< draft-wkumari-dhc-capport-07.txt   draft-wkumari-dhc-capport-08.txt >
Network Working Group W. Kumari Network Working Group W. Kumari
Internet-Draft Google Internet-Draft Google
Intended status: Informational O. Gudmundsson Intended status: Informational O. Gudmundsson
Expires: June 25, 2015 Shinkuro Inc. Expires: July 31, 2015 Shinkuro Inc.
P. Ebersman P. Ebersman
Comcast Comcast
S. Sheng S. Sheng
ICANN ICANN
December 22, 2014 January 27, 2015
Captive-Portal identification in DHCP / RA Captive-Portal identification in DHCPv4 / RA
draft-wkumari-dhc-capport-07 draft-wkumari-dhc-capport-08
Abstract Abstract
In many environments (such as hotels, coffee shops and other In many environments offering short-term or temporary Internet access
establishments that offer Internet service to customers), it is (such as coffee shops), it is common to start new connections in a
common to start new connections in a captive portal mode, i.e. highly captive portal mode. This highly restricts what the customer can do
restrict what the customer can do until the customer has accepted until the customer has authenticated.
terms of service, provided payment information and / or
authenticated.
This document describes a DHCP option (and an RA extension) to inform This document describes a DHCPv4 option (and an IPv6 RA extension) to
clients that they are behind some sort of captive portal device, and inform clients that they are behind some sort of captive portal
that they will need to authenticate to get Internet Access. device, and that they will need to authenticate to get Internet
Access.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
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Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 25, 2015. This Internet-Draft will expire on July 31, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3
2. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. DNS Redirection . . . . . . . . . . . . . . . . . . . . . 4 2.1. DNS Redirection . . . . . . . . . . . . . . . . . . . . . 4
2.2. HTTP Redirection . . . . . . . . . . . . . . . . . . . . 4 2.2. HTTP Redirection . . . . . . . . . . . . . . . . . . . . 4
2.3. IP Hijacking . . . . . . . . . . . . . . . . . . . . . . 5 2.3. IP Hijacking . . . . . . . . . . . . . . . . . . . . . . 4
3. The Captive-Portal DHCP Option . . . . . . . . . . . . . . . 5 3. The Captive-Portal IPv4 DHCP Option . . . . . . . . . . . . . 4
4. The Captive-Portal RA Option . . . . . . . . . . . . . . . . 6 4. The Captive-Portal IPv6 RA Option . . . . . . . . . . . . . . 5
5. Use of the Captive-Portal Option . . . . . . . . . . . . . . 7 5. Use of the Captive-Portal Option . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 8 7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
9. Normative References . . . . . . . . . . . . . . . . . . . . 9 9. Normative References . . . . . . . . . . . . . . . . . . . . 8
Appendix A. Changes / Author Notes. . . . . . . . . . . . . . . 9 Appendix A. Changes / Author Notes. . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
In many environments, users need to connect to a captive portal In many environments, users need to connect to a captive portal
device and agree to an acceptable use policy and / or provide billing device and agree to an acceptable use policy and / or provide billing
information before they can access the Internet. information before they can access the Internet.
In order to present the user with the captive portal web page, many Many devices perform DNS, HHTP, and / or IP hijacks in order to
devices perform DNS and / or HTTP and / or IP hijacks. In addition present the user with the captive portal web page. These kludgy
to being kludgy hacks, these techniques resemble attacks that DNSSEC workarounds and techniques resemble attacks that DNSSEC and TLS are
and TLS are intended to protect against. In an attempt to discourage intended to protect against. This document describes a DHCPv4 option
the deliberate subversion of basic security tools, this document (Captive Portal) and an IPv6 Router Advertisement (RA) extension that
describes a DHCP option (Captive-Portal) and an IPv6 Router informs clients that they are behind a captive portal device and how
Advertisement (RA) extension that informs clients that they are to contact it.
behind a captive portal device, and how to contact it.
This document neither condones nor condemns the use of captive This document neither condones nor condemns the use of captive
portals; instead, it recognises that their apparent necessity, and portals; instead, it recognises that their apparent necessity, and
attempts to improve the user experience. attempts to improve the user experience.
The technique described in this document mainly improve the user [ Ed note: This solution complements 802.11U / WiFi Passpoint. It
experience when first connecting to a network behind a captive can be quickly and easily deployed, and works on wired as well ]
portal. It may also help if the captive portal access times out
after connecting, but this is less reliable.
