Re: [MMUSIC] Continued WG interest in SDP offer/answer with middleboxes?

"Dan Wing" <dwing@cisco.com> Tue, 15 March 2011 16:52 UTC

Return-Path: <dwing@cisco.com>
X-Original-To: mmusic@core3.amsl.com
Delivered-To: mmusic@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 2FEA13A6E1C for <mmusic@core3.amsl.com>; Tue, 15 Mar 2011 09:52:11 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -105.317
X-Spam-Level:
X-Spam-Status: No, score=-105.317 tagged_above=-999 required=5 tests=[AWL=-4.915, BAYES_00=-2.599, FRT_POSSIBLE=2.697, J_CHICKENPOX_31=0.6, MANGLED_FROM=2.3, MANGLED_LOOK=2.3, MANGLED_WORKS=2.3, RCVD_IN_DNSWL_HI=-8, USER_IN_WHITELIST=-100]
Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id QadshIW0E84u for <mmusic@core3.amsl.com>; Tue, 15 Mar 2011 09:52:06 -0700 (PDT)
Received: from sj-iport-5.cisco.com (sj-iport-5.cisco.com [171.68.10.87]) by core3.amsl.com (Postfix) with ESMTP id 4C7D83A6C5B for <mmusic@ietf.org>; Tue, 15 Mar 2011 09:52:05 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=dwing@cisco.com; l=48119; q=dns/txt; s=iport; t=1300208011; x=1301417611; h=from:to:references:in-reply-to:subject:date:message-id: mime-version:content-transfer-encoding; bh=YtJTrkkfFIXlCL7C+ud8abfOAVIhzr7oN4WD8EsH/w8=; b=nBRaF5zjpUs/ph16Jbg7IZu8qTDXXFJrYkvWG/xSOYXOgNALj04teYc9 crBjiGkpAxmYlD34VkGRgJVtdMRySXvSMXK3i4A3Py6ioF0zY8axvthFb BiDK/s40p7LP5YBPbXKVUe38Rn22BCXDcmDMlvmUwQHTTYYNg90oPLnhi 8=;
X-IronPort-AV: E=Sophos;i="4.63,188,1299456000"; d="scan'208";a="347139568"
Received: from rcdn-core2-4.cisco.com ([173.37.113.191]) by sj-iport-5.cisco.com with ESMTP; 15 Mar 2011 16:53:26 +0000
Received: from dwingWS ([10.32.240.196]) by rcdn-core2-4.cisco.com (8.14.3/8.14.3) with ESMTP id p2FGrNXs020007; Tue, 15 Mar 2011 16:53:23 GMT
From: Dan Wing <dwing@cisco.com>
To: 'Christer Holmberg' <christer.holmberg@ericsson.com>, 'Flemming Andreasen' <fandreas@cisco.com>, 'mmusic' <mmusic@ietf.org>
References: <4D798594.4000406@cisco.com> <0ed601cbe2ba$1bdfd740$539f85c0$@com> <7F2072F1E0DE894DA4B517B93C6A05851948F0B315@ESESSCMS0356.eemea.ericsson.se>
In-Reply-To: <7F2072F1E0DE894DA4B517B93C6A05851948F0B315@ESESSCMS0356.eemea.ericsson.se>
Date: Tue, 15 Mar 2011 09:53:22 -0700
Message-ID: <11cc01cbe331$7f2d29c0$7d877d40$@com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
X-Mailer: Microsoft Office Outlook 12.0
Thread-Index: Acvfka8IjyVdSV50SF6vU/ruI/PbtgDJ16tgAAiwCIAAFTL8AA==
Content-language: en-us
Subject: Re: [MMUSIC] Continued WG interest in SDP offer/answer with middleboxes?
X-BeenThere: mmusic@ietf.org
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: Multiparty Multimedia Session Control Working Group <mmusic.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/listinfo/mmusic>, <mailto:mmusic-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/mmusic>
List-Post: <mailto:mmusic@ietf.org>
List-Help: <mailto:mmusic-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/mmusic>, <mailto:mmusic-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 15 Mar 2011 16:52:12 -0000

> -----Original Message-----
> From: mmusic-bounces@ietf.org [mailto:mmusic-bounces@ietf.org] On
> Behalf Of Christer Holmberg
> Sent: Monday, March 14, 2011 11:44 PM
> To: 'Dan Wing'; 'Flemming Andreasen'; 'mmusic'
> Subject: Re: [MMUSIC] Continued WG interest in SDP offer/answer with
> middleboxes?
> 
> 
> Hi Dan,
> 
> In my definition of an ALG packets can be sent directly to its IP
> address.

See below, where I searched for "ALG" in existing RFCs.  It seems
that "ALG" is pretty well entrenched to describe the operation in
a NAT or firewall, which does not have packets sent directly to
the IP address of the NAT or firewall.  RFC2101 is the first strong
definition, and used the term 'pure ALG' and 'transparent ALG'.
(I have not seen 'pure'/'transparent' used before I did this
grep through the RFCs, so I am not suggesting that this MMUSIC draft 
adopt that terminology.) 

> In my opinion, SIP B2BUA only focuses on SIP, while an ALG also focuses
> on other things, like media. A SIP ALG contains a SIP B2BUA.

But the draft already separates the two.  The draft currently says the 
SIP ALG only pertains to SIP, and a separate function ("middlebox") 
pertains to media.  See Figure 1 of
draft-ietf-mmusic-media-path-middleboxes-03 
which shows:


                     SIP     +-----------------+     SIP
         +-----+  Signaling  |     SIP ALG     |  Signaling  +-----+
         | UAC |<----------->+-----------------+<----------->| UAS |
         +-----+             |   MIDCOM Agent  |             +-----+
            ^                +-----------------+                ^
            |                         ^                         |
            |          Policy rule(s) | and NAT bindings        |
            |                         v                         |
            |      Media       +-------------+       Media      |
            +----------------->|  Middlebox  |<-----------------+
                               +-------------+

Changing "SIP ALG" in that diagram to "SIP B2BUA" would still fit
your definition.

-d

-----

grep "\bALG\b" rfc*.txt
rfc0759.txt:  14     ENCRYPT   CODE(1),COUNT(3),ALG-ID(1),
rfc1410.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423*
rfc1500.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc1540.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc1600.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc1610.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc1720.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc1780.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc1800.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc1880.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc1920.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc1991.txt:      0   2   RND(n bytes)   0  ALG(1 byte)  DEK(k bytes)
CSUM(2 by
tes)
rfc1991.txt:   ALG refers to the algorithm byte for the secret key algorithm
use
d to
rfc1991.txt:   ALG.  For the IDEA encryption algorithm, type byte 1, the DEK
is
16
rfc2000.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc2025.txt:2.1 Integrity Algorithm (I-ALG):
rfc2025.txt:2.2 Confidentiality Algorithm (C-ALG):
rfc2025.txt:2.3 Key Establishment Algorithm (K-ALG):
rfc2025.txt:         context.  The keys used for C-ALG and any keyed I-ALGs
(for

