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<?xml version="1.0" encoding="iso-2022-jp"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
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<html xmlns:h="http://www.w3.org/1999/xhtml" xmlns="http://www.w3.org/1999/xhtml">
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<head profile="http://suika.fam.cx/~wakaba/lang/rfc/translation/html-profile">
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<meta http-equiv="Content-Style-Type" content="text/css"/>
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<title>
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RFC 1428:
|
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Internet $B%a%$%k$N(B8$B$^$s$^Aw$j$+$i(B8$B%S%C%H(B SMTP/MIME $B$X$NJQ49(B (Transition of Internet Mail from Just-Send-8 to 8bit-SMTP/MIME)
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</title>
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<link rel="stylesheet" href="http://suika.fam.cx/~wakaba/lang/rfc/translation/rfc-ja-style.css" type="text/css"/>
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<meta name="ietf-workgroup" content="SMTP Extensions Working Group"/>
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<style xml:space="preserve" type="text/css">
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.rfc-t-artwork table
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{margin-left: 15%; margin-right: 15%;
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border-style: none}
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.rfc-t-artwork table thead th
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{border-left: thin ActiveBorder solid;
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padding: 0.2em; text-align: left}
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.rfc-t-artwork table thead th.css-first-child
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{border-left-style: none}
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.rfc-t-artwork table tbody th
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{border-top: thin ActiveBorder solid;
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padding: 0.2em; text-align: right; vertical-align: middle}
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.rfc-t-artwork table tbody td
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{border-top: thin ActiveBorder solid;
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border-left: thin ActiveBorder solid;
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padding: 0.2em; text-align: center; vertical-align: middle}
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</style>
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</head>
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<body>
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<div id="rfc--table">
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<ul id="rfc--table-left">
|
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<li>Network Working Group</li>
|
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<li>Request for Comments: 1428</li>
|
| 35 |
</ul>
|
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<ul id="rfc--table-right">
|
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<li title="Greg Vaudreuil">G. Vaudreuil</li>
|
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<li title="Corporation for National Research Initiatives">CNRI</li>
|
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<li>
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<span class="t-pair">
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<span xml:lang="en" class="t-l-en"> February 1993</span>
|
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</span>
|
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</li>
|
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<li>
|
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<span class="t-pair">
|
| 46 |
<span xml:lang="ja" class="t-l-ja">1993$BG/(B2$B7n(B</span>
|
| 47 |
</span>
|
| 48 |
</li>
|
| 49 |
</ul>
|
| 50 |
</div>
|
| 51 |
<div class="t-pair t-heading" id="rfc-title">
|
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<h1 class="rfc-title t-l-en" xml:lang="en">Transition of Internet Mail from Just-Send-8 to 8bit-SMTP/MIME</h1>
|
| 53 |
<h1 class="rfc-title t-l-ja" xml:lang="ja">Internet $B%a%$%k$N(B8$B$^$s$^Aw$j$+$i(B8$B%S%C%H(B SMTP/MIME $B$X$NJQ49(B</h1>
|
| 54 |
</div>
|
| 55 |
<div id="rfc-status" class="rfc-section">
|
| 56 |
<div class="t-pair">
|
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<h1 xml:lang="en" class="t-l-en">Status of this Memo</h1>
|
| 58 |
<h1 xml:lang="ja" class="t-l-ja">$B$3$N%a%b$N0LCVIU$1(B</h1>
|
| 59 |
</div>
|
| 60 |
<div class="rfc-t">
|
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<div class="t-pair">
|
| 62 |
<p class="t-l-en" xml:lang="en">
|
| 63 |
This memo provides information for the Internet community.
|
| 64 |
It does not specify an Internet standard of any kind.
|
| 65 |
Distribution of this memo is unlimited.
