Network Working Group                            Philip J. Nesser II
draft-ietf-2000-issue-01.txt              Nesser & Nesser Consulting
Internet Draft                                         November 1997

        The Internet and the Millenium Problem (Year 2000)

Status of this Memo

   This document is an Internet Draft. Internet Drafts are working
   documents of the Internet Engineering Task Force (IETF), its Areas,
   and its Working Groups. Note that other groups may also distribute
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   Please check the I-D abstract listing contained in each Internet
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The Year 2000 Working Group(WG) has conducted an investigation into
the millenium problem as it regards Internet related protocols.
This investigation only targeted the protocols as documented in the
Request For Comments Series (RFCs).  This investigation discovered
little reason for concern with regards to the functionality of the
protocols.  A few minor cases of older implementations still using
two digit years (ala RFC 850) were discovered, but almost all
Internet protocols were given a clean bill of health.  Several cases
of "period" problems were discussed where a time field would "roll
over" as the size of field was reached.  In particular, there are
several protocols, which have 32 bit, signed integer representations
of the number of seconds since January 1, 1970 which will turn
negative at Tue Jan 19 03:14:07 GMT 2038.  Areas whose protocols
will be effected by such problems have been notified so that new
revisions will remove this limitation.

1.0 Introduction

According to the trade press billions of dollars will be spend the
upcoming three years on the year 2000 problem, also called the
millenium problem (though the third millenium will only start in
2001). This problem consists of the fact that many software packages
and some protocols use a two-digit field for the year in a date
field. Most of the problems seem to be in administrative and
financial programs, or in the hardcoded microcomputers found in
electronic equipment.  A lot of organizations are now starting to
make an inventory of which software and tools they use will suffer
from the millenium problem.

With the increasing popularity of the Internet, more and more
organizations start to use the Internet as a serious business tool.
This means that most organizations will want to analyze the millenium
problems due to the use of Internet protocols and popular Internet
software. In the trade press the first articles suggest that the
Internet will collapse at midnight the 31st of December 1999.

To counter these suggestions (that are obviously wrong) and to avoid
that all over the Internet people will redo the same inventory over and
over again the WG is to make an inventory of all important Internet
protocols and their most popular implementations with respect to the
millenium problem. Only software and protocols directly related to the
Internet will be considered.

The editor of this document would like to acknowledge the critical
contributions of the follow for direct performance of research and the
provision of text: Alex Latzko, Robert Elz, Erik Huizer, Gillian
Greenwood, Barbara Jennings, R.E. (Robert) Moore, David Mills, Lynn
Kubinec, Chris Newman, Erik-Jan Bos, Paul Hoffman, and Rick H. Wesson.
The pace with which this group has operated has only been achievable by
the intimate familiarity of the contributors with the protocols and
ready access to the collective knowledge of the IETF.


This RFC is not complete.  It is an effort to analyze the Y2K impact on
hundreds of protocols but is likely to have missed some protocols and
misunderstood others.  Organizations should not attempt to claim any
legitimacy or approval for any particular protocol based on this
document.  The efforts have concentrated on the identification of
potential problems, rather than solutions to any of the problems that
have been identified. Any proposed solutions are only that: proposed.
A formal engineering review should take place before any solution is

<<Editor's Note:  A draft of this disclaimer has been forwarded to the
ISOC lawyers for review and (most likely) rewrite.>>


The first task was dividing the types of RFC's into logical groups
rather than the strict numeric publishing order.  Fifteen specific
areas were identified.  They are: "Autoconfiguration" , "Directory
Services", "Disk Sharing", "Games and Chat" ,"Information Services &
File Transfer", "Network & Transport Layer", "Electronic Mail", "NTP",
Name Serving", "Network Management", "News", "Real Time Services",
"Routing", "Security", and "Virtual Terminal".  In addition to these
categories many hundreds of RFC's were immediately eliminated because
of the type of content.  That is not to say that all Informational
RFC's were not considered, many did contain some technical content or
overview which demanded scrutiny.

Each area was assigned to a team for investigation.  Although each team
used whatever additional investigation techniques which seemed
appropriate (including completely reading each RFC, and in some cases
the source code for the reference implementation) at minimum each team
used an automatic scanning system to search for the following items
(case insensitively) in each RFC:

     - date
     - GMT
     - UTCTime
     - year
     - yy (that is not part of yyyy)
     - two-digit, 2-digit, 2digit
     - century
     - 1900 & 2000

Note that all of these strings except "UTCTime" may occur in
conjunction with a date format that accommodates the Year 2000
crossing, as well as with one that does not.  So "hits" on these string
do not necessarily indicate Year 2000 problems: they simply identify
elements that need to be examined.