rfc2025.txt:            K-ALG cannot be used with unilateral authentication
in
rfc2025.txt:2.4 One-Way Function (O-ALG) for Subkey Derivation Algorithm:
rfc2025.txt:         Having established a context key using the negotiated
K-ALG
,
rfc2025.txt:         the longest key needed by any agreed C-ALG or keyed
I-ALG,
and
rfc2025.txt:         within the K-ALG parameters).
rfc2025.txt:         long.  If 512-bit RSAEncryption is the K-ALG in use
then th
e
rfc2025.txt:         the K-ALG in use then the context key is the result of
the
rfc2025.txt:         allowing negotiation of the O-ALG OWF during the
context
rfc2025.txt:   C-ALG over the established context, and the integrity
algorithms
rfc2025.txt:   selected by the target become ones that may be used for I-ALG
ove
r
rfc2025.txt:   list that it supports).  Note that any C-ALG and I-ALG may be
use
d
rfc2025.txt:   algorithm).  If this K-ALG is unacceptable to the target then
the

rfc2025.txt:   chooses a 2-pass K-ALG such as dhKeyAgreement), the initiator
wil
l
rfc2025.txt:   offers a set of possible O-ALGs (only a single O-ALG if no
respon
se
rfc2025.txt:   is expected).  The (single) O-ALG chosen by the target
becomes th
e
rfc2025.txt:   or all of I-ALG, C-ALG, K-ALG, and O-ALG.
rfc2025.txt:   unilateral authentication no negotiation of K-ALG can be done
(th
e
rfc2025.txt:   target either accepts the K-ALG and context key given by the
rfc2025.txt:   two-pass K-ALG offered by the initiator and, again, can be
reques
ted
rfc2025.txt:              -- key estb. parameter corresponding to first
K-ALG in
 set
rfc2025.txt:              -- unilateral authen. if the K-ALG in use does not
pro
vide
rfc2025.txt:              -- mandatory hashing procedure MD5 (in MANDATORY
I-ALG
;
rfc2025.txt:   } -- for C-ALG (see Section 5.2 for discussion of QOP)
rfc2025.txt:       -- for I-ALG (see Section 5.2 for discussion of QOP)
rfc2025.txt:       -- to allow negotiation of K-ALG
rfc2025.txt:             -- key-estb-req (if init. used a 2-pass K-ALG), or
(2)
the
rfc2025.txt:             -- key-estb-req corresponding to the K-ALG supplied
in
rfc2025.txt:             -- to the first K-ALG supplied in initiator's
key-estb-
id,
rfc2025.txt:                 -- (if target selected a 2-pass K-ALG)
rfc2025.txt:              -- unilateral authen. if the K-ALG in use does not
pro
vide
rfc2025.txt:              -- mandatory hashing procedure (in MANDATORY
I-ALG;
rfc2101.txt:      (ALG). Such a device acts as a termination point for the
rfc2101.txt:      to explicitly establish communication with the ALG that
rfc2101.txt:      ALG.
rfc2101.txt:      Another form of ALG makes communication through the ALG
rfc2101.txt:      "transparent" ALG, Ua would not be required to establish
expli
cit
rfc2101.txt:      connectivity to the ALG first, before starting to
communicate
with
rfc2101.txt:      communicating via an ALG involves changes to the network
heade
r.
rfc2101.txt:      An ALG could be used only at the beginning of a session
for th
e
rfc2101.txt:      purpose of authentication, after which the ALG goes away
and
rfc2101.txt:      described in RFC1631 is a device that has both the NAT and
ALG

rfc2101.txt:      a transparent ALG.
rfc2101.txt:      This is in contrast with an ALG that can support only the
rfc2101.txt:      applications coded into the ALG.
rfc2101.txt:      and ALG functionality in a single device could be used to
over
come
rfc2101.txt:      addresses, and would resort to the ALG functionality when
deal
ing
rfc2101.txt:      connection, but would use the ALG functionality to deal
with t
he
rfc2101.txt:      the device does not support the application via the ALG
rfc2101.txt:      communicating through either an ALG or a NAT. Since IP
Securit
y,
rfc2101.txt:      end-to-end, it is not clear how an ALG or NAT could modify
rfc2101.txt:      running a NAT or ALG probably needs to run two DNS
servers, on
e
rfc2101.txt:      inside and one outside the NAT or ALG, giving different
answer
s to
rfc2101.txt:      presumably not be valid across a NAT/ALG boundary, so we
must
rfc2154.txt:   SIG ALG         The signature algorithm for the Router Public
Key
.
rfc2182.txt:   an Application Layer Gateway (ALG).  Such a device would
understa
nd
rfc2182.txt:   of the firewall.  A server implemented in an ALG will usually
be
such
rfc2196.txt:   only subsections of the protocol.  For example, an ALG for
FTP ca
n
rfc2200.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc2300.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc2400.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers Elective
1
423
rfc2500.txt:PEM-ALG    PEM - Algorithms, Modes, and Identifiers
1
423
rfc2600.txt:PEM-ALG    Privacy Enhancement for Internet Electronic Mail
14
23
rfc2663.txt:   across realms, even with an ALG (defined below in section
2.9)
rfc2663.txt:2.9. Application Level gateway (ALG)
rfc2663.txt:   different realm transparently. An ALG may interact with NAT
to se
t up
rfc2663.txt:   address resolution. A DNS-ALG must be employed in conjunction
wit
h
rfc2663.txt:   Specifically, the DNS-ALG must be capable of translating
private
rfc2663.txt:   to Host-X, it issues a DNS query for Host-X. A DNS-ALG
intercepts
 the
rfc2663.txt:   DNS query, and in the response returned to Host-A the DNS-ALG
rfc2663.txt:   ALG modifies addresses (e.g., as in the case of Twice-NAT),
rfc2663.txt:   devoted to describing how FTP is supported on NAT devices.
FTP A
LG
rfc2663.txt:   response are an IP address and a TCP port in ASCII. An FTP
ALG is

rfc2663.txt:   The ALG must also update NAT with appropriate data session
tuples
 and
rfc2663.txt:   used by the ALG to correct the TCP sequence and acknowledge
numbe
rs.
rfc2663.txt:   not uncommon for an SNMP specific ALG to reside on a NAT
router t
o
rfc2663.txt:   to find NAT, ALG and firewall functions co-exist to provide
secur
ity
rfc2694.txt:   or indirectly (through the internal name servers). Using
DNS-ALG
rfc2694.txt:   headers of the DNS packet and notify DNS-ALG to perform DNS
paylo
ad
rfc2694.txt:   changes. DNS-ALG would interact with NAT and use NAT state
rfc2694.txt:    Figure 2: NAT & DNS-ALG in the translation path of DNS
packets
rfc2694.txt:   ALG implementations. Note, it is possible for a committed
address

rfc2694.txt:   is 198.76.29.1. DNS-ALG would use this temporary binding to
modif
y
rfc2694.txt:4. DNS payload modifications by DNS-ALG
rfc2694.txt:   headers of a DNS packet, DNS-ALG is responsible for updating
the
DNS
rfc2694.txt:   response. No changes are required to be made by DNS-ALG to
the He
ader
rfc2694.txt:   within the zone without intervention from NAT and DNS-ALG, so
lon
g as
rfc2694.txt:   hence will not be subject to consideration by DNS-ALG.
rfc2694.txt:   of scope for DNS-ALG (as described in section 7).
rfc2694.txt:   the DNS-ALG to be 0.
rfc2694.txt:    Figure 3: DNS-ALG operation in Bi-Directional NAT setup
rfc2694.txt:    Figure 4: DNS-ALG operation in Twice-NAT setup
rfc2694.txt:7. DNS-ALG limitations and Future Work
rfc2694.txt:   DNS-ALG. At best, DNS-ALG would be able to transform secure
dnsse
c
rfc2694.txt:   ALG, NAT and IPsec gateway (providing secure tunneling
service) a
re
rfc2694.txt:   resident on the same device, DNS-ALG will have access to the
IPse
c
rfc2694.txt:   security association keys.  The preceding section, "DNS-ALG
rfc2694.txt:   Further, with DNS-ALG, there is a possibility of denial of
servic
e
rfc2700.txt:PEM-ALG    Privacy Enhancement for Internet Electronic Mail
1
423
rfc2709.txt:   application level gateway (ALG) to make the payload
meaningful in