1.1. Requirements notation 1.1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Background 2. Background
Many Internet Service Providers (ISPs) that offer public Internet Some ISPs implement a captive portal (CP) - a system that intercepts
access require the user to accept an Acceptable Use Policy (AUP) and user requests and redirects them to an interstitial login page - in
/ or provides billing information (such as their last name and room order to require the user accept an Acceptable Use Policy (AUP),
number in a hotel, credit card information, etc.) through a web provide billing information, or otherwise authenticate a user prior
interface before the user can access the Internet. to allowing them to access the Internet.
In order to meet this requirement, some ISPs implement a captive
portal (CP) - a system that intercepts user requests and redirects
them to an interstitial login page.
Captive portals intercept and redirects user requests in a number of Captive portals intercept and redirect user requests in a number of
ways, including: ways, including:
o DNS Redirection o DNS Redirection
o IP Redirection o IP Redirection
o HTTP Redirection o HTTP Redirection
o Restricted scope addresses o Restricted scope addresses
o Traffic blocking (until the user is authenticated) o Traffic blocking (until the user is authenticated)
In order to ensure that the user is unable to access the Internet In order to ensure that the user is unable to access the Internet
until they have satisfied the requirements, captive portals usually until they have satisfied the requirements, captive portals usually
implement IP based filters, or place the user into a restricted VLAN implement IP based filters, or place the user into a restricted VLAN
(or restricted IP range) until after they have been authorized / (or restricted IP range) until after they have been authorized /
satisfied. satisfied.
These techniques are very similar to attacks that protocols (such as These techniques are very similar to attacks that protocols (such as
VPNs, DNSSEC, TLS) are designed to protect against. The interaction VPNs, DNSSEC, TLS) are designed to protect against. The interaction
of the these protections and the interception leads to poor user of these protections and the interception leads to poor user
experiences, such as long timeouts, inability to reach the captive experiences, such as long timeouts, inability to reach the captive
portal web page, etc. The interception may also leak user portal web page, etc. The interception may also leak user
information (for example, if the captive portal intercepts and logs information (for example, if the captive portal intercepts and logs
an HTTP Cookie, or URL of the form http://fred:password@example.com). an HTTP Cookie, or URL of the form http://fred:password@example.com).
The user is often unaware of what is causing the issue (their browser The user is often unaware of what is causing the issue (their browser
appears to hang, saying something like "Downloading Proxy Script", or appears to hang, saying something like "Downloading Proxy Script", or
simply "The Internet doesn't work"), and they become frustrated. simply "The Internet doesn't work"), and they become frustrated.
This may results in them not purchasing the Internet access provided This may result in them not purchasing the Internet access provided
by the captive portal. The connectivity attempts may also facilitate by the captive portal. The connectivity attempts may also facilitate
OS fingerprinting even before a client attempts to connect to the OS fingerprinting even before a client attempts to connect to the
portal itself. portal itself.
2.1. DNS Redirection 2.1. DNS Redirection
The CP either intercepts all DNS traffic or advertises itself (for The CP either intercepts all DNS traffic or advertises itself (for
example using DHCP) as the recursive server for the network. Until example using DHCP) as the recursive server for the network. Until
the user has authenticated to the captive portal, the CP responds to the user has authenticated to the captive portal, the CP responds to
all DNS requests listing the address of its web portal. Once the all DNS requests listing the address of its web portal. Once the
user has authenticated the CP returns the "correct" addresses. user has authenticated, the CP returns the "correct" addresses.
This technique has many shortcomings. It fails if the client is This technique has many shortcomings. It fails if the client is
performing DNSSEC validation, is running their own resolver, is using performing DNSSEC validation, is running their own resolver, is using
a VPN, or already has the DNS information cached. a VPN, or already has the DNS information cached.
2.2. HTTP Redirection 2.2. HTTP Redirection
In this implementation, the CP acts like a transparent HTTP proxy; In this implementation, the CP acts like a transparent HTTP proxy;
but when it sees an HTTP request from an unauthenticated client using but when it sees an HTTP request from an unauthenticated client using
HTTP/1.0, it intercepts the request and responds with an HTTP status HTTP/1.0, it intercepts the request and responds with an HTTP status
skipping to change at page 5, line 15 skipping to change at page 4, line 46
2.3. IP Hijacking 2.3. IP Hijacking
In this scenario, the captive portal intercepts connections to any IP In this scenario, the captive portal intercepts connections to any IP
address. It spoofs the destination IP address and "pretends" to be address. It spoofs the destination IP address and "pretends" to be
whatever the user tried to access. whatever the user tried to access.