After the documents were scanned, therefore, each "hit" was examined
individually.  Those that cause no Year 2000 problems (e.g., those that
encode the year as a two-byte integer, or as a four-character display
string) are not discussed here.  Those that do cause Year 2000 problems
are identified in this document, and the nature and impact of the
problems they cause are described.

Types of Year 2000 Problems

Summary of Solutions

2.0 Autoconfiguration


The RFC's which were categorized into this group were primarily the
BOOT Protocol (BOOTP) and the Dynamic Host Configuration Protocol
(DHCP) for both IP version four and six.

Examination of the BOOTP protocols and most popular implementations
show no year 2000 problems.  All times are references as 32 bit
integers in seconds of UTC time.

<< EDITOR'S NOTE:  We still need DHCP investigation.>>


3.0 Directory Services


The RFC's which were categorized into this group were primarily X.500
related RFC's, Whois, Rwhois, Whois++, and the Lightweight Directory
Access Protocol (LDAP).

Upon review of the Directory Services related RFC's, no serious year
2000 problems were discovered.  Some minor issues were noted and
explained below in the specifics portion of this section.


RFCs that mentioned UTC Time or made reference to uTCTimeSyntax could
fail to be Y2K compliant. These should be updated to specify the
four year version of uTCTimeSyntax rather than giving the option of
using a two year date representation. The following RFCs fall into this

    rfc1274.txt - References UTC date/time
    rfc1276.txt - References UTC date/time for version control.
    rfc1488.txt - References UTC Time as printable strings.
    rfc1608.txt - Refers to uTCTimeSyntax
    rfc1609.txt - Refers to uTCTimeSyntax
    rfc1778.txt - Refers to uTCTimeSyntax

Two RFC's have unusual date specifications and specify their own date
format. Both of these support Y2K compliant dates.

RFC1714 (RWhois) specifies date formats that are  not Y2K compliant,
but it also  support dates that are. Implementers of the RWhois
protocol should  only use the %MY4 format

RFC1834 (Whois++) requires the use of dates, but it didn't specify
the format, syntax, or representation of the date string to be used.

4.0 Disk Sharing


The RFC's which were categorized into this group were those related to
the Network File System (NFS).  Other popular disk sharing protocols
like SMB and AFS were referred to their respective trustee's for


The reference to time in this protocol is to set the length of
time to wait for the first try of a request; timeout.  Timeout time
in the NFS protocol is calculated rather than preserved. As such,
is not affected by the date.

SUN Microsystems states that there is known problem associated with
this protocol and the millennium change.

5.0 Games and Chat


The RFC's which were categorized into this group were related to the
Internet Relay Chat Protocol (IRC).


<<EDITOR'S NOTE:  We still need someone to go over IRC>>

6.0 Information Services & File Transfer


The RFC's which were categorized into this group were divided among
World Wide Web (WWW) protocols and File Transfer Protocols (FTP).  WWW
protocols include the Hypertext Transfer Protocol (HTTP), a variety of
Uniform Resource formats (URL, URAs, etc.) and the HyperText Markup
Language(HTML).  FTP protocols include the well known FTP protocol, the
Trivial File Transfer Protocol (TFTP) and a variety of extensions to
these protocols.  Other information services includes the Finger
Protocol and the LPD protocol.

HTTP 1.1 requires all newly generated date stamps to conform to RFC
1123 date formats which are Year 2000 compliant, but it also requires
acceptance of the older non-compliant RFC850 formats.  Some specific
recommendations are listed below and have been passed to the HTTP WG.

HTML 2.0 could allow a very subtle Year 2000 problem, but once again
this recommendation has been passed on the HTML WG.

<<EDITOR'S NOTE:  We need some serious help with this section because
there are a lot of things still to check.>>



The main IETF standards-track document on the HTTP protocol is
RFC2068 on HTTP 1.1.  It notes that historically three different
date formats have been used, and that one of them uses a two-digit
year field.  In section 3.3.1 it requires HTTP 1.1 implementations
to generate this RFC1123 format:

     Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 822, updated by RFC 1123

instead of this RFC850 format:

     Sunday, 06-Nov-94 08:49:37 GMT ; RFC 850, obsoleted by RFC 1036

Unfortunately, many existing servers, serving on the order of one
fifth of the current HTTP traffic, send dates in the ambiguous
RFC850 format.