rfc2709.txt:   both realms. However, applications that require assistance of
an
ALG
rfc2709.txt:   they require assistance of an ALG or not, can benefit from
IPsec
rfc2709.txt:   policies administered based on private realm addressing. An
ALG w
ill
rfc2709.txt:   subject to any NAT processing. IKE-ALG simply translates
select
rfc2709.txt:   match. The following diagram illustrates how an IKE-ALG
process
rfc2709.txt:   IKE-ALG may need to request NAT to set up address bindings
and/or

rfc2709.txt:   sessions are negotiated. In the case the ALG is unable to
setup t
he
rfc2709.txt:   necessary address bindings or transport bindings, IKE-ALG
will no
t be
rfc2709.txt:   | (IPsec  | IPC-NAT MAPs             | IKE-ALG |
rfc2709.txt:   Figure 5. IKE-ALG translates Security policies, using NAT
Maps.
rfc2765.txt:      boundary of the cloud, or to use Application Layer
Gateways (A
LG)
rfc2765.txt:      on dual nodes at the cloud's boundary.  The ALG solution
is le
ss
rfc2765.txt:      also less robust since an ALG box is likely to be a single
poi
nt
rfc2766.txt:      2.4 Application Level Gateway
(ALG)...........................
  5
rfc2766.txt:   4. Use of DNS-ALG for Address
assignment.........................
  8
rfc2766.txt:   6. FTP Application Level Gateway (FTP-ALG)
Support...............
 14
rfc2766.txt:   hosts by using DNS for address resolution. A DNS-ALG
[DNS-ALG] mu
st
rfc2766.txt:   name to address mapping.  Specifically, the DNS-ALG must be
capab
le
rfc2766.txt:2.4 Application Level Gateway (ALG)
rfc2766.txt:   Application Level Gateway (ALG) [NAT-TERM] is an application
spec
ific
rfc2766.txt:   is application unaware and does not snoop the payload. ALG
could
work
rfc2766.txt:4. Use of DNS-ALG for Address Assignment
rfc2766.txt:   In any case, the DNS-ALG's principle of operation described
in th
is
rfc2766.txt:   more than one query - reply pairs. The DNS-ALG SHOULD, in
that ca
se,
rfc2766.txt:   traverse through the NAT-PT router. The DNS-ALG on the NAT-PT
dev
ice
rfc2766.txt:   server on the V6 network to the V4 node, the DNS-ALG once
again
rfc2766.txt:   DNS-ALG intercepts and translates the "A" query to "AAAA" or
"A6"

rfc2766.txt:   translated by the DNS-ALG to:
rfc2766.txt:   The DNS-ALG also holds the mapping between
FEDC:BA98::7654:3210 a
nd
rfc2766.txt:   queries for nodes residing in the V6 network causing the
DNS-ALG
to
rfc2766.txt:   for DNS-ALG intervention. Otherwise, the queries will cross
the V
6
rfc2766.txt:   domain and are subject to DNS-ALG intervention.  We recommend
rfc2766.txt:   Since Node-C may have IPv6 and/or IPv4 addresses, the DNS-ALG
on
the
rfc2766.txt:   NAT-PT. The DNS-ALG then, translates the reply adding the
appropr
iate
rfc2766.txt:   section on FTP-ALG describes the changes FTP-ALG would make
to FT
P
rfc2766.txt:6. FTP Application Level Gateway (FTP-ALG) Support
rfc2766.txt:   address and TCP port information for the data session, an
FTP-ALG
 is
rfc2766.txt:   node. FTP-ALG, facilitating transparent FTP between V4 and V6
nod
es,
rfc2766.txt:   session and uses PORT or PASV command, the FTP-ALG will
translate

rfc2766.txt:   commands, the FTP-ALG will simply translate the parameters to
the
se
rfc2766.txt:   If a V6 host originates the FTP session, however, the FTP-ALG
has
 two
rfc2766.txt:   approaches to pursue. In the first approach, the FTP-ALG will
lea
ve
rfc2766.txt:   In the second approach, the FTP-ALG will translate the
command
rfc2766.txt:   forwarding to the target V6 nodes.  However, the FTP-ALG
would be

rfc2766.txt:   reflect the new payload size. A table is used by the FTP-ALG
to
rfc2766.txt:   Application Layer Gateways (ALG) need to be incorporated to
provi
de
rfc2766.txt:   NAT-PT, in its simplest form, without the support of DNS-ALG,
rfc2766.txt:   NAT-PT  combined  with a DNS-ALG provides bi-directional
connecti
vity
rfc2766.txt:   Section 7.5 of this document states that the DNS-ALG can not
be
rfc2766.txt:   [DNS-ALG]  Srisuresh, P., Tsirtsis, G., Akkiraju, P. and A.
rfc2767.txt:   NOTE: This action is similar to that of the DNS ALG
(Application
rfc2775.txt:   gateways (ALGs) or proxies. Furthermore, the ALG or proxy
must be

rfc2800.txt:PEM-ALG    Privacy Enhancement for Internet Electronic Mail:
1
423
rfc2845.txt:         Algorithm Name   SAMPLE-ALG.EXAMPLE.
rfc2845.txt:   initial value should be "HMAC-MD5.SIG-ALG.REG.INT".
Algorithm na
mes
rfc2845.txt:   defined in RFC 2434. The algorithm name
HMAC-MD5.SIG-ALG.REG.INT
rfc2847.txt:   2.3.2.  RECOMMENDED Integrity Algorithms (I-ALG) . . . . . .
. .
. 7
rfc2847.txt:   md5WithRSAEncryption, the REQUIRED Key Establishment (K-ALG),
rfc2847.txt:   Integrity (I-ALG) and One-Way Functions for Subkey Derivation
(O-
ALG)
rfc2847.txt:   *    Integrity algorithms (I-ALG)
rfc2847.txt:           ALG that returns a zero length bit string regardless
of t
he
rfc2847.txt:           The HMAC-SHA1 algorithm is not a mandatory SPKM-3
I-ALG M
AC
rfc2847.txt:   *    Confidentiality algorithm (C-ALG).
rfc2847.txt:        ALG because it is much slower than cast5CBC. One set of
rfc2847.txt:   *    Key Establishment Algorithm (K-ALG)
rfc2847.txt:   *    One-Way Function for Subkey Derivation Algorithm (O-ALG)
rfc2847.txt:        sha1 is a MANDATORY O-ALG in SPKM-3:
rfc2847.txt:2.3.2.  RECOMMENDED Integrity Algorithms (I-ALG)
rfc2847.txt:   the lack of a target certificate, it MUST use the NULL-MAC
I-ALG
rfc2847.txt:   Because RFC 2025 requires that the RSAEncryption K-ALG be
present
,
rfc2847.txt:   the RSAEncryption K-ALG algorithm. It is also free to use an
algI
D
rfc2847.txt:   to 1 if the only K-ALG in the key-estb-set field of
Req-contents
is
rfc2847.txt:   The SPKM-3 target MUST NOT use a NULL-MAC I-ALG; it MUST use
a
rfc2847.txt:   will use the first C-ALG (privacy), and I-ALG (integrity)
algorit
hms
rfc2847.txt:   choice of cast5CBC as the MANDATORY C-ALG for SPKM-3 is
advisable
.
rfc2900.txt:PEM-ALG    Privacy Enhancement for Internet Electronic Mail:
1
423
rfc2956.txt:   NAT even with an ALG.
rfc2956.txt:   limited deployability, and/or require ALG support in NATs.
rfc2962.txt:   This document describes an SNMP application layer gateway
(ALG),
rfc2962.txt:   SNMP ALG.  Specifically, when using SNMPv3's authentication
and
rfc2962.txt:   ALG.
rfc2962.txt:   This document describes the ALG (Application Level Gateway)
for t
he
rfc2962.txt:   mapped from one group to another.  The SNMP ALG is a specific
cas
e of
rfc2962.txt:   An SNMP ALG allows network management stations to manage
multiple