This technique has issues similar to the HTTP solution, but may also This technique has issues similar to the HTTP solution, but may also
break other protocols, and may expose more of the user's private break other protocols, and may expose more of the user's private
information. information.
3. The Captive-Portal DHCP Option 3. The Captive-Portal IPv4 DHCP Option
The Captive Portal DHCP Option (TBA1) informs the DHCP client that it The Captive Portal DHCP Option (TBA1) informs an IPv4 client that it
is behind a captive portal and provides the URI to access an is behind a captive portal and provides the URI to access an
authentication page. This is primarily intended to improve the user authentication page. This is primarily intended to improve the user
experience; for the foreseeable future (until such time that most experience; for the foreseeable future (until such time that most
systems implement this technique) captive portals will still need to systems implement this technique) captive portals will still need to
implement the interception techniques to serve legacy clients. implement the interception techniques to serve legacy clients.
The format of the DHCP Captive-Portal DHCP option is shown below. The format of the DHCP Captive-Portal DHCP option is shown below.
Code Len Data Code Len Data
+------+------+------+------+------+-- --+-----+ +------+------+------+------+------+-- --+-----+
| code | len | URI ... | | code | len | URI ... |
+------+------+------+------+------+-- --+-----+ +------+------+------+------+------+-- --+-----+
o Code: The Captive-Portal DHCP Option (TBA1 for DHCPv4, TBA2 for o Code: The Captive-Portal DHCP Option (TBA1)
DHCPv6)
o Len: The length, in octets of the URI. o Len: The length, in octets of the URI.
o URI: The URI of the authentication page that the user should o URI: The URI of the authentication page that the user should
connect to. connect to.
The URI MUST NOT contain a DNS name, in order to not require the CP In order to avoid having to perform DNS interception, the URI SHOULD
to access DNS queries from an unauthenticated user. Rather, if IPv4 contain an IPv4 address literal.
is supported in the network, one option's URI MUST contain an IPv4
address literal, and if IPv6 is supported in the network, one
option's URI MUST contain an IPv6 address literal. Note that this
implies that a dual stack network would include two such options in
its DHCP reply or RA.
In many cases, a CP would like to collect billing infomation (for
example, credit card information), and will want to do this over SSL/
TLS. In order to make this work, the web server on the IP literal
can redirect to a URI containing a DNS name. The CP implementor/
operator will need to ensure that the client machine can access this
URI and all service needed to make that work (for example, DNS,
etc.). In this case, the operator/implementor will potentially need
to deal with issues such as DNS tunnelling.
Captive Portals are free to serve a HTTP redirect on this address to For cases requiring SSL/TLS (collection of billing information for
a DNS name (for example, so they can provide a TLS protected web page example), the IP literal can redirect to a URI containing a DNS name.
for credit card information). This will require that the client be
able to perform DNS requests.
[ED NOTE: Using an address literal is less than ideal, but better [ED NOTE: Using an address literal is less than ideal, but better
than the alternatives. Recommending a DNS name means that the CP than the alternatives. Recommending a DNS name means that the CP
would need to allow DNS from unauthenticated clients (as we don't would need to allow DNS from unauthenticated clients (as we don't
want to force users to use the CP's provided DNS) and some users want to force users to use the CP's provided DNS) and some users
would use this to DNS Tunnel out. This would make the CP admin block would use this to DNS Tunnel out. This would make the CP admin block
external recursives).] external recursives).]
4. The Captive-Portal RA Option 4. The Captive-Portal IPv6 RA Option
[Ed: I'm far from an RA expert. I think there are only 8 bits for
Type, is it worth burning an option code on this? I have also
specified that the option length should padded to multiples of 8 byte
to better align with the examples I've seen. Is this required /
preferred, or is smaller RAs better? ]
This section describes the Captive-Portal Router Advertisement This section describes the Captive-Portal Router Advertisement
option. option.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | URI . | Type | Length | URI .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ .
. . . .
