draft-ietf-dnsop-edns-tcp-keepalive-03.txt   draft-ietf-dnsop-edns-tcp-keepalive-04.txt 
dnsop P. Wouters dnsop P. Wouters
Internet-Draft Red Hat Internet-Draft Red Hat
Intended status: Standards Track J. Abley Intended status: Standards Track J. Abley
Expires: April 2, 2016 Dyn, Inc. Expires: April 22, 2016 Dyn, Inc.
S. Dickinson S. Dickinson
Sinodun Sinodun
R. Bellis R. Bellis
ISC ISC
September 30, 2015 October 20, 2015
The edns-tcp-keepalive EDNS0 Option The edns-tcp-keepalive EDNS0 Option
draft-ietf-dnsop-edns-tcp-keepalive-03 draft-ietf-dnsop-edns-tcp-keepalive-04
Abstract Abstract
DNS messages between clients and servers may be received over either DNS messages between clients and servers may be received over either
UDP or TCP. UDP transport involves keeping less state on a busy UDP or TCP. UDP transport involves keeping less state on a busy
server, but can cause truncation and retries over TCP. Additionally, server, but can cause truncation and retries over TCP. Additionally,
UDP can be exploited for reflection attacks. Using TCP would reduce UDP can be exploited for reflection attacks. Using TCP would reduce
retransmits and amplification. However, clients commonly use TCP retransmits and amplification. However, clients commonly use TCP
only for fallback and servers typically use idle timeouts on the only for fallback and servers typically use idle timeouts on the
order of seconds. order of seconds.
skipping to change at page 1, line 49 skipping to change at page 1, line 49
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
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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 April 2, 2016. This Internet-Draft will expire on April 22, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 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.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 4 2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 4
3. The edns-tcp-keepalive Option . . . . . . . . . . . . . . . . 4 3. The edns-tcp-keepalive Option . . . . . . . . . . . . . . . . 5
3.1. Option Format . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Option Format . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Use by DNS Clients . . . . . . . . . . . . . . . . . . . 5 3.2. Use by DNS Clients . . . . . . . . . . . . . . . . . . . 6
3.2.1. Sending Queries . . . . . . . . . . . . . . . . . . . 5 3.2.1. Sending Queries . . . . . . . . . . . . . . . . . . . 6
3.2.2. Receiving Responses . . . . . . . . . . . . . . . . . 6 3.2.2. Receiving Responses . . . . . . . . . . . . . . . . . 6
3.3. Use by DNS Servers . . . . . . . . . . . . . . . . . . . 6 3.3. Use by DNS Servers . . . . . . . . . . . . . . . . . . . 6
3.3.1. Receiving Queries . . . . . . . . . . . . . . . . . . 6 3.3.1. Receiving Queries . . . . . . . . . . . . . . . . . . 6
3.3.2. Sending Responses . . . . . . . . . . . . . . . . . . 6 3.3.2. Sending Responses . . . . . . . . . . . . . . . . . . 7
3.4. TCP Session Management . . . . . . . . . . . . . . . . . 7 3.4. TCP Session Management . . . . . . . . . . . . . . . . . 7
3.5. Non-Clean Paths . . . . . . . . . . . . . . . . . . . . . 8 3.5. Non-Clean Paths . . . . . . . . . . . . . . . . . . . . . 8
3.6. Anycast Considerations . . . . . . . . . . . . . . . . . 8 3.6. Anycast Considerations . . . . . . . . . . . . . . . . . 8
4. Intermediary Considerations . . . . . . . . . . . . . . . . . 8 4. Intermediary Considerations . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.1. Normative References . . . . . . . . . . . . . . . . . . 9 8.1. Normative References . . . . . . . . . . . . . . . . . . 9
8.2. Informative References . . . . . . . . . . . . . . . . . 10 8.2. Informative References . . . . . . . . . . . . . . . . . 10
Appendix A. Editors' Notes . . . . . . . . . . . . . . . . . . . 10 Appendix A. Editors' Notes . . . . . . . . . . . . . . . . . . . 11
A.1. Abridged Change History . . . . . . . . . . . . . . . . . 10 A.1. Abridged Change History . . . . . . . . . . . . . . . . . 11
A.1.1. draft-ietf-dnsop-edns-tcp-keepalive-03 . . . . . . . 10 A.1.1. draft-ietf-dnsop-edns-tcp-keepalive-04 . . . . . . . 11
A.1.2. draft-ietf-dnsop-edns-tcp-keepalive-02 . . . . . . . 11 A.1.2. draft-ietf-dnsop-edns-tcp-keepalive-03 . . . . . . . 11
A.1.3. draft-ietf-dnsop-edns-tcp-keepalive-01 . . . . . . . 11 A.1.3. draft-ietf-dnsop-edns-tcp-keepalive-02 . . . . . . . 12
