C
HAPTER
25
| General Security Measures
DHCP Snooping
– 666 –
◆
When the DHCP snooping is globally disabled, DHCP snooping can still
be configured for specific VLANs, but the changes will not take effect
until DHCP snooping is globally re-enabled.
◆
When DHCP snooping is globally enabled, configuration changes for
specific VLANs have the following effects:
■
If DHCP snooping is disabled on a VLAN, all dynamic bindings
learned for this VLAN are removed from the binding table.
E
XAMPLE
This example enables DHCP snooping for VLAN 1.
Console(config)#ip dhcp snooping vlan 1
Console(config)#
R
ELATED
C
OMMANDS
ip dhcp snooping (661)
ip dhcp snooping trust (666)
ip dhcp snooping
trust
This command configures the specified interface as trusted. Use the
no
form to restore the default setting.
S
YNTAX
[
no
]
ip dhcp snooping trust
D
EFAULT
S
ETTING
All interfaces are untrusted
C
OMMAND
M
ODE
Interface Configuration (Ethernet, Port Channel)
C
OMMAND
U
SAGE
◆
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 ia enabled globally using the
ip dhcp snooping
command, and enabled on a VLAN with
ip dhcp snooping vlan
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.
Summary of Contents for ES3510MA
Page 1: ...Management Guide www edge core com 8 Port Layer 2 Fast Ethernet Switch...
Page 4: ...ABOUT THIS GUIDE 4...
Page 30: ...CONTENTS 30...
Page 40: ...FIGURES 40...
Page 46: ...TABLES 46...
Page 48: ...SECTION I Getting Started 48...
Page 72: ...SECTION II Web Configuration 72...
Page 88: ...CHAPTER 3 Using the Web Interface Navigating the Web Browser Interface 88...
Page 116: ...CHAPTER 4 Basic Management Tasks Resetting the System 116...
Page 154: ...CHAPTER 5 Interface Configuration VLAN Trunking 154...
Page 216: ...CHAPTER 8 Spanning Tree Algorithm Configuring Interface Settings for MSTP 216...
Page 350: ...CHAPTER 14 Security Measures DHCP Snooping 350...
Page 440: ...CHAPTER 17 IP Services Displaying the DNS Cache 440...
Page 484: ...CHAPTER 19 Using the Command Line Interface CLI Command Groups 484...
Page 554: ...CHAPTER 21 System Management Commands Switch Clustering 554...
Page 574: ...CHAPTER 22 SNMP Commands 574...
Page 582: ...CHAPTER 23 Remote Monitoring Commands 582...
Page 636: ...CHAPTER 24 Authentication Commands Management IP Filter 636...
Page 736: ...CHAPTER 29 Port Mirroring Commands RSPAN Mirroring Commands 736...
Page 816: ...CHAPTER 34 VLAN Commands Configuring Voice VLANs 816...
Page 830: ...CHAPTER 35 Class of Service Commands Priority Commands Layer 3 and 4 830...
Page 848: ...CHAPTER 36 Quality of Service Commands 848...
Page 900: ...CHAPTER 38 LLDP Commands 900...
Page 910: ...CHAPTER 39 Domain Name Service Commands 910...
Page 916: ...CHAPTER 40 DHCP Commands DHCP Client 916...
Page 948: ...CHAPTER 41 IP Interface Commands IPv6 Interface 948...
Page 950: ...SECTION IV Appendices 950...
Page 982: ...INDEX 982...
Page 983: ......