. . . .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Captive-Portal RA Option Format Figure 2: Captive-Portal RA Option Format
Type TBA3 Type TBA2
Length 8-bit unsigned integer. The length of the option (including Length 8-bit unsigned integer. The length of the option (including
the Type and Length fields) in units of 8 bytes. the Type and Length fields) in units of 8 bytes.
URI The URI (containing an IPv6 literal) of the authentication page URI The URI of the authentication page that the user should connect
that the user should connect to. This should be padded with NULL to. For the reasons described above, the implementer might want
(0x0) to make the total option length (including the Type and to use an IP address literal instead of a DNS name. This should
Length fields) a multiple of 8 bytes. be padded with NULL (0x0) to make the total option length
(including the Type and Length fields) a multiple of 8 bytes.
5. Use of the Captive-Portal Option 5. Use of the Captive-Portal Option
[ED NOTE: This option provides notice to the OS / User applications [ED NOTE: This option provides notice to the OS / User applications
that there is a CP. Because of differences in UI design between that there is a CP. Because of differences in UI design between
Operating Systems, the exact behaviour by OS and Applications is left Operating Systems, the exact behaviour by OS and Applications is left
to the OS vendor/Application Developer.] to the OS vendor/Application Developer.]
The purpose of the Captive-Portal Option is to inform the operating The purpose of the Captive-Portal Option is to inform the operating
system and applications that they are behind a captive portal type system and applications that they are behind a captive portal type
device and will need to authenticate before getting network access device and will need to authenticate before getting network access
(and how to reach the authentication page). What is done with this (and how to reach the authentication page). What is done with this
information is left up to the operating system and application information is left up to the operating system and application
vendors. This document provides a very high level example of what vendors. This document provides a very high level example of what
could be done with this information. could be done with this information.
Many operating systems / applications already include a "connectivity Many operating systems / applications already include a "connectivity
test" to determine if they are behind a captive portal (for example, test" to determine if they are behind a captive portal (for example,
attempting to fetch a specific URL and looking for a specific string attempting to fetch a specific URL and looking for a specific string
(such as "Success")). These tests sometimes fail or take a long time (such as "Success"). These tests sometimes fail or take a long time
to determine when they are behind a CP, but are usually effective for to determine when they are behind a CP, but are usually effective for
determining that the captive portal has been satisfied. These tests determining that the captive portal has been satisfied. These tests
will continue to be needed, because there is currently no definitive will continue to be needed, because there is currently no definitive
signal from the captive portal that it has been satisfied. [ Editor signal from the captive portal that it has been satisfied. [ Editor
note: It may be useful to write another document that specifies how a note: It may be useful to write another document that specifies how a
client can determine that it has passed the CP. This document could client can determine that it has passed the CP. This document could
also contain advice to implmentors on only intercepting actually also contain advice to implmentors on only intercepting actually
needed ports, how to advertise that the CP needs to be statisfied needed ports, how to advertise that the CP needs to be statisfied
*again*, etc. This should not be done in this document though. ] The *again*, etc. This should not be done in this document though. ] The
connectivity test may also need to be used if the captive portal connectivity test may also need to be used if the captive portal
times out the user session and needs the user to re-authenticate / times out the user session and needs the user to re-authenticate.
pay again. The operating system may still find the information about The operating system may still find the information about the captive
the captive portal URI useful in this case. portal URI useful in this case.
When the device is informed that it is behind a captive portal it When the device is informed that it is behind a captive portal it
SHOULD: should:
1. Not initiate new IP connections until the CP has been satisfied 1. Not initiate new IP connections until the CP has been satisfied
(other than those to the captive portal browser session and (other than those to the captive portal browser session and
connectivity checks). Existing connections should be quiesced connectivity checks). Existing connections should be quiesced
(this will happen more often than some expect -- for example, the (this will happen more often than some expect -- for example, the
user purchases 1 hour of Internet at a cafe and stays there for 3 user purchases 1 hour of Internet at a cafe and stays there for 3
hours -- this will "interrupt" the user a few times). hours -- this will "interrupt" the user a few times).
2. Present a dialog box to the user informing them that they are 2. Present a dialog box to the user informing them that they are
behind a captive portal and ask if they wish to proceed. behind a captive portal and ask if they wish to proceed.
skipping to change at page 8, line 26 skipping to change at page 7, line 35
5. The device should (using an OS dependent method) expose to the 5. The device should (using an OS dependent method) expose to the
user / user applications that they have connected though a user / user applications that they have connected though a
captive portal (for example by creating a file in /proc/net/ captive portal (for example by creating a file in /proc/net/
containing the interface and captive portal URI). This should containing the interface and captive portal URI). This should
continue until the network changes, or a new DHCP message without continue until the network changes, or a new DHCP message without
the CP is received. the CP is received.
