance Domains
- Configuring CFM Maintenance Associations
- Configuring Maintenance End Points
- Configuring Remote Maintenance End Points
- Transmitting Link Trace Messages
- Transmitting Loop Back Messages
- Transmitting Delay-Measure Requests
- Displaying Local MEPs
- Displaying Details for Local MEPs
- Displaying Local MIPs
- Displaying Remote MEPs
- Displaying Details for Remote MEPs
- Displaying the Link Trace Cache
- Displaying Fault Notification Settings
- Displaying Continuity Check Errors
- OAM Configuration
- UDLD Configuration
- Multicast Filtering
- Overview
- Layer 2 IGMP (Snooping and Query for IPv4)
- Configuring IGMP Snooping and Query Parameters
- Specifying Static Interfaces for a Multicast Router
- Assigning Interfaces to Multicast Services
- Setting IGMP Snooping Status per Interface
- Filtering IGMP Query Packets and Multicast Data
- Displaying Multicast Groups Discovered by IGMP Snooping
- Displaying IGMP Snooping Statistics
- Filtering and Throttling IGMP Groups
- MLD Snooping (Snooping and Query for IPv6)
- Layer 3 IGMP (Query used with Multicast Routing)
- Multicast VLAN Registration for IPv4
- Multicast VLAN Registration for IPv6
- IP Configuration
- IP Services
- General IP Routing
- Configuring Router Redundancy
- Unicast Routing
- Overview
- Configuring the Routing Information Protocol
- Configuring General Protocol Settings
- Clearing Entries from the Routing Table
- Specifying Network Interfaces
- Specifying Passive Interfaces
- Specifying Static Neighbors
- Configuring Route Redistribution
- Specifying an Administrative Distance
- Configuring Network Interfaces for RIP
- Displaying RIP Interface Settings
- Displaying Peer Router Information
- Resetting RIP Statistics
- Configuring the Open Shortest Path First Protocol (Version 2)
- Defining Network Areas Based on Addresses
- Configuring General Protocol Settings
- Displaying Administrative Settings and Statistics
- Adding an NSSA or Stub
- Configuring NSSA Settings
- Configuring Stub Settings
- Displaying Information on NSSA and Stub Areas
- Configuring Area Ranges (Route Summarization for ABRs)
- Redistributing External Routes
- Configuring Summary Addresses (for External AS Routes)
- Configuring OSPF Interfaces
- Configuring Virtual Links
- Displaying Link State Database Information
- Displaying Information on Neighboring Routers
- Multicast Routing
- Appendices
- Glossary
- Index
Chapter 12
| Security Measures
DHCP Snooping
– 389 –
DHCP Snooping Option 82
◆ DHCP provides a relay mechanism for sending information about its DHCP
clients or the relay agent itself to the DHCP server. Also known as DHCP Option
82, it allows compatible DHCP servers to use the information when assigning IP
addresses, or to set other services or policies for clients. It is also an effective
tool in preventing malicious network attacks from attached clients on DHCP
services, such as IP Spoofing, Client Identifier Spoofing, MAC Address Spoofing,
and Address Exhaustion.
◆ DHCP Snooping must be enabled for Option 82 information to be inserted into
request packets.
◆ When the DHCP Snooping Information Option 82 is enabled, the requesting
client (or an intermediate relay agent that has used the information fields to
describe itself) can be identified in the DHCP request packets forwarded by the
switch and in reply packets sent back from the DHCP server. This information
may specify the MAC address or IP address of the requesting device (that is, the
switch in this context).
By default, the switch also fills in the Option 82 circuit-id field with information
indicating the local interface over which the switch received the DHCP client
request, including the port and VLAN ID. This allows DHCP client-server
exchange messages to be forwarded between the server and client without
having to flood them to the entire VLAN.
◆ If DHCP Snooping Information Option 82 is enabled on the switch, information
may be inserted into a DHCP request packet received over any VLAN
(depending on DHCP snooping filtering rules). The information inserted into
the relayed packets includes the circuit-id and remote-id, as well as the
gateway Internet address.
◆ When the switch receives DHCP packets from clients that already include DHCP
Option 82 information, the switch can be configured to set the action policy for
these packets. The switch can either drop the DHCP packets, keep the existing
information, or replace it with the switch’s relay information.
DHCP Snooping
Global Configuration
Use the IP Service > DHCP > Snooping (Configure Global) page to enable DHCP
Snooping globally on the switch, or to configure MAC Address Verification.
Parameters
These parameters are displayed:
General
◆ DHCP Snooping Status – Enables DHCP snooping globally. (Default: Disabled)
◆ DHCP Snooping MAC-Address Verification – Enables or disables MAC
address verification. If the source MAC address in the Ethernet header of the