Section 19.3 of the RFC2068 says this:

  o  HTTP/1.1 clients and caches should assume that an RFC-850 date
     which appears to be more than 50 years in the future is in fact
     in the past (this helps solve the "year 2000" problem).

This avoids a "stale cache" problem, which would cause the
user to see out-of-date data.

But to avoid unnecessary delays and bandwidth indicated in Scenario
2 below, this should be extended to say that a date which appears to
be more than 50 years in the past may be assumed to be in the
future, if a future date is legal for that field.

Scenario 3 indicates that servers may also want to follow these

Here is some more background and justification for these arguments.

The following headers use full dates:

        Expires:                # can be in the future
        If-Modified-Since:      # required to be in the past
        Last-Modified:          # required to be in the past
        Retry-After:            # can be in the future, also takes
                                # relative time - number of seconds

        If-Unmodified-Since:    # required to be in the past

Note that clock skew between hosts can lead to confusion here - see
the RFC for details.

Here are some scenarios of the implications of RFC850 dates, which
include stale caches, unnecessary requests for things which are
validly cached, delays for the user, extra bandwidth, and presenting
incorrect information to the user.

Some cases involve comparisons with the current time, and others may
involve comparisons between dates from different sources.  The
abbreviation "/99" is used to imply an RFC850 date with the value
"99" for the year.

RFC850 date from server

Scenario 1:
        If a client gets an Expires /99 date after the year 2000, it
        should interpret it as 1999, to avoid ending up with a stale
        cache entry.

        This is as already specified in RFC2068.

Scenario 2:
        If a client gets an Expires /00 date before the year 2000, and
        subsequently is faced with a choice to either retrieve the
        document from its cache or look for an updated copy, it may
        interpret it as the year 2000, to avoid the unnecessary delay
        and bandwidth of an extra request.

RFC850 date from client

Scenario 3:
        If a server gets an If-Modified-Since /99 date from a client
        after the year 2000, it should interpret it as 1999 when
        comparing with the local modification date, in order to
        possibly avoid sending a full GET response rather than a
        HEAD response.

        Note that an If-Modified-Since header must never be in the


In RFC1866, on HTML 2.0,the <META> tag allows the embedding of
recommended values for some HTTP headers, including Expires.  E.g.

    <META HTTP-EQUIV="Expires"
          CONTENT="Tue, 04 Dec 1993 21:29:02 GMT">

Servers should rewrite these dates into RFC1123 format if necessary.

7.0 Network & Transport Layer


The RFC's which were categorized into this group were the Internet
Protocol (IP) versions four and six, the Transmission Control Protocol
(TCP), the User Datagram Protocol (UDP), the Point-to-Point Protocol
(PPP) and its extensions, Internet Control Message Protocol (ICMP), the
Address Resolution Protocol (ARP) and Remote Procedure Call (RPC)
protocol.  A variety of less known protocols were also examined.


<<EDITOR'S NOTE:  Not done yet but Robert Elz is almost finished>>

8.0 Electronic Mail


The RFC's which were categorized into this group were the Simple Mail
Transfer Protocol (SMTP), Internet Mail Access Protocol (IMAP), Post
Office Protocol (POP), Multipurpose Internet Mail Exchange (MIME), and
X.400 to SMTP interaction.

After reviewing all mail-related RFCs, it was discovered that while
some obsolete standards required two-digit years, all currently-used
standards require four-digit years and are thus not prone to typical
Year 2000 problems.


RFCs 821 and 822, the main basis for SMTP mail exchange and message
format, originally required two-digit years. However, both of these
RFCs were later modified by RFC 1123 in 1989, which strongly
recommended 4-digit years.  Although there might be a few very old
SMTP systems using two-digit years, it is believed that almost all
mail sent over the Internet today uses four-digit years. Mail that
contains two-digit years in its SMTP headers will not "fail", but
might be missorted in message stores and mail user agents. This
problem is avoided entirely by taking the RFC 1123 change as a
requirement, rather than merely as a recommendation.

IMAP versions 1, 2, and 3 used two-digit years, but IMAP version 4
(defined in RFCs 1730 and 1732 in 1994) requires four-digit
years. There are still a few IMAP 2 servers and clients in use on
the Internet today, but IMAP version 4 has already take over almost
all of the IMAP market. Mail stored on an IMAP server or client with
two-digit years will not "fail", but could possibly be missorted or
prematurely expired.

