Dynamic Host Configuration Working Group Rich Woundy
INTERNET DRAFT Kim Kinnear
Cisco Systems
November 2000
Expires May 2001
DHCP Lease Query
<draft-ietf-dhc-leasequery-00.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
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Internet-Drafts are draft documents valid for a maximum of six months
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The list of current Internet-Drafts can be accessed at
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Copyright Notice
Copyright (C) The Internet Society (2000). All Rights Reserved.
Abstract
Access concentrators that act as DHCP relay agents need to determine
the endpoint locations of IP addresses across public broadband access
networks such as cable, DSL, and wireless networks. Because ARP
broadcasts are undesirable in public networks, many access
concentrator implementations "glean" location information from DHCP
messages forwarded by its relay agent function. Unfortunately, the
typical access concentrator loses its gleaned information when the
access concentrator is rebooted or is replaced. This memo proposes
that when gleaned DHCP information is not available, the access
concentrator/relay agent obtains the location information directly
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from the DHCP server(s) using a new, lightweight DHCPLEASEQUERY
message.
1. Introduction
In many broadband access networks, the access concentrator needs to
associate an IP address lease to the correct endpoint location, which
includes knowledge of the host hardware address, the port or virtual
circuit that leads to the host, and/or the hardware address of the
intervening subscriber modem. This is particularly important when
one or more IP subnets are shared among many ports, circuits, and
modems. Representative cable and DSL environments are depicted in
Figures 1 and 2 below.
+--------+ +---------------+
| DHCP | | DOCSIS CMTS |
| Server |-...-| or DVB INA |-------------------
+--------+ | (Relay Agent) | | |
+---------------+ +------+ +------+
|Modem1| |Modem2|
+------+ +------+
| | |
+-----+ +-----+ +-----+
|Host1| |Host2| |Host3|
+-----+ +-----+ +-----+
Figure 1: Cable Environment for DHCPLEASEQUERY
+--------+ +---------------+
| DHCP | | DSL Access | +-------+
| Server |-...-| Concentrator |-...-| DSLAM |
+--------+ | (Relay Agent) | +-------+
+---------------+ | |
+------+ +------+
|Modem1| |Modem2|
+------+ +------+
| | |
+-----+ +-----+ +-----+
|Host1| |Host2| |Host3|
+-----+ +-----+ +-----+
Figure 2: DSL Environment for DHCPLEASEQUERY
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Knowledge of this location information benefits the access concentra-
tor in several ways:
1. The access concentrator can forward traffic to the access net-
work using the correct access network port, down the correct
virtual circuit, through the correct modem, to the correct
hardware address.
2. The access concentrator can perform IP source address verifica-
tion of datagrams received from the access network. The verif-
ication may be based on the datagram source hardware address,
the incoming access network port, the incoming virtual circuit,
and/or the transmitting modem.
3. The access concentrator can encrypt datagrams which can only be
decrypted by the correct modem, using mechanisms such as [BPI]
or [BPI+].
The premise of this document is that the access concentrator obtains
this location information primarily from "gleaning" information from
DHCP server responses sent through the relay agent. When location
information is not available from "gleaning", e.g. due to reboot,
the access concentrator can query the DHCP server(s) for location
information using the DHCPLEASEQUERY message. The DHCPLEASEQUERY
mechanism is the focus of this document.
The DHCPLEASEQUERY message is a new DHCP message type transmitted
from a DHCP relay agent to a DHCP server. The DHCPLEASEQUERY-aware
relay agent sends the DHCPLEASEQUERY message when it needs to know
the location of an IP endpoint. The DHCPLEASEQUERY-aware DHCP server
replies with a DHCPACK or DHCPNAK message. The DHCPACK response to a
DHCPLEASEQUERY message allows the relay agent to determine the IP
endpoint location, and the remaining duration of the IP address
lease.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC 2119].
This document uses the following terms:
o "access concentrator"
An access concentrator is a router or switch at the broadband
access provider's edge of a public broadband access network.
