BOOTP/DHCP option 82, Relay Agent Information

Description Glossary RFCs Publications Obsolete RFCs


Protocol suite: TCP/IP.
Protocol type:Application layer configuration protocol.
Option length:Variable.
Links:IANA: BOOTP and DHCP options.

This option is inserted by the DHCP relay agent when forwarding client-originated DHCP packets to a DHCP server. Servers recognizing the Relay Agent Information option may use the information to implement IP address or other parameter assignment policies. The DHCP Server echoes the option back verbatim to the relay agent in server-to-client replies, and the relay agent strips the option before forwarding the reply to the client.

The option may contain one or more sub-options that convey information known by the relay agent.

MAC header IP header UDP header BOOTP | DHCP header BOOTP/DHCP option Data :::

BOOTP/DHCP option 82:

0001020304050607 0809101112131415 1617181920212223 2425262728293031
Code Length Data :::

Code. 8 bits. Always set to 82.
Option code.

Length. 8 bits.
Size of the option data in bytes.

Data. Variable length.
Contains the suboptions for this option.

0001020304050607 0809101112131415 1617181920212223 2425262728293031
Suboption Suboption length Suboption data :::

Suboption. 8 bits.

SuboptionSuboption lengthDescriptionReferences
1 Agent Circuit ID.RFC 3046
2 Agent Remote ID.RFC 3046
4 DOCSIS Device Class.RFC 3256
5 Link selection.RFC 3527
6 Subscriber-ID.RFC 3993
7 RADIUS attributes.RFC 4014
8 Authentication.RFC 4030
9 Vendor-Specific Information.RFC 4243
10 Relay Agent Flags.RFC 5010
11 Server Identifier Override.RFC 5107
1511+DHCPv4 Virtual Subnet Selection. RFC 6607
1520DHCPv4 Virtual Subnet Selection Control. RFC 6607

Suboption length. 8 bits.
Length of the suboption data in bytes.

Suboption data. Variable length.
Data contained within the suboption.



[RFC 3046] DHCP Relay Agent Information Option.

[RFC 4243] Vendor-Specific Information Suboption for the Dynamic Host Configuration Protocol (DHCP) Relay Agent Option.

[RFC 6607] Virtual Subnet Selection Options for DHCPv4 and DHCPv6.


Obsolete RFCs:

Description Glossary RFCs Publications Obsolete RFCs