RFC 3679

Unused Dynamic Host Configuration Protocol (DHCP) Option Codes

📅 published January 2004, from ietf

RFC 3679 🎀 (Part 1 of 2!) is titled Unused Dynamic Host Configuration Protocol (DHCP) Option Codes ✨. Ralph Droms wrote it at Cisco Systems, it's dated January 2004, and its category is Informational 🌸. Informational means it gives the Internet community info, and it does not specify an Internet standard. The header has no Obsoletes or Updates line, but the Abstract does mention RFC 2489 and RFC 2939, so keep an eye on that. 👀

Status of This Memo

This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. 📜

Copyright (C) The Internet Society (2004). All Rights Reserved. ©️

Abstract

Okay so, before RFC 2489 came out (and RFC 2939 later updated it), a bunch of option codes got assigned to DHCP options that were proposed but never actually used. 😭 This doc lists those unused codes and tells IANA to make them available for future DHCP options. It also lists some codes that aren't documented in any RFC yet but should not be handed out to future DHCP options, because they're still in play. 🧚

1. Introduction 🌷

Section 2 lists the unused DHCP option codes from the IANA list of BOOTP and DHCP option codes [1]. Each code comes with any known documentation and contact info from that IANA list. IANA will make these codes available for assignment to other DHCP options in the future. 💖

Section 3 lists several DHCP option codes that aren't documented in an RFC yet, but should not be made available for reassignment to future DHCP options. 🫶

2. Unused DHCP Option Codes to be Reassigned to Future DHCP Options 💅

The codes in this section are going back to IANA so they can be reassigned to new options. Where contact people have responded, those responses are noted. ✨

2.1. Service Location Protocol Naming Authority

Code:              80
Name:              Service Location Protocol Naming Authority
Defined in:        (expired Internet-Draft)
Contact:           Charlie Perkins
Reason to recover: Never published as standard and not in general use

2.2. Relay Agent Options

Codes:             83, 84
Name:              Relay Agent Options
Defined in:        Early draft of RFC 3046 [2]
Contact:           (none)
Reason to recover: Not defined in RFC 3046 as published

2.3. IEEE 1003.1 POSIX Timezone

Code:              88
Name:              IEEE 1003.1 POSIX Timezone
Defined in:        (expired Internet-Draft)
Contact:           Mike Carney
Reason to recover: Never published as standard and not in general use

2.4. FQDNs in DHCP Options

Code:              89
Name:              FQDNs in DHCP Options
Defined in:        (expired Internet-Draft)
Contact:           Ralph Droms; agrees that option code should be
                   reassigned
Reason to recover: Never published as standard and not in general use

2.5. VINES TCP/IP Server

Code:              91
Name:              VINES TCP/IP Server
Defined in:        (none)
Contact:           (none)
Reason to recover: Never published as Internet-Draft

2.6. Server Selection

Code:              92
Name:              Server Selection
Defined in:        (none)
Contact:           (none)
Reason to recover: Never published as Internet-Draft

2.7 IPv6 Transition

Code:              96
Name:              IPv6 Transition
Defined in:        (expired Internet-Draft)
Contact:           Dan Harrington; agrees that option code should be
                   reassigned
Reason to recover: Never published as standard and not in general use

2.8. Printer Name

Code:              100
Name:              Printer Name
Defined in:        (none)
Contact:           (none)
Reason to recover: Never published as Internet-Draft

2.9. Multicast Assignment through DHCP

Code:              101
Name:              Multicast Assignment through DHCP
Defined in:        (expired Internet-Draft)
Contact:           Baiju Patel, Munil Shah
Reason to recover: Never published as standard and not in general use

2.10. Swap Path

Code:              108
Name:              Swap Path
Defined in:        (none)
Contact:           (none)
Reason to recover: Never published as Internet-Draft

2.11. IPX Compatibility

Code:              110
Name:              IPX Compatibility
Defined in:        (none)
Contact:           Juan Luciani; agrees that option code should be
                   reassigned
Reason to recover: Never published as Internet-Draft

2.12. Failover

Code:              115
Name:              Failover
Defined in:        Early revisions of "DHCP Failover Protocol" [3]
Contact:           Kim Kinnear
Reason to recover: Current version of "DHCP Failover Protocol" does
                   not use a DHCP option

3. Option codes to be reserved by IANA 🔒

These codes are part of ongoing work in the DHC Working Group (WG). They should stay on the IANA list of assigned option codes [1] until the DHC WG has made a final decision about what happens to them. 🧐

3.1. Option codes used in PXE Specification

The following option codes are used in the "Preboot Execution Environment (PXE) Specification, Version 2.1" [4]. Although these options are in widespread use by devices that use PXE, none of these option codes have been described in a published RFC. 🤔

The DHC WG will endeavor to have specifications for these options published. 🙏

3.1.1. Client System

Code:              93
Name:              Client System
Defined in:        "Preboot Execution Environment (PXE)
                   Specification, Version 2.1" [4]
Contact:           Michael Johnston
                   (frenchy@quiet-like-a-panther.org)

3.1.2. Client NDI

Code:              94
Name:              Client NDI
Defined in:        "Preboot Execution Environment (PXE)
                   Specification, Version 2.1" [4]
Contact:           Michael Johnston
                   (frenchy@quiet-like-a-panther.org)

3.1.3. UUID/GUID Client Identifier

Code:              97
Name:              UUID/GUID Client Identifier
Defined in:        "Preboot Execution Environment (PXE)
                   Specification, Version 2.1" [4] (and an expired
                   Internet-Draft)
Contact:           Dan Harrington, Michael Johnston
                   (frenchy@quiet-like-a-panther.org)

3.2. In Use by Apple 🍎

The following option codes are used by devices from Apple Computer. However, none of these option codes have been described in a published RFC. 🫠

The DHC WG will endeavor to have specifications for these options published. 🙏

3.2.1. LDAP Servers

Code:              95
Name:              LDAP Servers
Defined in:        (none)
Contact:           Dieter Siegmund, dieter@apple.com
Reason to recover: Never published in an RFC

3.2.2. Netinfo Parameters

Codes:             112, 113
Name:              Netinfo Address, Netinfo Tag
Defined in:        (none)
Contact:           Dieter Siegmund, dieter@apple.com
Reason to recover: Never published in an RFC

3.2.3. URL

Code:              114
Name:              URL
Defined in:        (none)
Contact:           Dieter Siegmund, dieter@apple.com
Reason to recover: Never published in an RFC

3.3. Option Code Extensions 🧩

Note that these option codes are identified in "Extending DHCP Options Codes" [5] as part of a mechanism for extending the set of option codes available to DHCP. If these option codes are not used for DHCP option code extension, they will be returned to IANA for reassignment to other DHCP options. 🔁

Codes:             126, 127
Name:              Option Code Extensions
Defined in:        (expired Internet-Draft)
Contact:           Ralph Droms
Part 2 is next! It covers Section 4 (Already Returned for Reassignment), the Security Considerations, the IANA Considerations, the References, the Intellectual Property Statement, and the Author's Address. 🦋

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