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This document assumes that the access concentrator includes the
DHCP relay agent functionality.
o "DHCP client"
A DHCP client is an Internet host using DHCP to obtain confi-
guration parameters such as a network address.
o "DHCP relay agent"
A DHCP relay agent is a third-party agent that transfers BOOTP
and DHCP messages between clients and servers residing on dif-
ferent subnets, per [RFC 951] and [RFC 1542].
o "DHCP server"
A DHCP server is an Internet host that returns configuration
parameters to DHCP clients.
o "downstream"
Downstream is the direction from the access concentrator towards
the broadband subscriber.
o "gleaning"
Gleaning is the extraction of location information from DHCP
messages, as the messages are forwarded by the DHCP relay agent
function.
o "location information"
Location information is information needed by the access concen-
trator to forward traffic to a broadband-accessible host. This
information includes knowledge of the host hardware address, the
port or virtual circuit that leads to the host, and/or the
hardware address of the intervening subscriber modem.
o "primary DHCP server"
The primary DHCP server in a DHCP Failover environment is con-
figured to provide primary service to a set of DHCP clients for
a particular set of subnet address pools.
o "secondary DHCP server"
The secondary DHCP server in a DHCP Failover environment is con-
figured to act as backup to a primary server for a particular
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set of subnet address pools.
o "stable storage"
Every DHCP server is assumed to have some form of what is called
"stable storage". Stable storage is used to hold information
concerning IP address bindings (among other things) so that this
information is not lost in the event of a server failure which
requires restart of the server.
o "upstream"
Upstream is the direction from the broadband subscriber towards
the access concentrator.
3. Background
The focus of this document is to enable access concentrators to send
DHCPLEASEQUERY messages to DHCP servers, to obtain location informa-
tion of broadband access network devices.
This document assumes that many access concentrators have an embedded
DHCP relay agent functionality. Typical access concentrators include
DOCSIS Cable Modem Termination Systems (CMTSs) [DOCSIS], DVB Interac-
tive Network Adapters (INAs) [EUROMODEM], and DSL Access Concentra-
tors.
The DHCPLEASEQUERY message is an optional extension to the DHCP pro-
tocol [RFC 2131]. Unlike previous DHCP message types, the DHCP relay
agent originates and sends the DHCPLEASEQUERY message to the DHCP
server, and processes the reply from the DHCP server (a DHCPACK or
DHCPNAK).
In a DHCP Failover environment [FAILOVER], the DHCPLEASEQUERY message
can be sent to the primary or secondary DHCP server. In order for the
secondary DHCP server to answer DHCPLEASEQUERY messages, the primary
DHCP server must send "interesting options" (such as the relay-
agent-information option) in Failover BNDUPD messages to the secon-
dary DHCP server, as recommended by section 7.1.1 of [FAILOVER].
The DHCPLEASEQUERY message is a query message only, and does not
affect the state of the IP address lease.
4. Design Goals
The core requirement of this document is to provide a lightweight
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mechanism for access concentrator implementations to obtain location
information for broadband access network devices. The specifics of
the broadband environment that drove the approach of this document
follow.
4.1. Broadcast ARP is Undesirable
The access concentrator can transmit a broadcast ARP Request [RFC
826], and observe the origin and contents of the ARP Reply, to recon-
struct the location information.
The ARP mechanism is undesirable for three reasons:
1. the burden on the access concentrator to transmit over multiple
access ports and virtual circuits (assuming that IP subnets
span multiple ports or virtual circuits),
2. the burden on the numerous subscriber hosts to receive and pro-
cess the broadcast, and
3. the ease by which a malicious host can misrepresent itself as
the IP endpoint.
4.2. SNMP and LDAP Client Functionality is Lacking
Access concentrator implementations typically do not have SNMP
management client interfaces nor LDAP client interfaces (although
they typically do include SNMP management agents). This is a primary
reason why this document does not leverage the proposed DHCP Server
MIB [DHCPMIB] nor leverage the proposed DHCP LDAP schema
[DHCPSCHEMA].
4.3. DHCP Relay Agent Functionality is Common
Access concentrators commonly act as DHCP relay agents. Furthermore,
many access concentrators already glean location information from
DHCP server responses, as part of the relay agent function.
The gleaning mechanism as a technique to determine the IP addresses
valid for a particular downstream link is preferred over other
mechanisms (ARP, SNMP, LDAP) because of the lack of additional net-
work traffic, but sometimes gleaning information can be incomplete.
The access concentrator usually cannot glean information from any
DHCP unicast (i.e. non-relayed) messages due to performance reasons.
Furthermore, the DHCP-gleaned location information often does not
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persist across access concentrator reboots (due to lack of stable
storage), and almost never persists across concentrator replacements.