rfc2962.txt:   or SNMP ALG, is a technique in which the payload of SNMP
packets
rfc2962.txt:   needed.  In this context, an SNMP ALG can be an additional
compon
ent
rfc2962.txt:   assumed to have a fixed IP address.  Thus, SNMP ALG should
only b
e
rfc2962.txt:   A typical scenario where SNMP ALG is deployed as part of NAT
is
rfc2962.txt:   |Regional Router|-----------------|Stub Router w/NAT and SNMP
ALG
|
rfc2962.txt:               Figure 1: SNMP ALG in a NAT configuration
rfc2962.txt:                         | SNMP ALG      |-----|Management
device|
rfc2962.txt:     Figure 2: Using external SNMP ALG to manage two private
network
s
rfc2962.txt:   An SNMP ALG is required to scan all the payload of SNMP
packets,
to
rfc2962.txt:   In many cases the router may be unable to handle SNMP ALG and
ret
ain
rfc2962.txt:   SNMP ALG outside the router, as described in Figure 2.
rfc2962.txt:   A basic SNMP ALG is an SNMP ALG implementation in which only
IP
rfc2962.txt:   SNMP ALG therefore does not need to be MIB aware.
rfc2962.txt:   An advanced SNMP ALG is an SNMP ALG implementation which is
capab
le
rfc2962.txt:   types. This implies that an advanced SNMP ALG is MIB aware.
rfc2962.txt:   network (i.e. the addressing realm).  The SNMP ALG described
in t
his
rfc2962.txt:   sufficient information that an advanced SNMP ALG which
understand
s
rfc2962.txt:   A NAT unfriendly textual convention requires that an SNMP
ALG, wh
ich
rfc2962.txt:   An SNMP ALG should provide transparent IP address translation
to
rfc2962.txt:   management applications.  An SNMP ALG must be compatible with
the

rfc2962.txt:   provided by the SNMP protocol.  A fully transparent SNMP ALG
must
 be
rfc2962.txt:   The SNMP ALG requires bi-directional NAT devices enroute,
that
rfc2962.txt:   a single SNMP ALG, the external addresses assumed by each of
the
NAT
rfc2962.txt:   A general SNMP ALG must be capable to translate IP addresses
in
rfc2962.txt:   SNMP ALG must reassemble IP packets which contain SNMP
messages.
 The
rfc2962.txt:   A basic SNMP ALG is an SNMP ALG implementation in which only
IP
rfc2962.txt:   basic SNMP ALG implementation parses an ASN.1/BER encoded
SNMP pa
cket
rfc2962.txt:   Once an IpAddress has been detected, the SNMP ALG checks the
rfc2962.txt:   The basic SNMP ALG does not require knowledge of any MIBs
since i
t
rfc2962.txt:   easy to implement.  A basic SNMP ALG does not change the
overall
rfc2962.txt:   However, a basic SNMP ALG is only able to translate IPv4
addresse
s in
rfc2962.txt:   ALG is not capable to translate IP addresses in objects that
are
rfc2962.txt:   basic SNMP ALG is restricted to the first out of the four
possibl
e
rfc2962.txt:   An advanced SNMP ALG is an SNMP ALG implementation which is
capab
le
rfc2962.txt:   types.  Hence, an advanced SNMP ALG may be able to
transparently
map
rfc2962.txt:   This implies that an advanced SNMP ALG must be MIB aware.
rfc2962.txt:   An advanced SNMP ALG must maintain an OBJECT IDENTIFIER (OID)
rfc2962.txt:   conceptual table is a required feature of an advanced SNMP
ALG.
IP
rfc2962.txt:   example shows that an advanced SNMP ALG may change the
overall pa
cket
rfc2962.txt:   Another effect of an advanced SNMP ALG is that it changes the
rfc2962.txt:   incorrectly report agents behind an advanced SNMP ALG as
broken S
NMP
rfc2962.txt:   size of the SNMP packet.  A basic SNMP ALG does therefore
never
rfc2962.txt:   An advanced SNMP ALG may change the size of an SNMP packet
since
a
rfc2962.txt:   receiver can handle.  An SNMP ALG which increases the size of
an
SNMP
rfc2962.txt:   anymore.  Thus, an advanced SNMP ALG may cause some SNMPv3
rfc2962.txt:   applications is not an achievable task.  The basic SNMP ALG
descr
ibed
rfc2962.txt:   base type.  Such an SNMP ALG achieves only very limited
transpare
ncy
rfc2962.txt:   SNMP ALG in place.
rfc2962.txt:   An advanced SNMP ALG described in Section 4.2 achieves better
rfc2962.txt:   transparency.  However, an advanced SNMP ALG can only claim
to be

rfc2962.txt:   understood by the advanced SNMP ALG implementation and for a
give
n
rfc2962.txt:   against unauthorized access.  Thus, an SNMP ALG must have
access
to
rfc2962.txt:   invalidating them.  Furthermore, the SNMP ALG must track any
key
rfc2962.txt:   Finally, an SNMP ALG only deals with SNMP traffic and does
not mo
dify
rfc2962.txt:   is occurring, even in the presence of an SNMP ALG.
rfc2962.txt:   (Just replace the box SNMP ALG with a box labeled SNMP PROXY
in
rfc2962.txt:   Furthermore, an SNMP ALG does not need to have knowledge of
the
rfc2962.txt:   However, the usage of SNMP ALG introduces new problems when
SNMPv
3
rfc2962.txt:   and auth/priv) can only be processed by an SNMP ALG which
support
s
rfc2962.txt:   the keys in use.  Furthermore, as keys may be updated, the
SNMP A
LG
rfc2962.txt:   SNMP ALG which maintains the keys for a set of SNMP engines
is a
rfc2962.txt:   An SNMP ALG implementation which maintains lists of
(localized) k
eys
rfc2962.txt:   use these keys.  An SNMP ALG implementation which maintains
passw
ords
rfc2962.txt:   SNMP ALG implementation must be properly secured so that
people w
ho
rfc2962.txt:       limited transparency provided by a basic SNMP ALG.  Basic
SNM
P
rfc2962.txt:       advanced SNMP ALG is much more complex and less
efficiency th
an a
rfc2962.txt:       basic SNMP ALG. An advanced SNMP ALG may break the
lexicograp
hic
rfc2962.txt:   A basic SNMP ALG as described in Section 4.1 was implemented
for
rfc2962.txt:   described in Figure 2, where SNMP ALG was combined with the
NAT
rfc2962.txt:   an internal contradiction caused by a basic SNMP ALG since
the
rfc2993.txt:    7.2.  ALG
complexity............................................
. 14
rfc2993.txt:   configured application specific gateways (ALG's), endpoints
can w
ork
rfc2993.txt:   ALG - Application Layer Gateway: inserted between application
pee
rs
rfc2993.txt:   NAT/ALG - combines ALG functions with simple NAT.  Generally
more