|
| 66 |
</p>
|
| 67 |
<p class="t-l-ja" xml:lang="ja">
|
| 68 |
$B$3$N%a%b$O!"(B Internet $B<R2q$K>pJs$rDs6!$7$^$9!#$$$+$J$k<oN`$N(B
|
| 69 |
Internet $BI8=`$r5,Dj$9$k$b$N$G$b$"$j$^$;$s!#$3$N%a%b$NG[I[$O@)8B$7$^$;$s!#(B
|
| 70 |
</p>
|
| 71 |
</div>
|
| 72 |
</div>
|
| 73 |
</div>
|
| 74 |
<div class="rfc-section" id="rfc.abstract">
|
| 75 |
<div class="t-pair t-heading">
|
| 76 |
<h1 xml:lang="en" class="t-l-en">Abstract</h1>
|
| 77 |
<h1 xml:lang="ja" class="t-l-ja">$B35MW(B</h1>
|
| 78 |
</div>
|
| 79 |
<div class="rfc-t">
|
| 80 |
<div class="t-pair">
|
| 81 |
<p xml:lang="en" class="t-l-en">
|
| 82 |
Protocols for extending SMTP to pass 8bit characters have been
|
| 83 |
defined <span class="rfc-xref">
|
| 84 |
<a href="#refs.RFC1425" title="SMTP Service Extensions">[3]</a>
|
| 85 |
</span> <span class="rfc-xref">
|
| 86 |
<a href="#refs.RFC1426" title="SMTP Service Extensions for 8bit MIMEtransport">[4]</a>
|
| 87 |
</span>.
|
| 88 |
These protocols require that messages transported by
|
| 89 |
the extended SMTP are to be encoded in MIME
|
| 90 |
<span class="rfc-xref">
|
| 91 |
<a href="#refs.RFC1341" title="Multipurpose Internet Mail Extensions">[1]</a>
|
| 92 |
</span> <span class="rfc-xref">
|
| 93 |
<a href="#refs.RFC1342" title="Representation of Non-ASCII Text in Internet Message Headers">[2]</a>
|
| 94 |
</span>.
|
| 95 |
Before work began on these protocols, several SMTP implementations
|
| 96 |
adopted ad-hoc mechanisms for sending 8bit data. It is desirable
|
| 97 |
for the extended SMTP environment and these ad hoc mechanisms
|
| 98 |
interoperate. This document outlines the problems in this
|
| 99 |
environment and an approach to minimizing the cost of transition
|
| 100 |
from current usage of non-MIME 8bit messages to MIME.
|
| 101 |
</p>
|
| 102 |
<p xml:lang="ja" class="t-l-ja">
|
| 103 |
8$B%S%C%HJ8;z$rDL2a$5$;$k$h$&$K(B SMTP
|
| 104 |
$B$r3HD%$9$k%W%m%H%3%k$,Dj5A$5$l$F$$$^$9(B
|
| 105 |
<a href="#refs.RFC1425" title="SMTP $B%5!<%S%93HD%(B">[3]</a> <a href="#refs.RFC1426" title="8$B%S%C%H(B MIME $BE>AwMQ(B SMTP $B%5!<%S%93HD%(B">[4]</a>$B!#(B
|
| 106 |
$B$3$l$i$N%W%m%H%3%k$G$O!"3HD%(B SMTP $B$GE>Aw$5$l$k%a%C%;!<%8$,(B
|
| 107 |
MIME <a href="#refs.RFC1341" title="$BB?L\E*(B Internet $B%a%$%k3HD%(B">[1]</a> <a href="#refs.RFC1342" title="$BHs(B ASCII $BJ8$N(B Internet $B%a%C%;!<%8F,$K$*$1$kI=8=(B">[2]</a>
|
| 108 |
$B$GId9f2=$5$l$F$$$k$3$H$,I,MW$G$9!#$3$l$i$N%W%m%H%3%k$N:n6H$,;O$^$k0JA0!"4v$D$+$N(B
|
| 109 |
SMTP $B<BAu$O(B8$B%S%C%H!&%G!<%?$rAw?.$9$k$?$a$NFC@_5!9=$r:NMQ$7$F$$$^$7$?!#3HD%(B
|
| 110 |
SMTP $B4D6-$H$3$NMM$JFC@_5!9=$,6(D4$7$FF/$/$3$H$,K>$^$7$$$G$9!#$3$NJ8=q$O!"$3$l$i$N4D6-$G$NLdBj$H!"Hs(B MIME 8$B%S%C%H!&%a%C%;!<%8$N8=:_$NMxMQK!$+$i(B
|
| 111 |
MIME $B$X$NJQ49$N7PHq$N:G>.2=$NJ}K!$K$D$$$F35@b$7$^$9!#(B
|
| 112 |
</p>
|
| 113 |
</div>
|
| 114 |
</div>
|
| 115 |
</div>
|
| 116 |
|
| 117 |
<div class="rfc-section" id="rfc.section.1">
|
| 118 |
<div class="t-pair t-heading">
|
| 119 |
<h1 xml:lang="en" class="t-l-en">1. Terminology</h1>
|
| 120 |
<h1 xml:lang="ja" class="t-l-ja">1.