4.4. DHCP Servers Are Most Reliable Source of Location Information
DHCP servers are the most reliable source of location information for
access concentrators, particularly when the location information is
dynamic and not reproducible by algorithmic means (e.g. when a sin-
gle IP subnet extends behind many broadband modems). DHCP servers
participate in all IP lease transactions (and therefore in all loca-
tion information updates) with DHCP clients, whereas access concen-
trators sometimes miss some important lease transactions.
In a DHCP Failover environment [FAILOVER], the access concentrator
can query either the primary or secondary DHCP server, so that no one
DHCP server is a single point of failure.
4.5. Minimal Additional Configuration is Required
Access concentrators can usually query the same set of DHCP servers
used for forwarding by the relay agent, thus minimizing configuration
requirements.
5. Protocol Overview
The access concentrator initiates all DHCPLEASEQUERY message conver-
sations. This document assumes that the access concentrator gleans
location information in its DHCP relay agent function. However, the
location information is usually unavailable after the reboot or
replacement of the access concentrator.
Suppose the access concentrator is a router, and further suppose that
the router receives an IP datagram to forward downstream to the pub-
lic broadband access network. If the location information for the
downstream next hop is missing, the access concentrator sends one or
more DHCPLEASEQUERY message(s), each containing the IP address of the
downstream next hop in the "ciaddr" field.
The DHCP servers that implement this protocol always sends a response
to the DHCPLEASEQUERY message: either a DHCPACK or DHCPNAK. The DHCP
server replies to the DHCPLEASEQUERY message with a DHCPACK message
if the "ciaddr" corresponds to an IP address about which the server
has definitive information (i.e., it is authorized to lease this IP
address). The server replies with a DHCPNAK message if the server
does not have definitive location information concerning the lease
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implied by the "ciaddr". Note that non-DHCPLEASEQUERY-literate DHCP
servers are expected to drop the DHCPLEASEQUERY message silently.
The DHCPACK message reply contains the physical address of the IP
address lease owner in the "htype", "hlen", and "chaddr" fields. The
reply often contains the time until expiration of the lease, and the
original contents of the Relay Agent Information option [RELAYAGEN-
TINFO]. The access concentrator uses the "chaddr" and Relay Agent
Information option to construct location information, which can be
cached on the access concentrator until lease expiration.
Any DHCP server which supports the DHCPLEASEQUERY message SHOULD save
the information from the most recent Relay Agent Information option
[RELAYAGENTINFO] associated with every IP address which it serves.
6. Protocol Details
6.1. Sending the DHCPLEASEQUERY Message
The DHCPLEASEQUERY message is typically sent by an access concentra-
tor. The DHCPLEASEQUERY message uses the DHCP message format as
described in [RFC 2131], and uses message number TBD in the DHCP Mes-
sage Type option (option 53). The DHCPLEASEQUERY message has the
following pertinent message contents:
o The values of htype, hlen, and chaddr MUST be set to 0. This
DHCP message is used for querying on IP address, not on hardware
address or DHCP client ID.
o The ciaddr MUST be set to the IP address of the lease to be
queried.
o The giaddr MUST be set to the IP address of the requestor (i.e.
the access concentrator). The giaddr is independent of the
ciaddr to be searched -- it is simply the return address of for
the DHCPACK or DHCPNAK message from the DHCP server.
o The Parameter Request List SHOULD be set to the options of
interest to the requestor. The interesting options are likely
to include the IP Address Lease Time option (option 51) and the
Relay Agent Information option (82).
The access concentrator SHOULD ensure that the ciaddr mentioned in
the DHCPLEASEQUERY message is a local subnet of the interface speci-
fied for the client.
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The DHCPLEASEQUERY message SHOULD be sent to a DHCP server which is
known to possess authoritative information concerning the IP address.
The DHCPLEASEQUERY message MAY be sent to more than one DHCP server,
and in the absence of information concerning which DHCP server might
possess authoritative information concerning the IP address, it
SHOULD be sent to all DHCP servers configured for the associated
relay agent (if any are known).