RFC 1153 describes a format for digests of mailing lists, and uses
two-digit dates. This format is not widely used. The use of
two-digit dates could possibly cause missorting of stored messages.

RFC 1327, which describes mapping between X.400 mail and SMTP mail,
uses the UTCTime format.

RFC 1422 describes the structure of certificates that were used in
PEM (and are expected to be used in many other mail and non-mail
services). Those certificates use dates in UTCTime
format. Poorly-written software might prematurely expire or validate
a certificate based on comparisons of the date with the current
date, although no current software is known to do this.

9.0 Network Time Protocols


The RFC's which were categorized into this group were the Network Time
Protocol (NTP), and the Time Protocol.

NTP has been certified year 2000 compliant, while the Time Protocol
will "roll over" at Thu Feb 07 00:54:54 2036 GMT.  Since NTP is the
current defacto standard for network time this does not seem to be an


There is no reference anywhere in the NTP specification or
implementation to any reference epoch other than 1 January 1900. In
short, NTP doesn't know anything about the millennium.

>From the Time Protocol RFC (868):

    S: Send the time as a 32 bit binary number.


    The time is the number of seconds since 00:00 (midnight) 1 January
    1900 GMT, such that the time 1 is 12:00:01 am on 1 January 1900
    GMT; this base will serve until the year 2036.

10.0 Name Services


The RFC's which were categorized into this group were the Domain Name
System (DNS), it's advanced add on features (Incremental Zone Transfer,


<<EDITOR'S NOTE:  Still need this information>>

11.0 Network Management


The RFC's which were categorized into this group were the Simple
Network Management Protocol (SNMP), a large number of Management
Information Bases (MIBs) and the Common Management Information Protocol

Although a few discrepancies have been found and outlined below, none
of them should have an impacts on interoperability.


1.  Use of GeneralizedTime in CMOT (RFCs 1095 and 1189)

The standards for CMIP over TCP/IP specify an unusual use for the
GeneralizedTime type.  (GeneralizedTime has a four-digit representation
of the year.)

If the system generating the PDU does not have the current time, yet
does have the time since last boot, then GeneralizedTime can be used to
encode this information.  The time since last boot will be added to the
base time "0001 Jan 1 00:00:00.00" using the Gregorian calendar

This is really a "Year 0" problem rather than a Year 2000 problem, and
in any case, CMOT is not currently deployed.

2.  UTCTime in SNMP Definitions

UTCTime is an ASN.1 type that includes a two-digit representation of
the year.  There are several options for UTCTime in ASN.1, that vary in
precision and in local versus GMT, but these options all have two-digit
years.  The standards for SNMP definitions specify one particular


The first usage of UTCTime in the standards for SNMP definitions goes
all the way back to RFC 1303.  It has persisted unchanged up through
the current specifications in RFC 1902.  The role of UTCTime in SNMP
definitions is to record the history of an SNMP MIB module in the
module itself, via two ASN.1 macros:

    o   REVISION

Applications that store and use MIB modules need to be smart about
interpreting these UTCTimes, but with one exception, the times do not
actually flow in the network.  This one exception is the
appnNodeMibVersion object in the APPN MIB (currently draft-ietf-snanau-
appnmib-04.txt, but soon to be published as an RFC), which returns the
value of LAST-UPDATED from the version of the APPN MIB that an agent
has implemented.  An application that can correctly interpret UTCTimes,
by prepending a "19" or a "20" as appropriate, in the MIB modules it
has stored locally will be able to interpret the value of this object
correctly as well.

3.  Objects in the Printer MIB (RFC 1559)

There are two objects in the Printer MIB that allow use of a date as an
object value with no explicit guidance for formatting the value.  The
objects are prtInterpreterLangVersion and prtInterpreterVersion.  Both
are defined with a syntax of OCTET STRING.  The descriptions for the
objects allow the object value to contain a date, version code or other
product specific information to identify the interpreter or language.
The descriptions do not include an explicit statement recommending use
of a four-digit year when a date is used as the object value.

4.  Dates in Mobile Network Tracing Records (RFC 2041)

The RFC specifies trace headers and footers with date fields that are
character arrays of size 32.  While 32 characters certainly provide
enough room for a four-digit year, there's no explicit statement that
these years must be represented with four digits.

