– 782 –
C
HAPTER
30
| General Security Measures
DHCP Snooping
◆
Use the
ip dhcp snooping information option
command to specify
how to handle DHCP client request packets which already contain
Option 82 information.
E
XAMPLE
This example enables the DHCP Snooping Information Option.
Console(config)#ip dhcp snooping information option
Console(config)#
ip dhcp snooping
information policy
This command sets the DHCP snooping information option policy for DHCP
client packets that include Option 82 information.
S
YNTAX
ip dhcp snooping information policy
{
drop
|
keep
|
replace
}
drop
- Drops the client’s request packet instead of relaying it.
keep
- Retains the Option 82 information in the client request, and
forwards the packets to trusted ports.
replace
- Replaces the Option 82 information circuit-id and
remote-id fields in the client’s request with information about the
relay agent itself, inserts the relay agent’s address (when DHCP
snooping is enabled), and forwards the packets to trusted ports.
D
EFAULT
S
ETTING
replace
C
OMMAND
M
ODE
Global Configuration
C
OMMAND
U
SAGE
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.
E
XAMPLE
Console(config)#ip dhcp snooping information policy drop
Console(config)#
Summary of Contents for LGB6026A
Page 6: ...ABOUT THIS GUIDE 4...
Page 40: ...38 CONTENTS...
Page 60: ...58 SECTION I Getting Started...
Page 86: ...84 SECTION II Web Configuration Unicast Routing on page 517 Multicast Routing on page 575...
Page 162: ...160 CHAPTER 5 Interface Configuration VLAN Trunking...
Page 196: ...194 CHAPTER 6 VLAN Configuration Configuring MAC based VLANs...
Page 204: ...CHAPTER 7 Address Table Settings Clearing the Dynamic Address Table 202...
Page 238: ...CHAPTER 11 Class of Service Layer 2 Queue Settings 236...
Page 254: ...252 CHAPTER 12 Quality of Service Attaching a Policy Map to a Port...
Page 448: ...446 CHAPTER 16 Multicast Filtering Multicast VLAN Registration...
Page 470: ...468 CHAPTER 17 IP Configuration Setting the Switch s IP Address IP Version 6...
Page 576: ...574 CHAPTER 21 Unicast Routing Configuring the Open Shortest Path First Protocol Version 2...
Page 606: ...604 CHAPTER 22 Multicast Routing Configuring PIMv6 for IPv6...
Page 620: ...618 CHAPTER 23 Using the Command Line Interface CLI Command Groups...
Page 672: ...670 CHAPTER 25 System Management Commands Time Range...
Page 692: ...690 CHAPTER 26 SNMP Commands...
Page 700: ...698 CHAPTER 27 Remote Monitoring Commands...
Page 854: ...CHAPTER 34 Port Mirroring Commands Local Port Mirroring Commands 852...
Page 862: ...860 CHAPTER 36 Address Table Commands...
Page 958: ...956 CHAPTER 40 Quality of Service Commands...
Page 1034: ...1032 CHAPTER 42 LLDP Commands...
Page 1044: ...1042 CHAPTER 43 Domain Name Service Commands...
Page 1062: ...1060 CHAPTER 44 DHCP Commands DHCP Server...
Page 1206: ...CHAPTER 47 IP Routing Commands Open Shortest Path First OSPFv3 1204...
Page 1250: ...1248 SECTION IV Appendices...
Page 1256: ...1254 APPENDIX A Software Specifications Management Information Bases...
Page 1278: ...1276 COMMAND LIST...