6.2. Receiving the DHCPLEASEQUERY Message
A DHCPLEASEQUERY message MUST have a non-zero ciaddr and MUST have a
non-zero giaddr. The DHCP server which receives a DHCPLEASEQUERY
message MUST base its response (if any) on the IP address represented
by the ciaddr in the DHCPLEASEQUERY message. The giaddr is used only
for the destination address of any generated response and, while
required, is not otherwise used in generating the response to the
DHCPLEASEQUERY message.
6.3. Responding to the DHCPLEASEQUERY Message
The DHCP server MUST respond to a DHCPLEASEQUERY message with a
DHCPACK message if the ciaddr corresponds to an IP address which is
managed by the DHCP server.
The DHCP server SHOULD respond to a DHCPLEASEQUERY message with a
DHCPACK if the ciaddr corresponds to an IP address about which the
DHCP server has definitive information, even if the ciaddr does not
correspond to an IP address which might be dynamically allocated by
the DHCP server -- for example, a statically allocated IP address
which is known to be reserved for a particular device by the DHCP
server.
The DHCP server MUST respond to the DHCPLEASEQUERY with a DHCPNAK if
the DHCP server supports the DHCPLEASEQUERY message but does not have
definitive information concerning the IP address in the ciaddr. When
responding with a DHCPNAK, the DHCP server SHOULD NOT include other
DHCP options in the response.
A DHCP server which does not support the DHCPLEASEQUERY message MUST
NOT respond to the DHCPLEASEQUERY message.
When responding to a DHCPLEASEQUERY message with a DHCPACK:
o If the IP Address Lease Time (option 51) is specified in the
Parameter Request List and if there is a currently valid lease
for the IP address specified in the ciaddr, then the DHCP server
MUST return this option in the DHCPACK with its value equal to
the time remaining until lease expiration. If there is no valid
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lease for the IP address, then the server MUST NOT return the IP
Address Lease Time option (option 51). This allows the reques-
tor (i.e. the access concentrator) to determine if there is
currently a valid lease for the IP address as well as the time
until the lease expiration.
A request for the Renewal (T1) Time Value option or the Rebind-
ing (T2) Time Value option in the Parameter Request List of the
DHCPLEASEQUERY message MUST be handled like the IP Address Lease
Time option is handled. If there is a valid lease, then the
DHCP server SHOULD return these options (when requested) with
the remaining time until renewal or rebinding, respectively. If
there is not currently a valid lease for this IP address, the
DHCP server MUST NOT return these options.
o If the DHCP server has information about the most recent device
associated with the IP address specified in the ciaddr, then the
DHCP server MUST encode the physical address of that device in
the htype, hlen, and chaddr fields. Otherwise, the values of
htype, hlen, and chaddr MUST be set to 0 in the DHCPACK. If the
IP Address Lease Time (option 51) is returned in the DHCPACK
(indicating a currently valid lease by some device for this IP
address), the DHCP server MUST encode the physical address of
the device which owns the lease in the htype, hlen, and chaddr
fields.
o If the Relay Agent Information (option 82) is specified in the
Parameter Request List and if the DHCP server has saved the
information contained in the most recent Relay Agent Information
option, the DHCP server MUST include that information in a Relay
Agent Information option in the DHCPACK.
In environments with non-DHCP-enabled devices, when the DHCP
server knows the network access information (perhaps through
server configuration), the DHCP server MAY generate its own
Relay Agent Information option value in the DHCPACK; in such
cases, the DHCP server MUST generate an option value that the
access concentrator can process.
o The DHCPACK message SHOULD include the values of all other
options not specifically discussed above that were requested in
the Parameter Request List of the DHCPLEASEQUERY message.
The DHCP server uses information from the lease binding database to
supply the DHCPACK option values.
In order to accommodate DHCPLEASEQUERY messages sent to a DHCP Fail-
over secondary server [FAILOVER] when the primary server is down, the
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primary server MUST communicate the Relay Agent Information option
(82) values to the secondary server via the DHCP Failover BNDUPD mes-
sages.
The server expects a giaddr in the DHCPLEASEQUERY message, and uni-
casts the DHCPACK or DHCPNAK to the giaddr. If the giaddr field is
zero, then the DHCP server does not reply to the DHCPLEASEQUERY mes-
sage.
6.4. Receiving a DHCPACK or DHCPNAK response to the DHCPLEASEQUERY Mes-
sage
When a DHCPACK message is received in response to the DHCPLEASEQUERY
message and the DHCPACK has an IP Address Lease Time option value
that is non-zero, it means that there is a currently active lease for
this IP address in this DHCP server. The access concentrator SHOULD
use the information in the htype, hlen, and chaddr fields of the
DHCPACK as well as any Relay Agent Information option information
included in the packet to refresh its location information for this
IP address.