A.1.4. draft-ietf-dnsop-edns-tcp-keepalive-00 . . . . . . . 11 A.1.4. draft-ietf-dnsop-edns-tcp-keepalive-01 . . . . . . . 12
A.1.5. draft-wouters-edns-tcp-keepalive-01 . . . . . . . . . 12 A.1.5. draft-ietf-dnsop-edns-tcp-keepalive-00 . . . . . . . 12
A.1.6. draft-wouters-edns-tcp-keepalive-00 . . . . . . . . . 12 A.1.6. draft-wouters-edns-tcp-keepalive-01 . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 A.1.7. draft-wouters-edns-tcp-keepalive-00 . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
DNS messages between clients and servers may be received over either DNS messages between clients and servers may be received over either
UDP or TCP [RFC1035]. Historically, DNS clients used API's that only UDP or TCP [RFC1035]. Historically, DNS clients used API's that only
facilitated sending and receiving a single query over either UDP or facilitated sending and receiving a single query over either UDP or
TCP. New APIs and deployment of DNSSEC validating resolvers on hosts TCP. New APIs and deployment of DNSSEC validating resolvers on hosts
that in the past were using stub resolving only is increasing the DNS that in the past were using stub resolving only is increasing the DNS
client base that prefer using long lived TCP connections. Long-lived client base that prefer using long lived TCP connections. Long-lived
TCP connections can result in lower request latency than the case TCP connections can result in lower request latency than the case
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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
+-------------------------------+-------------------------------+ +-------------------------------+-------------------------------+
! OPTION-CODE ! OPTION-LENGTH ! ! OPTION-CODE ! OPTION-LENGTH !
+-------------------------------+-------------------------------+ +-------------------------------+-------------------------------+
| TIMEOUT ! | TIMEOUT !
+-------------------------------+ +-------------------------------+
where: where:
OPTION-CODE: the EDNS0 option code assigned to edns-tcp-keepalive, OPTION-CODE: the EDNS0 option code assigned to edns-tcp-keepalive,
[TBD] TBD1
OPTION-LENGTH: the value 0 if the TIMEOUT is omitted, the value 2 OPTION-LENGTH: the value 0 if the TIMEOUT is omitted, the value 2
if it is present; if it is present;
TIMEOUT: an idle timeout value for the TCP connection, specified in TIMEOUT: an idle timeout value for the TCP connection, specified in
units of 100 milliseconds, encoded in network byte order. units of 100 milliseconds, encoded in network byte order.
3.2. Use by DNS Clients 3.2. Use by DNS Clients
3.2.1. Sending Queries 3.2.1. Sending Queries
DNS clients MUST NOT include the edns-tcp-keepalive option in queries DNS clients MUST NOT include the edns-tcp-keepalive option in queries
sent using UDP transport. sent using UDP transport.
DNS clients MAY include the edns-tcp-keepalive option in the first DNS clients MAY include the edns-tcp-keepalive option in the first
query sent to a server using TCP transport to signal their desire to query sent to a server using TCP transport to signal their desire to
keep the connection open when idle. keep the connection open when idle.
DNS clients MAY include the edns-tcp-keepalive option in subsequent
queries sent to a server using TCP transport to signal their
continued desire to keep the connection open when idle.
Clients MUST specify an OPTION-LENGTH of 0 and omit the TIMEOUT Clients MUST specify an OPTION-LENGTH of 0 and omit the TIMEOUT
value. value.
3.2.2. Receiving Responses 3.2.2. Receiving Responses
A DNS client that receives a response using UDP transport that A DNS client that receives a response using UDP transport that
includes the edns-tcp-keepalive option MUST ignore the option. includes the edns-tcp-keepalive option MUST ignore the option.
A DNS client that receives a response using TCP transport that A DNS client that receives a response using TCP transport that
includes the edns-tcp-keepalive option MAY keep the existing TCP includes the edns-tcp-keepalive option MAY keep the existing TCP
session open when it is idle. It SHOULD honour the timeout and session open when it is idle. It SHOULD honour the timeout and
initiate close of the connection before the timeout expires. initiate close of the connection before the timeout expires.