|
| 121 |
$BMQ8l(B</h1>
|
| 122 |
</div>
|
| 123 |
<div class="rfc-t" id="rfc.section.1.p.1">
|
| 124 |
<div class="t-pair">
|
| 125 |
<p xml:lang="en" class="t-l-en">
|
| 126 |
RFC 821 defines a 7bit transport. A transport agent which does not
|
| 127 |
clear the high order bit upon receipt of octets with this bit set in
|
| 128 |
SMTP messages is called 8 bit transparent in this document. An
|
| 129 |
implementation of the general SMTP Extensions document
|
| 130 |
<span class="rfc-xref">
|
| 131 |
<a href="#refs.RFC1425" title="SMTP Service Extensions">[3]</a>
|
| 132 |
</span> and the
|
| 133 |
8bit extensions protocol <span class="rfc-xref">
|
| 134 |
<a href="#refs.RFC1426" title="SMTP Service Extensions for 8bit MIMEtransport">[4]</a>
|
| 135 |
</span>
|
| 136 |
which passes MIME messages using all 8
|
| 137 |
bits of an octet is called 8bit ESMTP. An implementation of extended
|
| 138 |
SMTP which does not accept 8bit characters is called 7bit ESMTP. A
|
| 139 |
gateway is defined to be a transport agent with User Agent authority
|
| 140 |
to alter or convert the content of a message.
|
| 141 |
</p>
|
| 142 |
<p xml:lang="ja" class="t-l-ja">
|
| 143 |
<a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:821" title="RFC 821">RFC 821</a> $B$O(B8$B%S%C%HE>Aw$rDj5A$7$F$$$^$9!#(B
|
| 144 |
SMTP $B%a%C%;!<%8Cf$N<u$1<h$C$?%*%/%F%C%H$N:G>e0L%S%C%H$r!"$3$N%S%C%H$KCM$r@_Dj$9$k$3$H$G>C5n$7$J$$E>AwBeM}<T$r!"$3$NJ8=q$G$O(B8$B%S%C%HF)2a$H8F$S$^$9!#0lHL(B
|
| 145 |
SMTP $B3HD%J8=q(B <a href="#refs.RFC1425" title="SMTP $B%5!<%S%93HD%(B">[3]</a> $B5Z$S(B
|
| 146 |
MIME $B%a%C%;!<%8$r%*%/%F%C%H$N(B8$B%S%C%HA4$F$r;H$C$FEO$9(B8$B%S%C%H3HD%%W%m%H%3%k(B
|
| 147 |
<a href="#refs.RFC1426" title="8$B%S%C%H(B MIME $BE>AwMQ(B SMTP $B%5!<%S%93HD%(B">[4]</a> $B$N<BAu$r(B8$B%S%C%H(B
|
| 148 |
ESMTP $B$H8F$S$^$9!#(B8$B%S%C%HJ8;z$r<u$1IU$1$J$$3HD%(B SMTP
|
| 149 |
$B$N<BAu$r(B7$B%S%C%H(B ESMTP $B$H8F$S$^$9!#4XLg(B (gateway)
|
| 150 |
$B$O!"%a%C%;!<%8$NFbMF$rJQ$($k!&JQ49$9$kMxMQ<TBeM}<TEv6I$D$-E>AwBeM}<T$HDj5A$7$^$9!#(B
|
| 151 |
</p>
|
| 152 |
</div>
|
| 153 |
</div>
|
| 154 |
</div>
|
| 155 |
|
| 156 |
<div class="rfc-section" id="rfc.section.2">
|
| 157 |
<div class="t-pair t-heading">
|
| 158 |
<h1 xml:lang="en" class="t-l-en">2. The Problem</h1>
|
| 159 |
<h1 xml:lang="ja" class="t-l-ja">2.