rfc2993.txt:   DNS/ALG -  a special case of the NAT/ALG, where an ALG for
the DN
S
rfc2993.txt:   Firewall - access control point that may be a special case of
an
ALG,
rfc2993.txt:   arbitrarily inserted.  Unlike an ALG, the application on at
least
 one
rfc2993.txt:     pair of hosts communicating through either an ALG or a NAT.
rfc2993.txt:   machines, the processing and I/O capabilities of the NAT/ALG
devi
ce
rfc2993.txt:   While RSIP addresses the transparency and ALG issues, for the
rfc2993.txt:   OSPF ALG it would actually be possible to route across a NAT
rfc2993.txt: 7.2.  ALG complexity
rfc2993.txt:   NAT/ALG was to be one or more devices at each physical
location,
and
rfc2993.txt:   the data stream carries an IP address; the central collector
or A
LG
rfc2993.txt:   As noted in the RFC-2694 [15], the DNS/ALG cannot support
secure
DNS
rfc2993.txt:   It is also the case that DNS/ALG will break any modified,
signed
rfc2993.txt:   modified by the DNS/ALG if it had access to the source
authentica
tion
rfc2993.txt:   this key, to maintain source authenticity.  So NATs that use
DNS/
ALG
rfc2993.txt:     Embedding the DNS server, or a DNS ALG in the NAT device
will
rfc2993.txt:     appropriate ALG or establish a VPN to isolate the
application f
rom
rfc2993.txt:   - If the environment uses secure DNS records, the DNS/ALG
will
rfc2993.txt:   justifications to registries        or DNS/ALG
rfc2993.txt:                                       DNS/ALG breaks DNSsec
replies

rfc2993.txt:   these technologies, NAT and the DNS/ALG work-around, hinder
rfc2993.txt:   effects from all applications. While this solves the ALG
issues,
it
rfc2999.txt:This document describes the ALG (Application Level Gateway) for
the
SNMP
rfc3000.txt:PEM-ALG    Privacy Enhancement for Internet Electronic Mail:
1
423
rfc3022.txt:   and alterations.  FTP is the most popular ALG resident on NAT
rfc3022.txt:   devices.  Applications requiring ALG intervention must not
have t
heir
rfc3022.txt:   payload encoded, as doing that would effectively disables the
ALG
,
rfc3022.txt:   unless the ALG has the key to decrypt the payload.
rfc3022.txt:   "TU Ports", "ALG" and others, used throughout the document,
may b
e
rfc3022.txt:   ALG to monitor the control session payload to determine the
ensui
ng
rfc3022.txt:   data session parameters.  FTP ALG is an integral part of most
NAT

rfc3022.txt:   The FTP ALG would require a special table to correct the TCP
sequ
ence
rfc3022.txt:   outbound from a private domain, DNS ALG may be obviated from
use
in
rfc3027.txt:   4.0 Protocols that can work with the aid of an ALG
............
8
rfc3027.txt:   transparency.  Unlike NAT, the function of ALG is application
rfc3027.txt:   ALG may be able to provide work around in some cases.  But,
if th
e
rfc3027.txt:   with a DNS-ALG might be able to offer the necessary
application l
evel
rfc3027.txt:   payload is not encrypted, an ALG may in some cases be able to
pro
vide
rfc3027.txt:   across realms.  The complexity of ALG depends on the
application
rfc3027.txt:   NAT device supports DNS-ALG.  Examples of Peer-to-peer
applicatio
ns
rfc3027.txt:   Alternately, an ALG may be required to interact with NAT to
keep
the
rfc3027.txt:   Kerberos 4 tickets are encrypted.  Therefore, an ALG cannot
be
rfc3027.txt:   not to let NAT drop the address binding.  Alternately, an ALG
wil
l
rfc3027.txt:   Therefore, an ALG cannot be written.
rfc3027.txt:      because they can easily be spoofed.  NAT and DNS-ALG
cannot wo
rk
rfc3027.txt:   NAT device might solicit the help of an ALG to replace the IP
add
ress
rfc3027.txt:   without requiring an ALG.  But, this approach increases the
secur
ity
rfc3027.txt:   available.  As the ALG tampers with the IP addresses it will
also
 not
rfc3027.txt:4.0 Protocols that can work with the aid of an ALG
rfc3027.txt:   Say, an FTP client is in a NAT supported private network.  An
FTP
 ALG
rfc3027.txt:   impossible for an ALG to update the IP addresses in the
command
rfc3027.txt:   FTP protocol, eliminating further processing through ALG, if
the
rfc3027.txt:   an RSVP-ALG must be able to replace the IP addresses based
upon t
he
rfc3027.txt:   an RSVP-ALG will not work when RSVP Integrity Object is used.
rfc3027.txt:   resolutions.  A DNS-ALG would be required to perform address
to n
ame
rfc3027.txt:   conversions on DNS queries and responses.  [DNS-ALG]
describes DN
S-
rfc3027.txt:   ALG
rfc3027.txt:   application specific session.  As a result, DNS-ALG will be
requi
red
rfc3027.txt:   server for external name lookup.  No ALG is required when the
nam
e
rfc3027.txt:   cryptographic keys, an SMTP-ALG may be used to translate the
IP
rfc3027.txt:   NAT alone, without the ALG.  This can cause problems when
debuggi
ng
rfc3027.txt:   would require a SIP-ALG.
rfc3027.txt:   significance when traversing a NAT.  Thus a SIP-ALG would
need th
e
rfc3027.txt:   As an alternative to an SIP-ALG, SIP supports a proxy server
whic
h
rfc3027.txt:   device.  A work around for this would be for the ALG to
examine t
he
rfc3027.txt:   control session.  Alternately, the ALG could simply redirect
all
rfc3027.txt:   For bi-Directional NAT, you will not need an ALG.
Bi-directional
 NAT
rfc3027.txt:   (This makes it particularly difficult for the ALG, which will
be
rfc3027.txt:   encrypted, it is impossible for the ALG to decipher the data
stre
am,
rfc3027.txt:   through a NAT device, an H.323-ALG will be required to
examine th
e
rfc3027.txt:   ALG would have to be cognizant of the various gateway
discovery
rfc3027.txt:   cases, as described in [SNMP-ALG], an SNMP ALG may be used to
rfc3027.txt:   addresses.  Such an ALG assumes static address mapping and
bi-
rfc3027.txt:   conventions) understood by the SNMP-ALG implementation and
for a
rfc3027.txt:   optionally privacy) is enabled, unless the ALG has access to
secu
rity
rfc3027.txt:   require an ALG for the games to work transparently through
rfc3027.txt:   [SNMP-ALG]   Raz, D., Schoenwaelder, J. and B. Sugla, "An
SNMP
rfc3027.txt:   [DNS-ALG]    Srisuresh, P., Tsirtsis, G., Akkiraju, P. and A.
rfc3102.txt:   requires the presence of an application layer gateway (ALG)
withi
n
rfc3102.txt:   with an ALG for FTP, which transmits IP addresses and port
number
s on
rfc3102.txt:   if an RSIP ALG is installed.  The RSIP data flow, however,
will h
ave
rfc3103.txt:   will require an application layer gateway (ALG) for any
protocol
that
rfc3234.txt:   accompanied by an ALG (Application Level Gateway - see
below).  I
t
rfc3234.txt:   In practice, SIIT and NAT-PT will both need an associated ALG
and