A DNS client that receives a response that includes the edns-tcp- A DNS client that receives a response that includes the edns-tcp-
keepalive option with a TIMEOUT value of 0 should send no more keepalive option with a TIMEOUT value of 0 SHOULD send no more
queries on that connection and initiate closing the connection as queries on that connection and initiate closing the connection as
soon as it has received all outstanding responses. soon as it has received all outstanding responses.
A DNS client that sent a query containing the edns-keepalive-option A DNS client that sent a query containing the edns-keepalive-option
but receives a response that does not contain the edns-keepalive- but receives a response that does not contain the edns-keepalive-
option should assume the server does not support keepalive and behave option should assume the server does not support keepalive and behave
following the guidance in [DRAFT-5966bis]. This holds true even if a following the guidance in [DRAFT-5966bis]. This holds true even if a
previous edns-keepalive-option exchange occurred on the existing TCP previous edns-keepalive-option exchange occurred on the existing TCP
connection. connection.
skipping to change at page 8, line 16 skipping to change at page 8, line 18
persistent TCP connection it means that (following the initial persistent TCP connection it means that (following the initial
exchange of timeouts) a server may not be presented with the exchange of timeouts) a server may not be presented with the
opportunity to signal a change in the idle timeout associated with a opportunity to signal a change in the idle timeout associated with a
connection if the client does not send any further requests connection if the client does not send any further requests
containing EDNS0 OPT RRs. This limitation makes persistent containing EDNS0 OPT RRs. This limitation makes persistent
connection handling via an initial idle timeout signal more connection handling via an initial idle timeout signal more
attractive than a mechanism that establishes default persistence and attractive than a mechanism that establishes default persistence and
then uses a connection close signal (in a similar manner to HTTP 1.1 then uses a connection close signal (in a similar manner to HTTP 1.1
[RFC7320]). [RFC7320]).
If a client includes the edns-tcp-keepalive option in the first
query, it SHOULD include an EDNS0 OPT RR periodically in any further
messages it sends during the TCP session. This will increase the
chance of the client being notified should the server modify the
timeout associated with a session. The algorithm for choosing when
to do this is out of scope of this document and is left up to the
implementor and/or operator.
DNS clients and servers MAY close a TCP session at any time in order DNS clients and servers MAY close a TCP session at any time in order
to manage local resource constraints. The algorithm by which clients to manage local resource constraints. The algorithm by which clients
and servers rank active TCP sessions in order to determine which to and servers rank active TCP sessions in order to determine which to
close is not specified in this document. close is not specified in this document.
3.5. Non-Clean Paths 3.5. Non-Clean Paths
Many paths between DNS clients and servers suffer from poor hygiene, Many paths between DNS clients and servers suffer from poor hygiene,
limiting the free flow of DNS messages that include particular EDNS0 limiting the free flow of DNS messages that include particular EDNS0
options, or messages that exceed a particular size. A fallback options, or messages that exceed a particular size. A fallback
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4. Intermediary Considerations 4. Intermediary Considerations
It is RECOMMENDED that DNS intermediaries which terminate TCP It is RECOMMENDED that DNS intermediaries which terminate TCP
connections implement edns-tcp-keepalive. An intermediary that does connections implement edns-tcp-keepalive. An intermediary that does
not implement edns-tcp-keepalive but sits between a client and server not implement edns-tcp-keepalive but sits between a client and server
that both support edns-tcp-keepalive might close idle connections that both support edns-tcp-keepalive might close idle connections
unnecessarily. unnecessarily.
5. Security Considerations 5. Security Considerations
The edns-tcp-keepalive option can potentially be abused to request The edns-tcp-keepalive option can potentially be abused to request
large numbers of sessions in a quick burst. When a Nameserver large numbers of sessions in a quick burst. When a DNS Server
detects abusive behaviour, it SHOULD immediately close the TCP detects abusive behaviour, it SHOULD immediately close the TCP
connection and free the resources used. connection and free the resources used.
Servers could choose to monitor client behaviour with respect to the Servers could choose to monitor client behaviour with respect to the
edns-tcp-keepalive option to build up profiles of clients that do not edns-tcp-keepalive option to build up profiles of clients that do not
honour the specified timeout. honour the specified timeout.
