Function
This command is used to enable or disable the DHCP option82 feature of the
service virtual port. The DHCP feature does not have any mechanism for
authentication or security. Thus, the DHCP feature encounters many security
problems when it is used in the network. To solve these problems, the DHCP
option82 is introduced. After the DHCP option82 feature is enabled, the BRAS can
authenticate IDs of access users. After the DHCP option82 feature is disabled,
the device only transparently transmits DHCP packets and does not process
packets.
Format
dhcp option82 service-port { service-portid |
frameid/slotid/portid { stream | { user-vlan
{ untagged | priority-tagged |
user-vlanid } [ user-encap user-encap ] |
user-encap user-encap | user-8021p
user-8021p [ user-vlan user-vlanid ] } } } {
enable | disable }
dhcp option82 service-port frameid/slotid/portid { vpi vpi vci vci [ user-vlan { untagged | priority-tagged | user-vlanid } [ user-encap user-encap ] | user-encap user-encap | user-8021p user-8021p [ user-vlan user-vlanid ] ] | autosense } { enable | disable }
dhcp option82 service-port frameid/slotid/portid gemport gemport-id { stream | { user-vlan { untagged | priority-tagged | user-vlanid } [ user-encap user-encap ] | user-encap user-encap | user-8021p user-8021p [ user-vlan user-vlanid ] } } { enable | disable }
dhcp option82 service-port frameid/slotid/portid { vpi vpi vci vci [ user-vlan { untagged | priority-tagged | user-vlanid } [ user-encap user-encap ] | user-encap user-encap | user-8021p user-8021p [ user-vlan user-vlanid ] ] | autosense } { enable | disable }
dhcp option82 service-port frameid/slotid/portid gemport gemport-id { stream | { user-vlan { untagged | priority-tagged | user-vlanid } [ user-encap user-encap ] | user-encap user-encap | user-8021p user-8021p [ user-vlan user-vlanid ] } } { enable | disable }
Parameters
| Parameter | Description | Value |
|---|---|---|
| service-portid | Indicates the service virtual port. When you need to enable or disable the DHCP option82 feature of the specified service virtual port, use this parameter. | |
| frameid/slotid/portid | Indicates the subrack ID, slot ID, and port ID. Enter a slash (/) between the subrack, slot, and port IDs. When you need to enable or disable the DHCP option82 feature of the specified physical port on a board, use this parameter. | Please see Differences Between Shelves. |
| user-vlan | Indicate that when the users of the service virtual port are differentiated based on the user-side VLAN, this parameter is used. | - |
| untagged | Indicates that when the service virtual port needs to carry multiple services and the services are differentiated by the user-side VLAN, you can specify the packet type as untagged. | - |
| priority-tagged | Indicates that users are differentiated by the priority-tagged. When the user-side packets are tagged and this VLAN tag is 0, use this keyword. | - |
| user-vlanid | Indicates the VLAN ID. It identifies a VLAN uniquely. | Numeral type. Range: 1-4095. |
| user-encap user-encap |
Indicates the user-side encapsulation type. When the users of the
service virtual port are differentiated based on the user-side encapsulation
type, use this parameter.
|
Enumerated type. Options: ipoe and pppoe. |
| user-8021p user-8021p | Indicates the user-side priority. When the users of the service virtual port are differentiated based on the user-side priority, use this parameter. | Numeral type. Range: 0-7. |
| vpi vpi | Indicates the VPI value to be entered. It is used to identify a user when used with the VCI. |
Numeral type. Range:
|
| vci vci | Indicates the VCI value to be entered. It is used to identify a user when used with the VPI. |
|
| gemport gemport-id | Indicates the GEM port ID. | Numeral type. Range: 128-3999. |
| stream | Indicates the single traffic stream with the Ethernet access type. | - |
| autosense | Indicates the auto-sensing service virtual port. When the corresponding service virtual port needs to automatically learn user-side VPI/VCI, use this keyword. | - |
| enable | Indicates that the DHCP Option82 feature is enabled. Option 82 is an option of the DHCP packet. Its code is 82, which is used to identify the user. After the feature is enabled, the DHCP server can allocate IP addresses for users based on this DHCP Option82 option and avoid the spoofing attacks to the DHCP server, such as the DHCP IP exhaustion. | - |
| disable | Indicates that the DHCP Option82 feature is disabled. Option 82 is an option of the DHCP packet. Its code is 82, which is used to identify the user. After the feature is disabled, the DHCP server does not perform the Option82 processing for packets. | - |
Usage Guidelines
- By default, the DHCP option82 feature of the service virtual port is enabled.
- By default, the global DHCP option82 is disabled while the DHCP option82 feature of a port is enabled. If the global DHCP option82 is disabled, even if the DHCP option82 feature of a port is enabled, the DHCP option82 feature of the port is disabled. No vendor tag is added to the DHCP packets sent from the port. Only when the DHCP option82 feature is enabled globally and on a port, vendor tags are added to the DHCP packets sent from the port.
- For connection-orientied service ports, if the network role of a port is not user, the DHCP Option82 feature does not take effect for the port. Specifically, vendor tag information is not added to DHCP packets received from the port regardless of whether the DHCP Option82 feature is enabled or disabled for the port.
Example
To disable the DHCP option82 feature of the service virtual port with VPI/VCI
of 0/35 at ADSL port 0/3/0, do as follows:
huawei(config)#dhcp option82 service-port
{ frameid/slotid/portid<S><Length 5-18>|integer<U><0,32767> }:0/3/0
{ autosense<K>|gemport<K>|stream<K>|user-8021p<K>|user-encap<K>|user-vlan<K>|vpi<K> }:vpi
{ vpi<U><0,4095> }:0
{ vci<K> }:vci
{ vci<U><32,65535> }:35
{ disable<K>|enable<K>|user-8021p<K>|user-encap<K>|user-vlan<K> }:disable
Command:
dhcp option82 service-port 0/3/0vpi 0 vci 35 disable
To enable the DHCP option82 feature of the service virtual port with GEM port
ID of 128 at GPON port 0/3/0, do as follows:huawei(config)#dhcp option82 service-port
{ frameid/slotid/portid<S><Length 5-18>|integer<U><0,32767> }:0/3/0
{ autosense<K>|gemport<K>|stream<K>|user-8021p<K>|user-encap<K>|user-vlan<K>|vpi<K> }:gemport
{ integer<U><128,3999> }:128
{ stream<K>|user-8021p<K>|user-encap<K>|user-vlan<K> }:stream
{ disable<K>|enable<K> }:enable
Command:
dhcp option82 service-port 0/3/0 gemport 128 stream enable
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