DHCP server commands

dhcp

Syntax

dhcp

Context

config>service>vprn>if

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

Commands in this context configure DHCP parameters.

action

Syntax

action {replace | drop | keep}

no action

Context

config>service>vprn>if>dhcp>option

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command configures the processing required when the router receives a DHCP request that already has a Relay Agent Information Option (Option 82) field in the packet.

The no form of this command reverts to the default value.

In accordance with RFC 3046, DHCP Relay Agent Information Option, section 2.1.1, Reforwarded DHCP Requests, the default is to keep the existing information intact. The exception to this is if the GIADDR of the received packet is the same as the ingress address on the router. In this case, the packet is dropped and an error is logged.

Parameters

replace

Keyword that specifies that, in the upstream direction (from the user), the existing Option 82 field is replaced with the Option 82 field from the router. In the downstream direction (toward the user) the Option 82 field is stripped (in accordance with RFC 3046).

drop

Keyword that specifies the packet is dropped, and an error is logged.

keep

Keyword that specifies the existing information is kept in the packet and the router does not add any additional information. In the downstream direction the Option 82 field is not stripped and is sent on toward the client.

The behavior is slightly different in case of Vendor Specific Options (VSOs). When the keep parameter is specified, the router inserts its own VSO into the Option 82 field. This occurs only when the incoming message already has an Option 82 field.

If no Option 82 field is present, the router does not create the Option 82 field. In this case, no VSO is added to the message.

circuit-id

Syntax

circuit-id [ascii-tuple | ifindex | sap-id | vlan-ascii-tuple]

no circuit-id

Context

config>service>vprn>if>dhcp>option

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

When enabled, the router sends the interface index (If Index) in the circuit-id suboption of the DHCP packet. Display the If Index of a router interface using the show router interface detail command. This option specifies data that must be unique to the router that is relaying the circuit.

If disabled, the circuit-id suboption of the DHCP packet is left empty.

The no form of this command reverts to the default value.

Default

circuit-id

Parameters

ascii-tuple

Keyword to specify that the ASCII-encoded concatenated tuple will be used, which consists of the access-node-identifier, service-id, and interface-name, separated by ‟|”.

ifindex

Keyword to specify that the interface index is used. Display the If Index of a router interface using the show router interface detail command.

sap-id

Keyword to specify that the SAP ID is used.

vlan-ascii-tuple

Keyword to specify that the format included VLAN ID and dot1p bits in addition to what is already included in the ascii-tuple. The format is supported on dot1q and qinq ports only. Therefore, when the Option 82 bits are stripped, dot1p bits are copied to the Ethernet header of an outgoing packet.

gi-address

Syntax

gi-address ip-address [src-ip-addr]

no gi-address

Context

config>service>vprn>if>dhcp

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command configures the gateway IP address (GIADDR) for the DHCP relay. A subscriber interface can include multiple group interfaces with multiple SAPs. The GIADDR is needed when the router functions as a DHCP relay to distinguish between the different subscriber interfaces and potentially between the group interfaces defined.

Default

no gi-address

Parameters

ip-address

Specifies the host IP address to be used for DHCP relay packets.

src-ip-address

Specifies the source IP address to be used for DHCP relay packets.

option

Syntax

[no] option

Context

config>service>vprn>if>dhcp

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command enables DHCP Option 82 (Relay Agent Information Option) parameter processing and enters the context for configuring Option 82 suboptions.

The no form of this command reverts to the default value.

Default

no option

remote-id

Syntax

remote-id [mac | string string]

no remote-id

Context

config>service>vprn>sub-if>grp-if>dhcp>option

config>service>vprn>nw-if>dhcp>option

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

When enabled, the router sends the MAC address of the remote end (typically the DHCP client) in the remote-id suboption of the DHCP packet. This command identifies the host at the other end of the circuit. If disabled, the remote-id suboption of the DHCP packet will be left empty.

The no form of this command reverts to the default value.

Default

remote-id

Parameters

mac

Keyword that specifies the MAC address of the remote end is encoded in the suboption.

string string

Specifies the remote ID.

vendor-specific-option

Syntax

[no] vendor-specific-option

Context

config>service>vprn>if>dhcp>option

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command configures the Nokia vendor-specific suboption of the DHCP relay packet.

client-mac-address

Syntax

[no] client-mac-address

Context

config>service>vprn>if>dhcp>option>vendor

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command enables the sending of the MAC address in the vendor-specific suboption of the DHCP relay packet.

The no form of this command disables the sending of the MAC address in the vendor-specific suboption of the DHCP relay packet.

pool-name

Syntax

[no] pool-name

Context

config>service>vprn>if>dhcp>option>vendor

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command sends the pool name in the vendor-specific suboption of the DHCP relay packet.

The no form of this command disables the sending.

sap-id

Syntax

[no] sap-id

Context

config>service>vprn>if>dhcp>option>vendor

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command enables the sending of the SAP ID in the vendor-specific suboption of the DHCP relay packet.

The no form of this command disables the sending of the SAP ID in the vendor-specific suboption of the DHCP relay packet.

service-id

Syntax

[no] service-id

Context

config>service>vprn>if>dhcp>option>vendor

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command enables the sending of the service ID in the vendor-specific suboption of the DHCP relay packet.

The no form of this command disables the sending of the service ID in the vendor-specific suboption of the DHCP relay packet.

string

Syntax

[no] string text

Context

config>service>vprn>if>dhcp>option>vendor

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command specifies the vendor-specific suboption string of the DHCP relay packet.

The no form of this command reverts to the default value.

Parameters

text

Specifies a string of any combination of ASCII characters, up to 32 characters. If spaces are used in the string, enclose the entire string in quotation marks (‟ ”).

system-id

Syntax

[no] system-id

Context

config>service>vprn>if>dhcp>option>vendor

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command specifies whether the system ID is encoded in the vendor-specific suboption of Option 82.

server

Syntax

server server1 [server2...(up to 8 max)]

Context

config>service>vprn>if>dhcp

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command specifies a list of servers where requests will be forwarded. The list of servers can be entered as IP addresses or fully qualified domain names. There must be at least one server specified for DHCP relay to work. If there are multiple servers, the request is forwarded to all the servers in the list. There can be a maximum of 8 DHCP servers configured.

The flood command is applicable only in the VPLS case. There is a scenario with VPLS where the VPLS node only needs to add Option 82 information to the DHCP request to provider per-subscriber information, but it does not do full DHCP relay. In this case, the server is set to "flood". This means the DHCP request is still a broadcast and is sent through the VPLS domain. A node running at L3 further upstream can then perform the full L3 DHCP relay function.

Default

no server

Parameters

server

Specifies the DHCP server IP address.

trusted

Syntax

[no] trusted

Context

config>service>vprn>if>dhcp

Platforms

7210 SAS-K 2F6C4T and 7210 SAS-K 3SFP+ 8C

Description

This command, if enabled on an IP interface, specifies that the relay agent (the SR-Series) will modify the request GIADDR to be equal to the ingress interface and forward the request. According to RFC 3046, DHCP Relay Agent Information Option, a DHCP request where the GIADDR is 0.0.0.0 and that contains an Option 82 field in the packet, should be discarded, unless it arrives on a "trusted" circuit.

This behavior applies only when the action in the Relay Agent Information Option is "keep". In the case where the Option 82 field is being replaced by the relay agent (action = "replace"), the original Option 82 information is lost, therefore there is no reason to enable the trusted command.

The no form of this command reverts to the default value.

Default

not enabled