rfc3234.txt:   ALG; another (less common) name for them is a TLG.  As with
ALGs,

rfc3234.txt:   may be distinct, this is in practice very similar to a NAT
plus A
LG.
rfc3235.txt:   an Application Level Gateway (ALG) may still permit operation
of
the
rfc3235.txt:   protocol.  Depending on the encoding used in a protocol, an
ALG m
ay
rfc3235.txt:   that the ALG design may be simple and automated.  ALGs
typically
rfc3235.txt:   the ALG should be simple and not require excessive
computation or

rfc3235.txt:   NAT (and thus can require ALG support) are also issues for
firewa
lls.
rfc3235.txt:   new application or service, the requirement for an ALG will
limit

rfc3235.txt:   same host IP address may not function without an ALG.
rfc3235.txt:   any other simple TCP connection, and so an ALG is not
required.
rfc3235.txt:   private realm.  Through use of a DNS-ALG [RFC2694], lookups
are
rfc3235.txt:   devices, Bi-directional NAT devices (in conjunction with
DNS-ALG)
 are
rfc3257.txt:   Application Layer Gateway (ALG) which will intelligently
translat
e
rfc3278.txt:   ALG].
rfc3278.txt:   [PKI-ALG]    Bassham, L., Housley R. and W. Polk, "Algorithms
and

rfc3300.txt:PEM-ALG    Privacy Enhancement for Internet Electronic Mail:
1
423
rfc3303.txt:2.6. ALG
rfc3303.txt:   middlebox function.  An ALG examines application traffic in
trans
it
rfc3303.txt:   An ALG may be a co-resident with a middlebox or reside
externally
,
rfc3303.txt:   MIDCOM agents are entities performing ALG functions,
logically
rfc3303.txt:   ALG.
rfc3303.txt:   session tuples for which the agent is authorized to act as
ALG),
rfc3303.txt:   session tuples for which the agent is authorized to act as
ALG),
rfc3338.txt:   there isn't a DNS ALG as in NAT-PT, so there is no
interference w
ith
rfc3424.txt:   be dropped by the NAT anyway, because there's no ALG.)
rfc3489.txt:   an ALG, or MIDCOM.
rfc3600.txt:PEM-ALG    Privacy Enhancement for Internet Electronic Mail:
1
423
rfc3654.txt:   MAY support other high touch functions (e.g., NAT, ALG).
rfc3665.txt:       3.5.  Session Through a SIP ALG. . . . . . . . . . . . .
. .
. 46
rfc3665.txt:   ALG                          alg1.atlanta.example.com
192.0.2.
128
rfc3665.txt:3.5.  Session Through a SIP ALG
rfc3665.txt:   Alice             ALG           Proxy 2            Bob
rfc3665.txt:   Alice completes a call to Bob through a ALG (Application
Layer
rfc3665.txt:   Gateway) and a SIP Proxy.  The routing through the ALG is
rfc3665.txt:   that the media stream setup is not end-to-end - the ALG
terminate
s
rfc3665.txt:   both media streams and bridges them.  This is done by the ALG
rfc3665.txt:   F1 INVITE Alice -> SIP ALG
rfc3665.txt:   F2 INVITE SIP ALG -> Proxy 2
rfc3665.txt:   F3 100 Trying SIP ALG -> Alice
rfc3665.txt:   /* SIP ALG prepares to proxy data from port 192.0.2.128/2000
to
rfc3665.txt:   F5 100 Trying Proxy 2 -> SIP ALG
rfc3665.txt:   F7 180 Ringing Proxy 2 -> SIP ALG
rfc3665.txt:   F8 180 Ringing SIP ALG -> Alice
rfc3665.txt:   F10 200 OK Proxy 2 -> SIP ALG
rfc3665.txt:   F11 200 OK SIP ALG -> Alice
rfc3665.txt:   /* The ALG prepares to proxy packets from 192.0.2.128/
rfc3665.txt:   F12 ACK Alice -> SIP ALG
rfc3665.txt:   F13 ACK SIP ALG -> Bob
rfc3665.txt:   /* RTP streams are established between Alice and the ALG and
rfc3665.txt:   between the ALG and B*/
rfc3665.txt:   F14 BYE Alice -> SIP ALG
rfc3665.txt:   F15 BYE SIP ALG -> Bob
rfc3665.txt:   F16 200 OK Bob -> SIP ALG
rfc3665.txt:   F17 200 OK SIP ALG -> Alice
rfc3700.txt:PEM-ALG    Privacy Enhancement for Internet Electronic Mail:
1
423
rfc3890.txt:   ALG  - Application Level Gateway.
rfc3890.txt:   2. The SDP has been changed by an Application Level Gateway
(ALG)
.
rfc3923.txt:   o  The SHA-1 message digest as specified in [CMS-ALG] section
2.1
.
rfc3923.txt:      specified in [CMS-ALG] section 3.2.
rfc3923.txt:   o  The RSA (PKCS #1 v1.5) key transport, as specified in
[CMS-ALG
]
rfc3923.txt:   [CMS-ALG]     Housley, R., "Cryptographic Message Syntax
(CMS)
rfc4028.txt:   SIP Network Address Translator (NAT) Application Level
Gateway (A
LG)
rfc4028.txt:   [6].  The ALG embedded in a NAT will need to maintain state
for t
he
rfc4038.txt:   translated by NAT-PT DNS-ALG.  In some cases, one might be
tempte
d to
rfc4162.txt:   [SEED-ALG].  The SEED homepage,
rfc4162.txt:   [SEED-ALG]   Park, J., Lee, S., Kim, J., and J. Lee, "The
SEED
rfc4215.txt:   ALG         Application Level Gateway
rfc4215.txt:      1. Separate the DNS ALG from the NAPT-PT node (in the
"IPv6 to

rfc4226.txt:   IDEAL.  We denote ALG as either HOTP or HOTP-IDEAL for the
purpos
e of
rfc4226.txt:   K for ALG.  Both maintain a counter C, initially zero, and
the us
er
rfc4226.txt:   authenticates itself by sending ALG(K,C) to the server.  The
latt
er
rfc4226.txt:   ALG(K,i) for some i in the range C,...,C + s-1, where s is
the
rfc4226.txt:   algorithm ALG is being used, knowing the system design, and
knowi
ng
rfc4226.txt:   ALG: K x {0,1}^c --> R.
rfc4226.txt:      A = ALG(K,C)
rfc4226.txt:         If A == ALG(K,i) then Win = TRUE; C = i + 1
rfc4472.txt:      8.1. NAT-PT with DNS-ALG
.....................................
..18
rfc4472.txt:8.1.  NAT-PT with DNS-ALG
rfc4472.txt:   The DNS-ALG component of NAT-PT [RFC2766] mangles A records
to lo
ok
rfc4635.txt:   HMAC-MD5.SIG-ALG.REG.INT name for authentication codes using
the
HMAC
rfc4635.txt:   ALG.REG.INT, based on MD5 [RFC1321].
rfc4635.txt:   The current HMAC-MD5.SIG-ALG.REG.INT and gss-tsig identifiers
are