|
| 160 |
$BLdBjE@(B</h1>
|
| 161 |
</div>
|
| 162 |
<div class="rfc-t" id="rfc.section.2.p.1">
|
| 163 |
<div class="t-pair">
|
| 164 |
<p xml:lang="en" class="t-l-en">
|
| 165 |
SMTP as defined in RFC 821 limits the sending of Internet Mail to
|
| 166 |
US-ASCII <span class="rfc-xref">
|
| 167 |
<a href="#refs.ASCII" title="Coded Character Set$B!=!=(B7-Bit American Standard Code for Information Interchange">[5]</a>
|
| 168 |
</span> characters. As the Internet
|
| 169 |
has grown to include non-English correspondents, the need to
|
| 170 |
communicate with character sets
|
| 171 |
other than US-ASCII has prompted many vendors and users to extend
|
| 172 |
SMTP or RFC 822 to use non-ASCII character sets. Common approaches
|
| 173 |
are to send 7 bit national variant ISO 646 character sets over
|
| 174 |
current RFC822/SMTP, to extend SMTP and RFC822 to use 8bit ISO 8859
|
| 175 |
character sets, and to use proprietary PC character sets.
|
| 176 |
</p>
|
| 177 |
<p xml:lang="ja" class="t-l-ja">
|
| 178 |
<a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:821" title="RFC 821">RFC 821</a> $B$GDj5A$5$l$?(B SMTP $B$O(B
|
| 179 |
Internet $B%a%$%k$NAw?.$r(B US-ASCII <a href="#refs.ASCII" title="$BId9f2=J8;z=89g!=!=(B7$B%S%C%H$N>pJs8r49MQ0!JFMx2CI8=`Id9f(B">[5]</a>
|
| 180 |
$BJ8;z$K@)8B$7$F$$$^$7$?!#(B Internet
|
| 181 |
$B$,Hs1Q8lJ8DL<T$r4^$`MM$K@.D9$9$k$K=>$$!"Hs(B US-ASCII
|
| 182 |
$BJ8;z=89g$K$h$k0U;WABDL$NI,MW@-$+$i!"B?$/$N@=B$<T$dMxMQ<T$,(B SMTP
|
| 183 |
$B$d(B <a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:822" title="RFC 822">RFC 822</a> $B$rHs(B ASCII
|
| 184 |
$BJ8;z=89g$r;HMQ$9$k$h$&$K3HD%$7$h$&$H$7$^$7$?!#$=$N6&DL$N<jCJ$K$O(B7$B%S%C%H$N9q2HHG(B
|
| 185 |
ISO 646 $BJ8;z=89g$r8=9T$N(B RFC 822/SMTP $B$GAw?.$9$k(B, SMTP $B$H(B
|
| 186 |
RFC822 $B$r(B8$B%S%C%H$N(B ISO 8859 $BJ8;z=89g$r;HMQ$9$k$h$&$K3HD%$9$k(B,
|
| 187 |
$BFH@j(B PC $BJ8;z=89g$r;HMQ$9$k(B, $B$,$"$j$^$9!#(B
|
| 188 |
</p>
|
| 189 |
</div>
|
| 190 |
</div>
|
| 191 |
|
| 192 |
<div class="rfc-t" id="rfc.section.2.p.2">
|
| 193 |
<div class="t-pair">
|
| 194 |
<p xml:lang="en" class="t-l-en">
|
| 195 |
A third approach is used for Japanese mail. Japanese characters are
|
| 196 |
represented by pairs of octets with the high order bit cleared.