Readers are advised to familiarise themselves with the security Readers are advised to familiarise themselves with the security
considerations outlined in [DRAFT-5966bis] considerations outlined in [DRAFT-5966bis]
6. IANA Considerations 6. IANA Considerations
The IANA is directed to assign an EDNS0 option code for the edns-tcp- The IANA is directed to assign an EDNS0 option code for the edns-tcp-
keepalive option from the DNS EDNS0 Option Codes (OPT) registry as keepalive option from the DNS EDNS0 Option Codes (OPT) registry as
follows: follows:
+-------+--------------------+----------+-----------------+ +-------+--------------------+----------+-----------------+
| Value | Name | Status | Reference | | Value | Name | Status | Reference |
+-------+--------------------+----------+-----------------+ +-------+--------------------+----------+-----------------+
| [TBA] | edns-tcp-keepalive | Optional | [This document] | | TBD1 | edns-tcp-keepalive | Optional | [This document] |
+-------+--------------------+----------+-----------------+ +-------+--------------------+----------+-----------------+
7. Acknowledgements 7. Acknowledgements
The authors acknowledge the contributions of Jinmei TATUYA and Mark The authors acknowledge the contributions of Jinmei TATUYA and Mark
Andrews. Thanks to Duane Wessels for detailed review and the many Andrews. Thanks to Duane Wessels for detailed review and the many
others who contributed to the mailing list discussion. others who contributed to the mailing list discussion.
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC1035] Mockapetris, P., "Domain names - implementation and [RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, <http://www.rfc-editor.org/info/rfc1035>.
[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,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "DNS Security Introduction and Requirements", RFC Rose, "DNS Security Introduction and Requirements",
4033, March 2005. RFC 4033, DOI 10.17487/RFC4033, March 2005,
<http://www.rfc-editor.org/info/rfc4033>.
[RFC4786] Abley, J. and K. Lindqvist, "Operation of Anycast [RFC4786] Abley, J. and K. Lindqvist, "Operation of Anycast
Services", BCP 126, RFC 4786, December 2006. Services", BCP 126, RFC 4786, DOI 10.17487/RFC4786,
December 2006, <http://www.rfc-editor.org/info/rfc4786>.
[RFC5966] Bellis, R., "DNS Transport over TCP - Implementation
Requirements", RFC 5966, August 2010.
[RFC6824] Ford, A., Raiciu, C., Handley, M., and O. Bonaventure,
"TCP Extensions for Multipath Operation with Multiple
Addresses", RFC 6824, January 2013.
[RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms [RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms
for DNS (EDNS(0))", STD 75, RFC 6891, April 2013. for DNS (EDNS(0))", STD 75, RFC 6891,
DOI 10.17487/RFC6891, April 2013,
<http://www.rfc-editor.org/info/rfc6891>.
[RFC7320] Nottingham, M., "URI Design and Ownership", BCP 190, RFC [RFC7320] Nottingham, M., "URI Design and Ownership", BCP 190,
7320, July 2014. RFC 7320, DOI 10.17487/RFC7320, July 2014,
<http://www.rfc-editor.org/info/rfc7320>.
8.2. Informative References 8.2. Informative References
[CHAIN-QUERY] [CHAIN-QUERY]
Wouters, P., "Chain Query requests in DNS", draft-ietf- Wouters, P., "Chain Query requests in DNS", draft-ietf-
dnsop-edns-chain-query (work in progress), March 2015. dnsop-edns-chain-query (work in progress), October 2015.
[DNS-over-TLS] [DNS-over-TLS]
Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
and P. Hoffman, "TLS for DNS: Initiation and Performance and P. Hoffman, "TLS for DNS: Initiation and Performance
Considerations", draft-ietf-dprive-dns-over-tls-00 (work Considerations", draft-ietf-dprive-dns-over-tls-01 (work
in progress), September 2015. in progress), October 2015.
[DRAFT-5966bis] [DRAFT-5966bis]
Dickinson, J., Dickinson, S., Bellis, R., Mankin, A., and Dickinson, J., Dickinson, S., Bellis, R., Mankin, A., and
D. Wessels, "DNS Transport over TCP - Implementation D. Wessels, "DNS Transport over TCP - Implementation
Requirements", draft-ietf-dnsop-5966bis-03 (work in Requirements", draft-ietf-dnsop-5966bis-03 (work in
progress), September 2015. progress), September 2015.
[RRL] Vixie, P. and V. Schryver, "DNS Response Rate Limiting
(DNS RRL)", ISC-TN 2012-1-Draft1, April 2012.
[fragmentation-considered-poisonous] [fragmentation-considered-poisonous]
Herzberg, A. and H. Shulman, "Fragmentation Considered Herzberg, A. and H. Shulman, "Fragmentation Considered
Poisonous", arXiv 1205.4011, May 2012. Poisonous", arXiv 1205.4011, May 2012.
