Subject: RE: Protocol Action: The User Class Option for DHCP to Proposed S tandard

From: Bernie Volz <[email-masked]>
Date: Fri, 20 Oct 2000 10:54:45 -0400

While using a new option number is certainly a solution, it likely means
we'll have to keep the old one around forever.

As it should likely be fairly easy for a server to detect the difference,
perhaps that needs to be described in the draft/RFC ... I assume that
Microsoft's implementation is just to send the user class string in the
option. As this is likely to be ASCII, it should be easy for a server to
look at the received option and detect a 'problem' if the first class length
is greater than the option length (as that should not be possible). In that
case, it could assume that it is an old Microsoft client and use that option
format? Or, it would need to drop that option OR the entire packet as being
mal-formed.

- Bernie Volz

-----Original Message-----
From: A. Gregory Rabil [mailto:[email-masked]]
Sent: Friday, October 20, 2000 9:20 AM
To: DHCPv4 discussion list
Cc: [email-masked]
Subject: RE: Protocol Action: The User Class Option for DHCP to Proposed
Standard

Jerome,
Of course I understand that Microsoft's implementation long predated the
User Class as Proposed Standard.  My question goes more toward the fact
that although MS may update future clients, server vendors will likely
have to deal with W2K clients for quite some time anyway.  It seems that
it would have been prudent to select a new option number for the new
format, just to ease the transition, then phase out 77 and use it for
something else.

My $0.02,
Greg

-----Original Message-----
From: Jerome Privat [mailto:[email-masked]]
Sent: Friday, October 20, 2000 3:02 AM
To: [email-masked]'; [email-masked]
Cc: [email-masked]'
Subject: RE: Protocol Action: The User Class Option for DHCP to Proposed
Standard

Greg,

Implementation for existing Microsoft 2000 clients was written well before
the User Class was accepted as Proposed Standard (which just happenned now).
So it is normal it does not support what is in the spec now (the same is
true for other pre-standard implementations).

That being said, the syntax in the draft was discussed with people from
Microsoft (Ann Demirtjis at the time, who co-authored the draft). So I would
expect next versions of MS clients to adhere to the spec.

Jerome

Jerome Privat
Northstream AB

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Thursday, October 19, 2000 6:30 PM
To: [email-masked]
Subject: RE: Protocol Action: The User Class Option for DHCP to Proposed
Standard

I apologize for the repost, but I hear crickets... anyone care to comment?

Greg

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On
Behalf Of A. Gregory Rabil
Sent: Wednesday, October 11, 2000 6:09 PM
To: DHCPv4 discussion list
Subject: RE: Protocol Action: The User Class Option for DHCP to Proposed
Standard

Has anyone given thought to the implications involved with the existing
Microsoft Windows 2000 DHCP clients that use this option?  Specifically, MS
W2K clients use option 77, but they don't have/support the multiple user
classes as defined in this latest revision.  This seems like a very big
interoperability problem for servers that are using this option with W2K
clients today.

Greg

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf
Of The IESG
Sent: Tuesday, October 10, 2000 2:16 PM
To: IETF-Announce: ;
Cc: RFC Editor; Internet Architecture Board; [email-masked]
Subject: Protocol Action: The User Class Option for DHCP to Proposed
Standard

The IESG has approved the Internet-Draft 'The User Class Option for
DHCP' <draft-ietf-dhc-userclass-10.txt> as a Proposed Standard.  This
document is the product of the Dynamic Host Configuration Working
Group.  The IESG contact persons are Erik Nordmark and Thomas Narten.

Technical Summary

This document defines a DHCP option that is used by a DHCP client to
optionally identify the type or category of user or applications it
represents. The information contained in this option is an opaque
field that represents the user class of which the client is a member.
Based on this class, a DHCP server selects the appropriate address
pool to assign an address to the client and the appropriate
configuration parameters.  This option should be configurable by a
user.

Working Group Summary

There was strong support for this option within the WG, and no issues
were raised during the IETF Last Call.

Protocol Quality

This document has been reviewed for the IESG by Thomas Narten.

---

From: "A. Gregory Rabil" <[email-masked]>
Date: Fri, 20 Oct 2000 11:45:28 -0400

Unfortunately, I don't think it is possible to detect a 'problem'.  For
example, assume a User Class of the following:

!SomeThirtyThreeCharacterUserClass

Note that the '!' is a decimal 33.  Therefore, if the option code 77 was
followed by a length byte of decimal 34, then the above ascii string
(including the prefixed '!').  In this case, this is valid for both
formats of the UserClass option.  It appears impossible to determine if
the User Class is "SomeThirtyThreeCharacterUserClass" or
"!SomeThirtyThreeCharacterUserClass".

Regards,
Greg

-----Original Message-----
From: Bernie Volz [mailto:[email-masked]]
Sent: Friday, October 20, 2000 10:55 AM
To: [email-masked]'; DHCPv4 discussion list
Cc: [email-masked]
Subject: RE: Protocol Action: The User Class Option for DHCP to Proposed
Standard

- Bernie Volz

-----Original Message-----
From: A. Gregory Rabil [mailto:[email-masked]]
Sent: Friday, October 20, 2000 9:20 AM
To: DHCPv4 discussion list
Cc: [email-masked]
Subject: RE: Protocol Action: The User Class Option for DHCP to Proposed
Standard

Jerome,

My $0.02,
Greg

-----Original Message-----
From: Jerome Privat [mailto:[email-masked]]
Sent: Friday, October 20, 2000 3:02 AM
To: [email-masked]'; [email-masked]
Cc: [email-masked]'
Subject: RE: Protocol Action: The User Class Option for DHCP to Proposed
Standard

Greg,

Jerome

Jerome Privat
Northstream AB

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Thursday, October 19, 2000 6:30 PM
To: [email-masked]
Subject: RE: Protocol Action: The User Class Option for DHCP to Proposed
Standard

Greg

-----Original Message-----

Greg

-----Original Message-----

Technical Summary

Working Group Summary

Protocol Quality