|
| 197 |
Switching between 14 bit character sets and 7 bit character sets is
|
| 198 |
indicated within the message by ISO 2022 escape sequences.
|
| 199 |
</p>
|
| 200 |
<p xml:lang="ja" class="t-l-ja">
|
| 201 |
$B;0HVL\$NJ}K!$OF|K\8l%a%$%k$K;H$o$l$F$$$^$9!#F|K\8lJ8;z$O:G>e0L%S%C%H$,>C5n$5$l$?%*%/%F%C%H$NAH9g$;$GI=8=$7$^$9!#(B14$B%S%C%HJ8;z=89g$H(B7$B%S%C%HJ8;z=89g$O%a%C%;!<%8Cf$G$O(B
|
| 202 |
ISO 2022 $B%(%9%1!<%WNs$G@Z$jBX$($^$9!#(B
|
| 203 |
</p>
|
| 204 |
</div>
|
| 205 |
</div>
|
| 206 |
<ins class="t-note t-l-ja" xml:lang="ja">
|
| 207 |
<span class="t-note-title">$BLuCm(B:</span>
|
| 208 |
<p class="rfc-t" id="rfc.section.2.p.1">$B;0HVL\$NJ}K!$H$O!VFH@j(B PC $BJ8;z=89g$N;HMQ!W$G$9$+$i!"$3$N@bL@$G$O9gCW$7$^$;$s!#$*$=$i$/!";0HVL\$NJ}K!$O!"!V0lHVL\!&FsHVL\0J30$NJ}K!!W$H$G$b$7$?$+$C$?$N$G$7$g$&!#(B</p>
|
| 209 |
</ins>
|
| 210 |
|
| 211 |
<div class="rfc-t" id="rfc.section.2.p.3">
|
| 212 |
<div class="t-pair">
|
| 213 |
<p xml:lang="en" class="t-l-en">
|
| 214 |
So long as these implementations can communicate without intermediate
|
| 215 |
transformations and have a loose private agreement on the use of a
|
| 216 |
specific character set without tagging, basic mail service can be
|
| 217 |
provided.
|
| 218 |
</p>
|
| 219 |
<p xml:lang="ja" class="t-l-ja">
|
| 220 |
$B$3$l$i$N<BAu$OESCf7PO)$G$NJQ7AL5$7$KDL?.=PMh!"FCDjJ8;z=89g$N;%L5$7$G$N;HMQ$N4K$$;dE*$J9g0U$,$"$k$N$G!"4pK\E*$J%a%$%k!&%5!<%S%9$,Ds6!=PMh$^$9!#(B
|
| 221 |
</p>
|
| 222 |
</div>
|
| 223 |
</div>
|
| 224 |
|
| 225 |
<div class="rfc-t" id="rfc.section.2.p.4">
|
| 226 |
<div class="t-pair">
|
| 227 |
<p xml:lang="en" class="t-l-en">
|
| 228 |
In the transition to the negotiated 8bit ESMTP/MIME environment, it
|
| 229 |
is important that mail sent by a currently non-conforming user can be
|
| 230 |
read by another non-conforming user. This existing functionality is
|
| 231 |
reduced by conversion from 8bit text to text encoded in unreadable
|
| 232 |
Base-64 or "garbled" text encoded in quoted printable.
