RADIUS Attributes Permitted in RADIUS Attributes DHCP Suboption

The RADIUS Attributes suboption () enables a network element to pass identification and authorization attributes received during RADIUS authentication to a DHCP server . However, defines a frozen set of RADIUS attributes that can be included in such a suboption. This limitation is suboptimal in contexts where new services are deployed (e.g., support of encrypted DNS ). updates RFC 4014 by relaxing that constraint and allowing to tag additional RADIUS Attributes as permitted in the RADIUS Attributes DHCP suboption. To that aim, a new IANA registry is created to maintain the set of permitted attributes in the RADIUS Attributes DHCP suboption. The maintenance of such a registry is similar to the one in . defines the DHCPv4-Options RADIUS attribute that can be used by a DHCP relay agent, collocated with a RADIUS client, to pass attributes obtained from a RADIUS server to a DHCP server. The DHCPv4-Options RADIUS attribute can, for example, include a list of encrypted DNS resolvers.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

This document updates Section 3 of as follows: To avoid dependencies between the address allocation and other state information between the RADIUS server and the DHCP server, the DHCP relay agent SHOULD include only the attributes in the table below in an instance of the RADIUS Attributes suboption. The table, based on the analysis in RFC 3580 [8], lists attributes that MAY be included:

To avoid dependencies between the address allocation and other state information between the RADIUS server and the DHCP server, the DHCP relay agent SHOULD include only the attributes in the IANA-maintained registry () in an instance of the RADIUS Attributes suboption.

This document updates Section 4 of as follows: If the relay agent relays RADIUS attributes not included in the table in Section 4, the DHCP server SHOULD ignore them. If the relay agent relays RADIUS attributes not included in the IANA-maintained registry (), the DHCP server SHOULD ignore them.

IANA is requested to create a new sub-registry entitled "RADIUS Attributes Permitted in RADIUS Attributes Sub-option" in the "Dynamic Host Configuration Protocol (DHCP) and Bootstrap Protocol (BOOTP) Parameters" registry . The allocation policy of this new sub-registry is Expert Review per . Designated experts should carefully consider the security implications of allowing the relay agent to include new RADIUS attributes to this registry. The initial content of this sub-registry is listed in . Type Code Attribute Reference 1 User-Name RFC 2865 6 Service-Type RFC 2865 26 Vendor-Specific RFC 2865 27 Session-Timeout RFC 2865 88 Framed-Pool RFC 2869 100 Framed-IPv6-Pool RFC 3162 245.TBA1 DHCPv4-Options This-Document

This document does not add new security considerations to those already discussed in Section 7 of .

To be completed.