6. IANA Considerations 6. IANA Considerations
This document defines DHCPv4 Captive-Portal option which requires This document defines the DHCP Captive-Portal option and requires
assignment of DHCPv4 option code TBA1 assigned from "Bootp and DHCP assignment of an option code (TBA1) to be assigned from "Bootp and
options" registry (http://www.iana.org/assignments/ bootp-dhcp- DHCP options" registry (http://www.iana.org/assignments/ bootp-dhcp-
parameters/bootp-dhcp-parameters.xml), as specified in [RFC2939]. parameters/bootp-dhcp-parameters.xml), as specified in [RFC2939].
IANA is also requested to assign an IPv6 RA Option Type code (TBA3) IANA is also requested to assign an IPv6 RA Option Type code (TBA2)
from the "IPv6 Neighbor Discovery Option Formats" registry. Thanks from the "IPv6 Neighbor Discovery Option Formats" registry. Thanks
IANA! IANA!
7. Security Considerations 7. Security Considerations
An attacker with the ability to inject DHCP messages could include An attacker with the ability to inject DHCP messages could include
this option and so force users to contact an address of his choosing. this option and so force users to contact an address of his choosing.
As an attacker with this capability could simply list himself as the As an attacker with this capability could simply list himself as the
default gateway (and so intercept all the victim's traffic), this default gateway (and so intercept all the victim's traffic), this
does not provide them with significantly more capabilities. Fake does not provide them with significantly more capabilities. Fake
skipping to change at page 9, line 16 skipping to change at page 8, line 25
doing away with the need for interception, we think that users will doing away with the need for interception, we think that users will
be less likely to disable useful security safeguards like DNSSEC be less likely to disable useful security safeguards like DNSSEC
validation, VPNs, etc. In addition, because the system knows that it validation, VPNs, etc. In addition, because the system knows that it
is behind a captive portal, it can know not to send cookies, is behind a captive portal, it can know not to send cookies,
credentials, etc. Redirection to a portal where TLS can be used credentials, etc. Redirection to a portal where TLS can be used
without hijacking can ameliorate some of the implications of without hijacking can ameliorate some of the implications of
connecting to a potentially malicious captive portal. connecting to a potentially malicious captive portal.
8. Acknowledgements 8. Acknowledgements
The primary author has discussed this idea with a number of folk, and
asked them to assist by becoming co-authors. Unfortunately he has
forgotten who many of them were; if you were one of them, I
apologize.
Thanks to Vint Cerf for the initial idea / asking me to write this. Thanks to Vint Cerf for the initial idea / asking me to write this.
Thanks to Wes George for supplying the IPv6 text. Thanks to Lorenzo Thanks to Wes George for supplying the IPv6 text. Thanks to Lorenzo
and Erik for the V6 RA kick in the pants. and Erik for the V6 RA kick in the pants.
Thanks to Fred Baker and Asbjorn Tonnesen for detailed review and Thanks to Fred Baker, Ted Lemon, Ole Troan and Asbjorn Tonnesen for
comments. Also great thanks to Joel Jaeggli for providing feedback detailed review and comments. Also great thanks to Joel Jaeggli for
and text. providing feedback and text.
9. Normative References 9. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
Appendix A. Changes / Author Notes. Appendix A. Changes / Author Notes.
[RFC Editor: Please remove this section before publication ] [RFC Editor: Please remove this section before publication ]
From 07 to 08:
o Incorporated comments from Ted Lemon. Made the document much
shorter.
o Some cleanup.
From 06 to 07: From 06 to 07:
o Incoroprated a bunch of comments from Asbjorn Tonnesen o Incoroprated a bunch of comments from Asbjorn Tonnesen
o Clarified that this document is only for the DHCP bits, not o Clarified that this document is only for the DHCP bits, not
everything. everything.
o CP's *can* do HTTP redirects to DNS banes, as long as they allow o CP's *can* do HTTP redirects to DNS banes, as long as they allow
access to all needed services. access to all needed services.
From 05 to 06: From 05 to 06:
o Integrated comments from Joel, as below o Integrated comments from Joel, as below
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