|
| 233 |
</p>
|
| 234 |
<p xml:lang="ja" class="t-l-ja">
|
| 235 |
$B@^>W(B8$B%S%C%H(B ESMTP/MIME
|
| 236 |
$B4D6-$X$NJQ49$G!"8=:_HsE,9g$NMxMQ<T$,Aw?.$7$?%a%$%k$OB>$NHsE,9g$NMxMQ<T$,FI$`$3$H$,=PMh$k$3$H$O=EMW$G$9!#$3$N4{B85!G=@-$O!"(B8$B%S%C%HJ8$+$iIT2DFI(B
|
| 237 |
Base-64 $B$GId9f2=$5$l$?J8$d(B quoted printable
|
| 238 |
$B$GId9f2=$5$l$?!VJ8;z2=$1$7$?!WJ8$KJQ49$9$k$3$H$G8:>/$7$^$9!#(B
|
| 239 |
</p>
|
| 240 |
</div>
|
| 241 |
</div>
|
| 242 |
|
| 243 |
<div class="rfc-t" id="rfc.section.2.p.5">
|
| 244 |
<div class="t-pair">
|
| 245 |
<p xml:lang="en" class="t-l-en">
|
| 246 |
There are several interesting non-interoperable cases that currently
|
| 247 |
exist in non US-ASCII mail and several new ones likely to emerge in a
|
| 248 |
transition to 8bit/MIME. Below is a listing of the
|
| 249 |
transition-to-mime cases. Only solutions to <span class="rfc-xref">
|
| 250 |
<a href="#s2.i4">(4)</a>
|
| 251 |
</span>
|
| 252 |
in the context of a translating gateway are discussed in this memo.
|
| 253 |
</p>
|
| 254 |
<p xml:lang="ja" class="t-l-ja">
|
| 255 |
$B8=:_Hs(B US-ASCII $B%a%$%k$KB8:_$9$k6=L#?<$$Aj8_DL?.IT2D$J;vNc!"$"$k$$$O(B8$B%S%C%H(B/MIME
|
| 256 |
$B$X$NJQ49$GIb>e$7$=$&$J?7$7$$;vNc$,4v$D$+$"$j$^$9!#2<$K5s$2$k$N$O!"(B
|
| 257 |
MIME $B$X$NJQ49$N;vNc$G$9!#JQ494XLg$K$*$1$k(B <a href="#s2.i4">(4)</a>
|
| 258 |
$B$N2r7h:v$N$_$r$3$N%a%b$G$O<h$j>e$2$^$9!#(B
|
| 259 |
</p>
|
| 260 |
</div>
|
| 261 |
</div>
|
| 262 |
|
| 263 |
<div class="rfc-figure">
|
| 264 |
<span class="rfc-figure-id" id="rfc.figure.u.1"> </span>
|
| 265 |
<div class="t-pair">
|
| 266 |
<p xml:lang="en" class="t-l-en">
|
| 267 |
<div class="rfc-t-artwork">
|
| 268 |
<table>
|
| 269 |
<thead>
|
| 270 |
<tr>
|
| 271 |
<th class="css-first-child">Sender\Receiver</th>
|
| 272 |
<th>7bit only</th>
|
| 273 |
<th>8bit transparent</th>
|
| 274 |
<th>MIME/ESMTP</th>
|
| 275 |
</tr>
|
| 276 |
</thead>
|
| 277 |
<tbody>
|
| 278 |
<tr>
|
| 279 |
<th>7bit only</th>
|
| 280 |
<td>
|
| 281 |
<span class="rfc-xref">
|
| 282 |
<a href="#s2.i1">(1)</a>
|
| 283 |
</span>
|
| 284 |
</td>
|
| 285 |
<td>
|
| 286 |
<span class="rfc-xref">
|
| 287 |
<a href="#s2.i1">(1)</a>
|
| 288 |
</span>
|
| 289 |
</td>
|
| 290 |
<td>
|
| 291 |
<span class="rfc-xref">
|
| 292 |
<a href="#s2.i1">(1)</a>
|
| 293 |
</span>