rfc4635.txt:      Mandatory      HMAC-MD5.SIG-ALG.REG.INT
rfc4787.txt:         the NAT administrator to enable or disable each ALG
separat
ely.
rfc4787.txt:      standards track specifications that define an ALG can
update t
his
rfc4787.txt:         the NAT administrator to enable or disable each ALG
separat
ely.
rfc4852.txt:   Application Layer Gateway (ALG) between the incompatible
hosts.
rfc4852.txt:   diverse transition mechanisms.  For example, an ALG
collocated wi
th
rfc4924.txt:      proxies.  Furthermore, the ALG or proxy must be updated
whenev
er a
rfc4924.txt:   implementations.  No matter how well an ALG is implemented,
barri
ers
rfc4924.txt:   "transparent ALG" is a contradiction in terms.
rfc4961.txt:   Gateway (ALG) functionality.  Such NATs require that
endpoints us
e
rfc4966.txt:   2.  Issues Unrelated to an DNS-ALG . . . . . . . . . . . . .
. .
.  7
rfc4966.txt:   3.  Issues Exacerbated by the Use of DNS-ALG . . . . . . . .
. .
. 13
rfc4966.txt:   4.  Issues Directly Related to Use of DNS-ALG  . . . . . . .
. .
. 16
rfc4966.txt:     4.4.  DNS-ALG and Multi-Addressed Nodes  . . . . . . . . .
. .
. 19
rfc4966.txt:   o  Issues with NAT-PT DNS ALG (Application Layer Gateway) in
RFC
2766
rfc4966.txt:      [DNS-ALG-ISSUES]
rfc4966.txt:   o  NAT-PT DNS ALG Solutions [DNS-ALG-SOL]
rfc4966.txt:   Layer Gateway (ALG) for DNS (referred to as DNS-ALG in this
docum
ent)
rfc4966.txt:   NAT-PT could avoid the use of the DNS-ALG.
rfc4966.txt:   passed to the hosts in the absence of the DNS-ALG.
Therefore, th
is
rfc4966.txt:   document assumes that the DNS-ALG is an integral part of
NAT-PT;
rfc4966.txt:   accordingly, issues with the DNS-ALG must be considered as
issues
 for
rfc4966.txt:   Note that issues not specifically related to the use of the
DNS-A
LG
rfc4966.txt:   o  Issues that are independent of the use of a DNS-ALG and
are,
rfc4966.txt:   o  Issues that are exacerbated by the use of a DNS-ALG and
are,
rfc4966.txt:         ALG to create address mappings with limited lifetimes
means

rfc4966.txt:   o  Issues that result from the use of a DNS-ALG and are,
therefor
e,
rfc4966.txt:      *  Address selection issues and resource consumption in a
DNS-
ALG
rfc4966.txt:      *  Limitations on DNS security capabilities when using a
DNS-A
LG.
rfc4966.txt:2.  Issues Unrelated to an DNS-ALG
rfc4966.txt:   the consequences as part of the description of the FTP ALG.
Simi
lar
rfc4966.txt:   Assuming that the NAT-PT contains a colocated ALG for one of
the
rfc4966.txt:   relevant protocols, the ALG could replace the embedded IP
address
es
rfc4966.txt:   SCTP will need an associated "ALG" -- actually a Transport
Layer
rfc4966.txt:   naively implemented DNS-ALG could create such bindings from
spoof
ed
rfc4966.txt:3.  Issues Exacerbated by the Use of DNS-ALG
rfc4966.txt:   DNS-ALG in the NAT-PT to provide the mapped address needed to
rfc4966.txt:   IPv6 router for the site so that the DNS-ALG is able to
examine a
ll
rfc4966.txt:   These constraints are described in more detail in
[DNS-ALG-ISSUES
].
rfc4966.txt:   [DNS-ALG-SOL] proposes a solution for flows initiated from
the IP
v6
rfc4966.txt:   addresses would also use the NAT-PT DNS-ALG.
rfc4966.txt:   point of failure in the network.  The addition of the DNS-ALG
in
rfc4966.txt:   Using the DNS-ALG to create address bindings requires that
the
rfc4966.txt:   Additionally, the DNS-ALG needs to determine the initial
lifetime
 of
rfc4966.txt:   be determined heuristically.  The DNS-ALG does not know which
rfc4966.txt:   an extended ALG (which has all the issues discussed in
Section 2.
1)
rfc4966.txt:   The use of the DNS-ALG in NAT-PT introduces another
vulnerability

rfc4966.txt:   [DNS-ALG-ISSUES] exploits the use of DNS queries traversing
NAT-P
T to
rfc4966.txt:   [DNS-ALG-SOL] proposes to mitigate the DoS attack by using
Access

rfc4966.txt:4.  Issues Directly Related to Use of DNS-ALG
rfc4966.txt:   [DNS-ALG-ISSUES] discusses NAT-PT DNS-ALG issues with regard
to
rfc4966.txt:   address selection.  As specified in [RFC2766], the DNS-ALG
return
s
rfc4966.txt:   [DNS-ALG-SOL] proposes a solution that involves modification
to t
he
rfc4966.txt:   o  When a DNS AAAA query traverses the NAT-PT DNS-ALG, the
NAT-PT

rfc4966.txt:         it returns them.  The DNS-ALG then forwards this
response t
o
rfc4966.txt:         The NAT-PT DNS-ALG will intercept the error or empty
return
 and
rfc4966.txt:         IPv4 address, the ALG creates a binding and synthesizes
a
rfc4966.txt:      passing through a DNS ALG because the NAT-PT may have to
make
two
rfc4966.txt:   selection that is identified in [DNS-ALG-ISSUES].
Applications h
ave
rfc4966.txt:   no way of knowing that the IPv6 address returned from the
DNS-ALG
 is
rfc4966.txt:   through the NAT-PT DNS-ALG, the DNS-ALG will translate the
respon
se
rfc4966.txt:   happens because the DNS-ALG specified in [RFC2766] operates
rfc4966.txt:   state about queries passed through the DNS-ALG, and hence to
resp
ond
rfc4966.txt:4.4.  DNS-ALG and Multi-Addressed Nodes
rfc4966.txt:   these addresses.  Since the DNS-ALG in the NAT-PT has no
knowledg
e
rfc4966.txt:   to authenticate DNS responses.  The DNS-ALG modifies DNS
query
rfc4966.txt:   Workarounds have been proposed, such as making the DNS-ALG
behave