[RFC6824] Ford, A., Raiciu, C., Handley, M., and O. Bonaventure,
"TCP Extensions for Multipath Operation with Multiple
Addresses", RFC 6824, DOI 10.17487/RFC6824, January 2013,
<http://www.rfc-editor.org/info/rfc6824>.
[RRL] Vixie, P. and V. Schryver, "DNS Response Rate Limiting
(DNS RRL)", ISC-TN 2012-1-Draft1, April 2012.
Appendix A. Editors' Notes Appendix A. Editors' Notes
A.1. Abridged Change History A.1. Abridged Change History
A.1.1. draft-ietf-dnsop-edns-tcp-keepalive-03 [Note to RFC Editor: please remove this section prior to
publication.]
A.1.1. draft-ietf-dnsop-edns-tcp-keepalive-04
Adding wording to sections 3.2.1 and 3.4 to clarify client behaviour
on subsequent queries on a TCP connection.
Changed the should to a SHOULD in section 3.2.2
Changed Nameserver to DNS server in section 5.
Updated references.
Changed reference to RFC6824 to be informative.
Corrected reference to requested EDNS0 option code to be 'TBD1'.
A.1.2. draft-ietf-dnsop-edns-tcp-keepalive-03
Clarified that a response to a query with any OPT RR may contain the Clarified that a response to a query with any OPT RR may contain the
ends-tcp-keepalive option. ends-tcp-keepalive option.
Corrected TIMEOUT length from 4 to 2 in the diagram. Corrected TIMEOUT length from 4 to 2 in the diagram.
Updated references, including name change of [STARTTLS] -> [DNS-over- Updated references, including name change of STARTTLS -> DNS-over-TLS
TLS] and adding reference for cache poisoning. and adding reference for cache poisoning.
Updated wording in section on Intermediary Considerations. Updated wording in section on Intermediary Considerations.
Updated wording describing RRL. Updated wording describing RRL.
Added paragraph to security section describing client behaviour Added paragraph to security section describing client behaviour
profiles. profiles.
Added wording to introduction on use case for stub/resolver/ Added wording to introduction on use case for stub/resolver/
authoritative. authoritative.
A.1.2. draft-ietf-dnsop-edns-tcp-keepalive-02 A.1.3. draft-ietf-dnsop-edns-tcp-keepalive-02
Changed timeout value to idle timeout and re-phrased document around Changed timeout value to idle timeout and re-phrased document around
this. this.
Changed units of timeout to 100ms to allow values less than 1 second. Changed units of timeout to 100ms to allow values less than 1 second.
Change specification to remove use of the option over UDP. This is Change specification to remove use of the option over UDP. This is
potentially confusing, could cause issues with ALG's and adds only potentially confusing, could cause issues with ALG's and adds only
limited value. limited value.
skipping to change at page 11, line 47 skipping to change at page 12, line 37
distinct 'connection close'-like signal is potentially more useful. distinct 'connection close'-like signal is potentially more useful.
Added more detail on server side requirements when supporting Added more detail on server side requirements when supporting
keepalive in terms of resource and connection management. keepalive in terms of resource and connection management.
Added discussion of EDNS0 per-message limitation and implications of Added discussion of EDNS0 per-message limitation and implications of
this. this.
Added reference to STARTTLS draft and RFC7320. Added reference to STARTTLS draft and RFC7320.
A.1.3. draft-ietf-dnsop-edns-tcp-keepalive-01 A.1.4. draft-ietf-dnsop-edns-tcp-keepalive-01
Version bump with no changes Version bump with no changes
A.1.4. draft-ietf-dnsop-edns-tcp-keepalive-00 A.1.5. draft-ietf-dnsop-edns-tcp-keepalive-00
Clarifications, working group adoption. Clarifications, working group adoption.
A.1.5. draft-wouters-edns-tcp-keepalive-01 A.1.6. draft-wouters-edns-tcp-keepalive-01
Also allow clients to specify KEEPALIVE timeout values, clarify Also allow clients to specify KEEPALIVE timeout values, clarify
motivation of document. motivation of document.
A.1.6. draft-wouters-edns-tcp-keepalive-00 A.1.7. draft-wouters-edns-tcp-keepalive-00
Initial draft. Initial draft.
Authors' Addresses Authors' Addresses
Paul Wouters Paul Wouters
Red Hat Red Hat
Email: pwouters@redhat.com Email: pwouters@redhat.com
 End of changes. 33 change blocks. 
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