|
| 294 |
</td>
|
| 295 |
</tr>
|
| 296 |
<tr>
|
| 297 |
<th>8bit transparent</th>
|
| 298 |
<td>
|
| 299 |
<span class="rfc-xref">
|
| 300 |
<a href="#s2.i2">(2)</a>
|
| 301 |
</span>
|
| 302 |
</td>
|
| 303 |
<td>
|
| 304 |
<span class="rfc-xref">
|
| 305 |
<a href="#s2.i3">(3)</a>
|
| 306 |
</span>
|
| 307 |
</td>
|
| 308 |
<td>
|
| 309 |
<span class="rfc-xref">
|
| 310 |
<a href="#s2.i4">(4)</a>
|
| 311 |
</span>
|
| 312 |
</td>
|
| 313 |
</tr>
|
| 314 |
<tr>
|
| 315 |
<th>MIME/ESMTP</th>
|
| 316 |
<td>
|
| 317 |
<span class="rfc-xref">
|
| 318 |
<a href="#s2.i5">(5)</a>
|
| 319 |
</span>
|
| 320 |
</td>
|
| 321 |
<td>
|
| 322 |
<span class="rfc-xref">
|
| 323 |
<a href="#s2.i5">(5)</a>
|
| 324 |
</span>
|
| 325 |
</td>
|
| 326 |
<td>
|
| 327 |
<span class="rfc-xref">
|
| 328 |
<a href="#s2.i6">(6)</a>
|
| 329 |
</span>
|
| 330 |
</td>
|
| 331 |
</tr>
|
| 332 |
</tbody>
|
| 333 |
</table>
|
| 334 |
</div>
|
| 335 |
</p>
|
| 336 |
<p xml:lang="ja" class="t-l-ja">
|
| 337 |
<div class="rfc-t-artwork">
|
| 338 |
<table>
|
| 339 |
<thead>
|
| 340 |
<tr>
|
| 341 |
<th class="css-first-child">$BAw?.<T(B\$B<u?.<T(B</th>
|
| 342 |
<th>7$B%S%C%H$N$_(B</th>
|
| 343 |
<th>8$B%S%C%HF)2a(B</th>
|
| 344 |
<th>MIME/ESMTP</th>
|
| 345 |
</tr>
|
| 346 |
</thead>
|
| 347 |
<tbody>
|
| 348 |
<tr>
|
| 349 |
<th>7$B%S%C%H$N$_(B</th>
|
| 350 |
<td>
|
| 351 |
<a href="#s2.i1">(1)</a>
|
| 352 |
</td>
|
| 353 |
<td>
|
| 354 |
<a href="#s2.i1">(1)</a>
|
| 355 |
</td>
|
| 356 |
<td>
|
| 357 |
<a href="#s2.i1">(1)</a>
|
| 358 |
</td>
|
| 359 |
</tr>
|
| 360 |
<tr>
|
| 361 |
<th>8$B%S%C%HF)2a(B</th>
|
| 362 |
<td>
|
| 363 |
<a href="#s2.i2">(2)</a>
|
| 364 |
</td>
|
| 365 |
<td>
|
| 366 |
<a href="#s2.i3">(3)</a>
|
| 367 |
</td>
|
| 368 |
<td>
|
| 369 |
<a href="#s2.i4">(4)</a>
|
| 370 |
</td>
|
| 371 |
</tr>
|
| 372 |
<tr>
|
| 373 |
<th>MIME/ESMTP</th>
|
| 374 |
<td>
|
| 375 |
<a href="#s2.i5">(5)</a>
|
| 376 |
</td>
|
| 377 |
<td>
|
| 378 |
<a href="#s2.i5">(5)</a>
|
| 379 |
</td>
|
| 380 |
<td>
|
| 381 |
<a href="#s2.i6">(6)</a>
|
| 382 |
</td>
|
| 383 |
</tr>
|
| 384 |
</tbody>
|
| 385 |
</table>
|
| 386 |
</div>
|
| 387 |
</p>
|
| 388 |
</div>
|
| 389 |
</div>
|
| 390 |
|
| 391 |
<dl class="rfc-list-hanging">
|
| 392 |
<dt id="s2.i1">
|
| 393 |
<a href="#s2.i1" class="self">(1)</a>
