
Chapter 29
| DHCP Commands
DHCP Relay Option 82
– 843 –
ip dhcp relay
information option
This command enables DHCP Option 82 information relay, and specifies the frame
format to use for the remote-id when Option 82 information is generated by the
switch. Use the
no
form of this command to disable this feature.
Syntax
ip dhcp relay information option
[
encode no-subtype
]
[
vlan
vlan-list
|
add
vlan-list
|
remove
vlan-list
]
no
ip dhcp rely information option
[
encode no-subtype
]
encode no-subtype - Disables use of sub-type and sub-length fields in circuit-
ID (CID) and remote-ID (RID) in Option 82 information.
vlan
vlan-list
- Enables DHCP Option 82 information relay for the specified
VLAN or list of VLANs. Separate nonconsecutive VLANs with a comma and
no spaces; or use a hyphen to designate a range of VLANs. (Range: 1-4094)
add
vlan-list
- Enables DHCP Option 82 information relay for the specified
VLANs to an existing list of Option 82 enabled VLANs.
remove
vlan-list
- Disables DHCP Option 82 information relay for the
specified VLANs within an existing list of Option 82 enabled VLANs
Default Setting
Option 82: Disabled
CID/RID sub-type: Enabled
Command Mode
Global Configuration
Usage Guidelines
◆
Using this command with or without any keywords will enable DHCP Option 82
information relay. You must also specify the IP address for at least one active
DHCP server (with the
command). Otherwise, the switch’s
DHCP relay agent will not be able to forward client requests to a DHCP server.
◆
DHCP provides a relay agent information option 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 this information
when assigning IP addresses, or to set other services or policies for clients.
◆
When 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.
◆
By default, the relay agent 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 VLAN ID, stack unit, and port. This allows
DHCP client-server exchange messages to be forwarded between the server
and client without having to flood them onto the entire VLAN.
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...
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Страница 938: ...E092017 CS R02...