12.0 Network News


The RFC's which were categorized into this group were related to the
Network News Protocol (NNTP).

There does exist a problem in both NNTP and the Usenet News Message
Format.  They both specify two digit year format.  A working group has
been formed to update the network news protocols in general, and
addressing this problem is on their list of work items.


<<EDITOR'S NOTE:  Still need someone to look over the specifics but
Paul Hoffman pointed this out in passing.>>

13.0 Real Time Services


The RFC's which were categorized into this group were related to IP
Multicast, RTP, and Internet Stream Protocol.

<<EDITOR'S NOTE:  No input on this section to date.>>


14.0 Routing


The RFC's which were categorized into this group were Routing
Information Protocol (RIP), the Open Shortest Path First (OSPF)
protocol, Classless InterDomain Routing (CIDR),the Border Gateway
Protocol (BGP), and the InterDomain Routing Protocol (IDRP).

After careful examination both BGP and RIP have been found Year 2000

<<EDITOR'S NOTE:  We need more here.  The RIP statement is from Robert
Elz's statement in Munich.>>



The BGP4 protocol or the BGP4 FSM do not have knowledge of absolute
time. There is a notion of relative time inside BGP4, and this is
visible in the fact that BGP4 has five timers.

The five timers are not a problem, since they keep relative time, as
stated above. Below excerpts for proof from the RFC can be found:

* Hold timer:

The calculated value indicates the maximum number of seconds that
may elapse between the receipt of successive KEEPALIVE, and/or
UPDATE messages by the sender.

The suggested value for the Hold Time is 90 seconds.

* ConnectRetry timer:

The value of the initial timer shall be 60 seconds. The time shall
be doubled for each consecutive retry.

The suggested value for the ConnectRetry timer is 120 seconds.

* KeepAlive timer:

KeepAlive messages are sent periodically to ensure the liveness of
the connection.

The suggested value for the KeepAlive timer is 30 seconds.

* MinRouteAdvertisementInterval:

The parameter MinRouteAdvertisementInterval determines the minimum
amount of time that must elapse between advertisement of routes to a
particular destination from a single BGP speaker.

The suggested value for the MinRouteAdvertisementInterval is 30

* MinASOriginationInterval:

The parameter MinASOriginationInterval determines the minimum amount
of time that must elapse between successive advertisements of UPDATE
messages that report changes within the advertising BGP speaker's
own autonomous systems.

The suggested value for the MinASOriginationInterval is 15 seconds.

15.0 Security


The RFC's which were categorized into this group were kerberos
authentication protocol, Remote Authentication Dial In User Service
(RADIUS), One Time Password System (OTP), Privacy Enhanced Mail (PEM),
security extensions to a variety of protocols including (but not
limited to) RIPv2, HTTP, MIME, PPP, IP, Telnet and FTP.  Encryption and
authentication algorithms are also examined.

<<EDITOR'S NOTE:  We still need input for this section.  I can tell you
that OTP is compliant, but we need more input.>>


16.0 Virtual Terminal


The RFC's which were categorized into this group were Telnet and its
many extensions, as well as the Secure SHell (SSH) protocol.  The X
window systems was not considered since it is not an IETF protocol.
Official acknowledgement by the trustee's of the X window system was
given that the protocol will be examined by them.

Unencrypted Telnet and TN3270 have both been found to be Year 2000
Compliant.  The SSH protocols are also Year 2000 compliant.


17.0 Security Considerations

Although this document does consider the implications of various
security protocols, there is no need for additional security
considerations.  The effect of a potential year 2000 problem may cause
some security problems, but those problems are more of specific
applications rather than protocol deficiencies introduced in this

18.0 References

Because of the exhaustive nature of this investigation, the reader is
referred to the list of published RFC's evailable from the IETF
Secretariat or the RFC Editor, rather than republishing them here.

19.0 Editors Address

Philip J. Nesser II
Nesser & Nesser Consulting
13501 100th Ave N.E.
Suite 5202
Kirkland, WA 98052
(425)481-4303 (voice)
(425)482-9721 (fax)

20.0 Appendices

There were several appendices in the first draft of this document, but
they have not changed, and it was decided to leave them out of the
final version.  If the reader wished to see any of the following
information they should obtain the -00 version of this draft:

Appendix A:  List of RFC's divided by Area
Appendix B:  Automatic Script to Implement Methodology
Appendix C:  Output of the script in Appendix B on all RFC's from 1
             through 2134