When a DHCPACK message is received in response to the DHCPLEASEQUERY
message and the DHCPACK has no IP Address Lease Time option (though
one was requested in the Parameter Request List), that means that
there is no currently active lease for the IP address present in the
DHCP server. In this case, the access concentrator SHOULD cache this
information in order to prevent unacceptable loads on the access con-
centrator and the DHCP server in the face of a malicious or seriously
compromised device downstream of the access concentrator.
In either case, when a DHCPACK message is received in response to a
DHCPLEASEQUERY message, it means that the DHCP server which responded
is a DHCP server which manages the IP address present in the ciaddr,
and the Relay Agent SHOULD cache this information for later use.
When a DHCPNAK message is received by an access concentrator which
has sent out a DHCPLEASEQUERY message, it means that the DHCP server
contacted supports the DHCPLEASEQUERY message but that the DHCP
server not have definitive information concerning the IP address con-
tained in the ciaddr of the DHCPLEASEQUERY message. It doesn't
manage this IP address.
The access concentrator SHOULD cache this information, and only
infrequently direct a DHCPLEASEQUERY message to a DHCP server that
responded to a DHCPLEASEQUERY message for a particular ciaddr with a
DHCPNAK.
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6.5. Receiving no response to the DHCPLEASEQUERY Message
When an access concentrator receives no response to a DHCPLEASEQUERY
message, there are several possible reasons:
o The DHCPLEASEQUERY or a corresponding DHCPACK or DHCPNAK were
lost during transmission or the DHCPLEASEQUERY arrived at the
DHCP server but it was dropped because the server was too busy.
o The DHCP server doesn't support DHCPLEASEQUERY.
In the first of the cases above, a retransmission of the DHCPLEASE-
QUERY would be appropriate, but in the second of the two cases, a
retransmission would not be appropriate. There is no way to tell
these two cases apart (other than, perhaps, because of a DHCP
server's response to other DHCPLEASEQUERY messages indicating that it
supports the DHCPLEASEQUERY message).
An access concentrator which utilizes the DHCPLEASEQUERY message
SHOULD attempt to resend DHCPLEASEQUERY messages to servers which do
not respond to them using a backoff algorithm for the retry time that
approximates an exponential backoff. The access concentrator SHOULD
adjust the backoff approach such that DHCPLEASEQUERY messages do not
arrive at a server which is not otherwise known to support the
DHCPLEASEQUERY message at a rate of not more than approximately one
packet every 10 seconds, and yet (if the access concentrator needs to
send DHCPLEASEQUERY messages) not less than one DHCPLEASEQUERY per
minute.
7. Security Considerations
Access concentrators that use DHCP gleaning, refreshed with
DHCPLEASEQUERY messages, will maintain accurate location information.
Location information accuracy ensures that the access concentrator
can forward data traffic to the intended location in the broadband
access network, can perform IP source address verification of
datagrams from the access network, and can encrypt traffic which can
only be decrypted by the intended access modem (e.g. [BPI] and
[BPI+]). As a result, the access concentrator does not need to
depend on ARP broadcasts across the access network, which is suscep-
tible to malicious hosts which masquerade as the intended IP end-
points. Thus, the DHCPLEASEQUERY message allows an access concentra-
tor to provide considerably enhanced security.
DHCP servers SHOULD prevent exposure of location information (partic-
ularly the mapping of hardware address to IP address lease, which can
be an invasion of broadband subscriber privacy) by leveraging DHCP
authentication [DHCPAUTH]. With respect to authentication, the
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access concentrator acts as the "client". The use of "Authentication
Protocol 0" (using simple unencoded authentication token(s) between
the access concentrator and the DHCP server) is straightforward. The
use of "Authentication Protocol 1" (using "delayed authentication")
is under investigation, since it requires two message round trips.
Access concentrators SHOULD minimize potential denial of service
attacks on the DHCP servers by minimizing the generation of
DHCPLEASEQUERY messages. In particular, the access concentrator
should employ negative caching (i.e. cache both DHCPACK and DHCPNAK
responses to DHCPLEASEQUERY messages) and ciaddr restriction (i.e.
don't send a DHCPLEASEQUERY message with a ciaddr outside of the
range of the attached broadband access networks). Together, these
mechanisms limit the access concentrator to transmitting one
DHCPLEASEQUERY message (excluding message retries) per legitimate
broadband access network IP address after a reboot event.
