
Chapter 9
| General Security Measures
DHCPv4 Snooping
– 318 –
Command Usage
◆
A trusted interface is an interface that is configured to receive only messages
from within the network. An untrusted interface is an interface that is
configured to receive messages from outside the network or fire wall.
◆
Set all ports connected to DHCP servers within the local network or fire wall to
trusted, and all other ports outside the local network or fire wall to untrusted.
◆
When DHCP snooping is enabled globally using the
command, and enabled on a VLAN with
command,
DHCP packet filtering will be performed on any untrusted ports within the
VLAN according to the default status, or as specifically configured for an
interface with the
no ip dhcp snooping trust
command.
◆
When an untrusted port is changed to a trusted port, all the dynamic DHCP
snooping bindings associated with this port are removed.
◆
Additional considerations when the switch itself is a DHCP client
– The port(s)
through which it submits a client request to the DHCP server must be
configured as trusted.
Example
This example sets port 5 to untrusted.
Console(config)#interface ethernet 1/5
Console(config-if)#no ip dhcp snooping trust
Console(config-if)#
Related Commands
ip dhcp snooping (306)
ip dhcp snooping vlan (314)
clear ip dhcp
snooping binding
This command clears DHCP snooping binding table entries from RAM. Use this
command without any optional keywords to clear all entries from the binding
table.
Syntax
clear ip dhcp snooping binding
[
mac-address
vlan
vlan-id
]
mac-address
- Specifies a MAC address entry.
(Format: xx-xx-xx-xx-xx-xx)
vlan-id
- ID of a configured VLAN (Range: 1-4094)
Command Mode
Privileged Exec
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...