rfc4966.txt:   [DNS-ALG-ISSUES]  Durand, A., "Issues with NAT-PT DNS ALG in
rfc4966.txt:   [DNS-ALG-SOL]     Hallingby, P. and S. Satapati, "NAT-PT DNS
ALG
rfc4973.txt:       BIT CSPF - A CSPF algorithm support TLV
TE-NODE-TLV-CSPF-ALG
rfc4973.txt:   TE-NODE-TLV-CSPF-ALG             Section 8.1.2.3  0x8003
rfc5055.txt:   The algorithm identifier for SHA-1 is imported from
[PKIX-ALG].
It
rfc5055.txt:   defined in [PKIX-ALG] and [PKIX-ALG2], but other signature
algori
thms
rfc5055.txt:   certificate [PKIX-1].  Supported algorithms are defined in
[PKIX-
ALG]
rfc5055.txt:   specified in [PKIX-ALG].  SCVP servers that support
serverPublicK
eys
rfc5055.txt:   [PKIX-ALG]    Bassham, L., Polk, W., and R. Housley,
"Algorithms
and
rfc5245.txt:   If an ALG is SIP aware but not ICE aware, ICE will work
through i
t as
rfc5245.txt:   long as the ALG correctly modifies the SDP.  A correct ALG
rfc5245.txt:   o  The ALG does not modify the m and c lines or the rtcp
attribut
e if
rfc5245.txt:      depends on the state of the ALG:
rfc5245.txt:         If the ALG already has a binding established that maps
an
rfc5245.txt:         values in the m and c lines or rtcp attribute, the ALG
uses

rfc5245.txt:         If the ALG does not already have a binding, it creates
a ne
w
rfc5245.txt:   prevents the ALG from manipulating the SDP messages and
interferi
ng
rfc5245.txt:   to provide "generic" ALG functionality.  These generic ALGs
hunt
for
rfc5274.txt:   SignedData (see [CMS-ALG]).  Entities MAY verify other
signature
rfc5274.txt:   SignedData (see [CMS-ALG]).  Other signatures algorithms MAY
be u
sed
rfc5274.txt:   EnvelopedData (see [CMS-ALG]).  All entities SHOULD support
RSA-O
AEP
rfc5274.txt:   [CMS-ALG]          Housley, R., "Cryptographic Message Syntax
(CM
S)
rfc5382.txt:   Gateway (ALG) behavior that may interfere with NAT traversal.
rfc5382.txt:      ALG is left unspecified because of legacy concerns: as of
writ
ing
rfc5382.txt:      passive (PASV) mode by default and require an ALG to
traverse
rfc5382.txt:   privacy reasons or for ALG support) must ensure that TCP
packets
with
rfc5389.txt:   but misguided attempt at providing a generic ALG function.
Such
rfc5480.txt:   (ECC).  It updates RFC 3279 [PKI-ALG].  This document
specifies t
he
rfc5480.txt:   [PKI-ALG] and [PKI-ADALG], even though the associated text is
rfc5480.txt:   unaffected.  By updating all of the ASN.1 from [PKI-ALG] in
this
rfc5480.txt:     -- Note that in [PKI-ALG] the secp192r1 curve was referred
to a
s
rfc5480.txt:   The security considerations in [PKI-ALG] apply.
rfc5480.txt:   As noted in [PKI-ALG], the use of MD2 and MD5 for new
application
s is
rfc5480.txt:   Value [PKI-ALG].  If an implementation needs to use these
options
,
rfc5480.txt:   [PKI-ALG]    Bassham, L., Polk, W., and R. Housley,
"Algorithms a
nd
rfc5480.txt:   -- Note that in [PKI-ALG] the secp192r1 curve was referred to
as
rfc5597.txt:   needed for an Application Level Gateway (ALG) to function
properl
y.
rfc5753.txt:   static-static DH, which is specified in [CMS-ALG].
Ephemeral-sta
tic
rfc5753.txt:   specified jointly in the documents [CMS-ALG] and [CMS-DH].
rfc5753.txt:   [PKI-ALG].
rfc5753.txt:   in [CMS-ALG] and [CMS-SHA2].
rfc5753.txt:   in [PKI-ALG].
rfc5753.txt:   [CMS-ALG] and [CMS-AES].
rfc5753.txt:   algorithms are found in [CMS-ALG] and [CMS-AES].  The content
rfc5753.txt:   algorithms are found in [CMS-ALG] and [HMAC-SHA2].
rfc5753.txt:   ECDSA-Sig-Value is specified in [PKI-ALG].  Within CMS,
ECDSA-Sig
-
rfc5753.txt:   the elliptic curve domain parameters specified by [PKI-ALG].
rfc5753.txt:   [CMS-ALG], [CMS-AUTHENV], [CMS-DH], [CMS-SHA2], [FIPS180-3],
rfc5753.txt:   lists curves [PKI-ALG] for the key sizes.
rfc5753.txt:   sizes and message digest algorithms.  It also lists curves
[PKI-A
LG]
rfc5753.txt:   [CMS-ALG]      Housley, R., "Cryptographic Message Syntax
(CMS)
rfc5753.txt:   [PKI-ALG]      Turner, S., Brown, D., Yiu, K., Housley, R.,
and T
.
rfc5753.txt:   -- From [PKI-ALG]
rfc5753.txt:   -- From [CMS-ALG]
rfc5753.txt:   -- Message Digest Algorithms: Imported from [PKI-ALG] and
[RSAOAE
P]
rfc5753.txt:   -- Signature Algorithms: Imported from [PKI-ALG]
rfc5753.txt:   -- Key Wrap Algorithms: Imported from [CMS-ALG] and [CMS-AES]
rfc5753.txt:   -- Content Encryption Algorithms: Imported from [CMS-ALG]
rfc5753.txt:   -- Originator Public Key Algorithms: Imported from [PKI-ALG]
rfc5753.txt:   -- [PKI-ALG]
rfc5753.txt:   --   commented out in [PKI-ALG]  implicitCurve   NULL
rfc5753.txt:   --   commented out in [PKI-ALG]  specifiedCurve
SpecifiedECDomai
n
rfc5753.txt:   --   commented out in [PKI-ALG]  ...
rfc5753.txt:-- ECDSA Signature Value: Imported from [PKI-ALG]
rfc5753.txt:-- [PKI-ALG]
rfc5753.txt:--   commented out in [PKI-ALG] implicitCurve   NULL
rfc5753.txt:--   commented out in [PKI-ALG] specifiedCurve
SpecifiedECDomain
rfc5753.txt:--   commented out in [PKI-ALG] ...
rfc5780.txt:     3.6.  Detecting a Generic Application Level Gateway (ALG)
. .
. 11
rfc5780.txt:3.6.  Detecting a Generic Application Level Gateway (ALG)
rfc5780.txt:   to provide "generic" ALG functionality.  These generic ALGs
hunt
for
rfc5780.txt:   not match, there is a NAT with a generic ALG in the path.
This t
est
rfc5857.txt:      [CRYPTO-ALG] (or its successor).
rfc5857.txt:   [CRYPTO-ALG] Manral, V., "Cryptographic Algorithm
Implementation
rfc5858.txt:      [CRYPTO-ALG] (or its successor).
rfc5858.txt:   [CRYPTO-ALG]  Manral, V., "Cryptographic Algorithm
Implementation

rfc5912.txt:   -- Note that in [PKI-ALG] the secp192r1 curve was referred to
as
rfc6071.txt:   IKE-ALG (Application Level Gateway) that translates policies
from

rfc759.txt:  14     ENCRYPT   CODE(1),COUNT(3),ALG-ID(1),
rfcxx00.txt:PEM-ALG    Privacy Enhancement for Internet Electronic Mail:
1
423