8. Acknowledgments
Jim Forster, Joe Ng, Guenter Roeck, and Mark Stapp contributed
greatly to the initial creation of the DHCPLEASEQUERY message.
Patrick Guelat suggested several improvements to support static IP
addressing.
Ralph Droms, Mark Stapp and Andy Sudduth contributed to making the
draft more complete and helped add clarity.
9. References
[RFC 826] Plummer, D., "Ethernet Address Resolution Protocol: Or con-
verting network protocol addresses to 48.bit Ethernet address for
transmission on Ethernet hardware", RFC 826, November 1982.
[RFC 951] Croft, B., Gilmore, J., "Bootstrap Protocol (BOOTP)", RFC
951, September 1985.
[RFC 1542] Wimer, W., "Clarifications and Extensions for the
Bootstrap Protocol", RFC 1542, October 1993.
[RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[RFC 2131] Droms, R., "Dynamic Host Configuration Protocol", RFC
2131, March 1997.
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[RFC 2132] Alexander, S., Droms, R., "DHCP Options and BOOTP Vendor
Extensions", Internet RFC 2132, March 1997.
[BPI] CableLabs, "Baseline Privacy Interface Specification", SP-BPI-
I02-990319, March 1999, available at http://www.cablemodem.com/.
[BPI+] CableLabs, "Baseline Privacy Plus Interface Specification",
SP-BPI+-I04-000407, April 2000, available at
http://www.cablemodem.com/.
[DHCPAUTH] Droms, R., Arbaugh, W., "Authentication for DHCP Mes-
sages", draft-ietf-dhc-authentication-14.txt, July 2000.
[DHCPMIB] Hibbs, R., Waters, G., "Dynamic Host Configuration Protocol
(DHCP) Server MIB", draft-ietf-dhc-server-mib-05.txt, November
2000.
[DHCPSCHEMA] Bennett, A., Volz, B., "DHCP Schema for LDAP", draft-
ietf-dhc-schema-02.txt, March 2000.
[DOCSIS] CableLabs, "Data-Over-Cable Service Interface Specifica-
tions: Cable Modem Radio Frequency Interface Specification SP-
RFI-I05-991105", November 1999.
[EUROMODEM] ECCA, "Technical Specification of a European Cable Modem
for digital bi-directional communications via cable networks",
Version 1.0, May 1999.
[FAILOVER] Droms, R., Kinnear, K., Stapp, M., Volz, B., Gonczi, S.,
Rabil, G., Dooley, M., Kapur, A., "DHCP Failover Protocol",
draft-ietf-dhc-failover-08.txt, November 2000.
[RELAYAGENTINFO] Patrick, M., "DHCP Relay Agent Information Option",
draft-ietf-dhc-agent-options-12.txt, October 2000.
10. Author's information
Rich Woundy
Kim Kinnear
Cisco Systems
250 Apollo Drive
Chelmsford, MA 01824
Phone: (978) 244-8000
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EMail: rwoundy@cisco.com
kkinnear@cisco.com
11. Full Copyright Statement
Copyright (C) The Internet Society (2000). All Rights Reserved.
This document and translations of it may be copied and furnished to oth-
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FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT
LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT
INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FIT-
NESS FOR A PARTICULAR PURPOSE.
Open Issues
These issues need to be resolved by the working group:
1. May the DHCPLEASEQUERY message be sent by parties other than
relay agents?
[Resolved] Sure, you can't stop them in any case.
2. Should the DHCPLEASEQUERY message be extended to find lease
information by physical address or by DHCP Client ID? This
might be useful for non-router access concentrators.
Woundy & Kinnear Expires May 2001 [Page 15]
Internet Draft DHCP Lease Query November 2000
[Resolved] There has been no working group interest in this
aspect of the DHCPLEASEQUERY message, so it has been specifi-
cally excluded.
3. How can the DHCPLEASEQUERY message exchange be modified to lev-
erage the better DHCP authentication protocol types?
[Unresolved]
Woundy & Kinnear Expires May 2001 [Page 16]
