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dhc-minutes-94dec.txt
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1995-02-28
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CURRENT_MEETING_REPORT_
Reported by Walt Wimer/CMU
Minutes of the Dynamic Host Configuration Working Group (DHC)
The DHC Working Group met on 7 December and 9 December at the 31st IETF.
Document Status
The most recent Internet-Draft of the DHCP specification includes
several changes based on the results of the latest interoperability
testing. Based on the results of that testing, and a review of the
Standards process RFC, the working group decided it would be appropriate
to ask that DHCP be considered for ``Draft Standard'' status. As soon
as a revision of the current Internet-Draft is completed, the
specification for DHCP will be submitted for review.
A few, minor changes have been made to RFC 1541 based on questions
raised during the latest interoperability testing. Two new options have
been defined since RFC 1533: 62, NetWare/IP domain and 63, NetWare/IP
option.
The working group agreed that the minimum lease requirement (one hour)
should be made advisory rather than mandatory.
Implementations
The following list of implementations was compiled from information
given by working group attendees.
_____________________________________________________________________
|| | | | ||
|| Vendor |Client |Server |Relay agent ||
||___________________|___________________|_______________|_____________||
|| FTP Software |DOS/Windows |Windows | ||
||___________________|___________________|NT_(beta)______|_____________||
|| SunSoft |DOS/Windows |Solaris 2.0 |in server ||
||___________________|Solaris_(beta?)____|_______________|_____________||
|| Microsoft |DOS/Windows |NT |in server ||
|| |NT | | ||
||___________________|Windows95_beta_____|_______________|_____________||
|| Competitive |??? |Solaris | ||
||_Automation________|___________________|_______________|_____________||
|| Apple |Newton | | ||
||___________________|Mac_(beta)_________|_______________|_____________||
|| WIDE project |Unix, BSD386 |Unix, BSD386 |Unix, BSD386 ||
||_(free,_avail_2/95)|News,_SunOS________|News,_SunOS____|News,_SunOS_ ||
||_Silicon_Graphics__|IRIX_(soon)________|IRIX___________|_____________||
|| Hewlett Packard |X-terminal |HP/UX (June 95)|in server ||
||___________________|___________________|_______________|HP_router____||
|| IBM |OS/2 (soon) |OS/2 (soon) | ||
|| |AIX (soon) |AIX (soon) | ||
||___________________|___________________|AS/400_(soon)__|_____________||
|| cisco Systems |Terminal server? | |routers ||
|| |(proxy for | | ||
||___________________|terminal_clients?)_|_______________|_____________||
|| Novell |NetWare/IP |NetWare/IP | ||
||___________________|(spring)___________|(later)________|_____________||
|| Shiva |Proxy for | | ||
||___________________|dial-in_clients____|_______________|_____________||
Future Interoperability Test
There was some discussion of a future interoperability test. Suggested
venues include Bucknell University (summer '95), CMU (no specific time),
next IETF (March '95) and remote via the Internet (?!?!). The working
group will hold a discussion about the next interoperability testing via
electronic mail.
Outstanding Issues
The working group discussed some outstanding issues and generated some
solutions:
o New options: TFTP server address, bootfile name, to be registered
with IANA.
o Some clients will already have an IP address, not otherwise
registered or managed by DHCP. Those clients will only want local
configuration parameters, not an address. A new DHCP message,
DHCPINFORM, will be defined for parameter requests.
o There was some question about the definition and interpretation of
``client identifiers.'' The working group confirmed that a
``client identifier'' is an opaque, unique identifier. Text will
be added to the protocol specification to clarify this issue and to
advise that ``client identifiers'' must be unique. ``Client
identifier'' type 0 will indicate ``an opaque string of
characters.''
The issue of security was discussed. The primary concern is to detect
and avoid spoof/unauthorized servers. Some sites are also concerned
about unauthorized clients. The consensus was that a public key
identification and authorization mechanism should be developed as an
optional DHCP service.
Ralph Droms presented a preliminary proposal for a server-server
protocol to allow automatic management of DHCP bindings by multiple DHCP
servers at a single site. The goals are to increase availability and
reliability through redundancy of address allocation and binding
servers, and through load sharing. The basic model, based on a proposal
by Jeff Mogul, is to assign each allocatable address and allocated
binding to a specific ``owner'' server. That owner has modification
privileges, while all other servers have read-only privileges. Servers
use TCP connections and a simple protocol to replicate copies of new
bindings and transfer ownership of addresses to balance the pool of
available addresses.
The hard part is bindings that are released early, prior to expiration.
Those released bindings must be reported to all other servers, so those
servers do not respond with stale data in the future. However, servers
may be inaccessible. The proposed solution was to add an ``owner''
option; clients would select responses from the ``owner'' in favor of
all other responses.
The suggestion was made that multiple DHCP servers might be able to use
an underlying distributed database like DNS, NIS+ or Oracle. Questions
were raised about the scalability of the proposed scheme -- suppose many
clients send simultaneous update requests, how often should updates be
replicated, what about combinatoric explosion with the number of
servers?
IPv6 Issues
The second meeting began with a discussion of several IPv6 issues. IPv6
address configuration has three basic forms:
1. Intra-link scope address (client forms address all on its own)
2. ``Stateless'' servers (e.g., in routers using some simple
assignment algorithm)
3. Stateful servers (`a la IPv4 DHCP)
Regardless of how addresses are managed, IPv6 will need some other
mechanism(s) to obtain other configuration parameters. Some members of
the IPv6 design team claim there will be no other parameters.
The following action items were identified:
o Someone to enumerate all IPv6 network layer parameters.
Mike Carney volunteered.
o Extensions/changes to DHCP protocol format for IPv6.
Walt Wimer volunteered.
Dynamic Addressing
Next, the working group discussed the problem of dynamic updates to DNS
from DHCP information (dynamic addressing). For simple registration of
DNS hostnames for individual DHCP clients, what should we do? Should
client be responsible for contacting DNS server directly, or should DHCP
server contact DNS on behalf of client? It will be necessary to clarify
DNS configuration/update mechanism with DNS Working Group. One solution
to the question of who does the update would be to define a DHCP option
for client to say whether it will do the registration with DNS directly
or whether client wants DHCP server to take care of it. DHCP server may
need a way to veto the client's preference. This permits a simple
client (such as an embedded hub, probe, etc.) to let the DHCP server do
everything (DHCP server probably has necessary credentials to update DNS
while client probably does not). Or, a more sophisticated client can
update its ``home'' DNS directly (for example, a mobile notebook
computer belonging to XYZ, Inc. can be taken to an IETF get a local IP
address from the IETF DHCP server, but then directly update XYZ.COM's
DNS server in order to maintain an XYZ.COM name). The problem of name
collisions was unresolved - should the client or the server be
responsible? Masataka Ohta volunteered to do a DHCP-to-DNS interaction
proposal
DHCP and SNMP
Finally, the working group considered DHCP and SNMP. The working group
chair asked if there were any MIB writers in the audience. The scribe
thought there was a volunteer but did not catch the name.