
Chapter 9
| General Security Measures
DHCPv4 Snooping
– 306 –
ip dhcp snooping
This command enables DHCP snooping globally. Use the
no
form to restore the
default setting.
Syntax
[
no
]
ip dhcp snooping
Default Setting
Disabled
Command Mode
Global Configuration
Command Usage
◆
Network traffic may be disrupted when malicious DHCP messages are received
from an outside source. DHCP snooping is used to filter DHCP messages
received on an unsecure interface from outside the network or fire wall. When
DHCP snooping is enabled globally by this command, and enabled on a VLAN
interface by the
command, DHCP messages received on
an untrusted interface (as specified by the
command) from a device not listed in the DHCP snooping table will be
dropped.
◆
When enabled, DHCP messages entering an untrusted interface are filtered
based upon dynamic entries learned via DHCP snooping.
◆
Table entries are only learned for trusted interfaces. Each entry includes a MAC
address, IP address, lease time, VLAN identifier, and port identifier.
ip dhcp snooping information
option circuit-id
Enables or disables the use of DHCP Option 82
information circuit-id suboption
IC
configures the maximum number of DHCP clients which
can be supported per interface
IC
Configures the specified interface as trusted
IC
clear ip dhcp snooping
binding
Clears DHCP snooping binding table entries from RAM
PE
clear ip dhcp snooping
database flash
Removes all dynamically learned snooping entries from
flash memory.
PE
ip dhcp snooping database
flash
Writes all dynamically learned snooping entries to flash
memory
PE
Shows the DHCP snooping configuration settings
PE
Shows the DHCP snooping binding table entries
PE
Table 58: DHCP Snooping Commands
(Continued)
Command
Function
Mode
Содержание ECS4120-28F
Страница 36: ...Contents 36...
Страница 38: ...Figures 38...
Страница 46: ...Section I Getting Started 46...
Страница 70: ...Chapter 1 Initial Switch Configuration Setting the System Clock 70...
Страница 86: ...Chapter 2 Using the Command Line Interface CLI Command Groups 86...
Страница 202: ...Chapter 5 SNMP Commands Additional Trap Commands 202...
Страница 210: ...Chapter 6 Remote Monitoring Commands 210...
Страница 216: ...Chapter 7 Flow Sampling Commands 216...
Страница 278: ...Chapter 8 Authentication Commands PPPoE Intermediate Agent 278...
Страница 360: ...Chapter 9 General Security Measures Port based Traffic Segmentation 360...
Страница 384: ...Chapter 10 Access Control Lists ACL Information 384...
Страница 424: ...Chapter 11 Interface Commands Power Savings 424...
Страница 446: ...Chapter 13 Power over Ethernet Commands 446...
Страница 456: ...Chapter 14 Port Mirroring Commands RSPAN Mirroring Commands 456...
Страница 488: ...Chapter 17 UniDirectional Link Detection Commands 488...
Страница 494: ...Chapter 18 Address Table Commands 494...
Страница 554: ...Chapter 20 ERPS Commands 554...
Страница 620: ...Chapter 22 Class of Service Commands Priority Commands Layer 3 and 4 620...
Страница 638: ...Chapter 23 Quality of Service Commands 638...
Страница 772: ...Chapter 25 LLDP Commands 772...
Страница 814: ...Chapter 26 CFM Commands Delay Measure Operations 814...
Страница 826: ...Chapter 27 OAM Commands 826 1 1 00 12 CF 6A 07 F6 000084 Enabled Disabled Enabled Disabled Console...
Страница 836: ...Chapter 28 Domain Name Service Commands 836...
Страница 848: ...Chapter 29 DHCP Commands DHCP Relay Option 82 848...
Страница 902: ...Section III Appendices 902...
Страница 916: ...Glossary 916...
Страница 926: ...CLI Commands 926...
Страница 937: ......
Страница 938: ...E092017 CS R02...