|
| 394 |
</dt>
|
| 395 |
<dd>
|
| 396 |
<div class="t-pair">
|
| 397 |
<p xml:lang="en" class="t-l-en">7Bit non-MIME sender to 7bit, MIME, or
|
| 398 |
8bit transparent receiver</p>
|
| 399 |
<p xml:lang="ja" class="t-l-ja">7$B%S%C%HHs(B MIME $BAw?.<T$+$i(B7$B%S%C%H$^$?$O(B
|
| 400 |
MIME, 8$B%S%C%HF)2a<u?.<T$X(B</p>
|
| 401 |
</div>
|
| 402 |
<br class="rfc-vspace"/>
|
| 403 |
<div class="t-pair">
|
| 404 |
<p xml:lang="en" class="t-l-en">
|
| 405 |
This will continue to work unchanged with nationally varient ISO
|
| 406 |
646 or ISO 2022 character set shifting if an external "out of
|
| 407 |
band" agreement exists between the sender and the receiver. A
|
| 408 |
7bit to 8bit/ESMTP gateway need not alter the content of this
|
| 409 |
message.
|
| 410 |
</p>
|
| 411 |
<p xml:lang="ja" class="t-l-ja">
|
| 412 |
ISO 646 $B9q2HHG$d(B ISO 2022 $BJ8;z=89gE>0\$r!"30It!V(Bout of band$B!W9g0U$,Aw<u?.<T4V$GB8:_$9$k>l9g$OJQ99L5$/1?MQ$7B3$1$^$9!#(B7$B%S%C%H$+$i(B8$B%S%C%H(B/SMTP
|
| 413 |
$B$X$N4XLg$O$3$N%a%C%;!<%8$NFbMF$rJQ$($kI,MW$O$"$j$^$;$s!#(B
|
| 414 |
</p>
|
| 415 |
</div>
|
| 416 |
</dd>
|
| 417 |
<ins class="t-note t-l-ja" xml:lang="ja">
|
| 418 |
<span class="t-note-title">$BLuCm(B:</span>
|
| 419 |
<p class="rfc-t" id="rfc.section.2.p.1">Jargon File $B$K$O!"(B $B!V(Bout of band$B!W(B =
|
| 420 |
<q title="Jargon File $B$+$i!V(Bout of band$B!W(B" xml:lang="en">$B!H(Bsometimes
|
| 421 |
used to describe what communications people call $B!F(Bshift characters$B!G(B,
|
| 422 |
such as the <code>ESC</code> that leads control sequences for
|
| 423 |
many terminals$B!I(B</q> $B$H=q$+$l$F$$$^$9!#(B</p>
|
| 424 |
</ins>
|
| 425 |
|
| 426 |
<dt id="s2.i2">
|
| 427 |
<a href="#s2.i2" class="self">(2)</a>
|
| 428 |
</dt>
|
| 429 |
<dd>
|
| 430 |
<div class="t-pair">
|
| 431 |
<p xml:lang="en" class="t-l-en">8bit sender to 7bit non-MIME receiver</p>
|
| 432 |
<p xml:lang="ja" class="t-l-ja">8$B%S%C%HAw?.<T$+$i(B7$B%S%C%HHs(B MIME $B<u?.<T$X(B</p>
|
| 433 |
</div>
|
| 434 |
<br class="rfc-vspace"/>
|
| 435 |
<div class="t-pair">
|
| 436 |
<p xml:lang="en" class="t-l-en">
|
| 437 |
The receiver will receive bit-stripped mail which results in the
|
| 438 |
mis-interpretation of the data and the wrong character being
|
| 439 |
displayed or printed. Mail sent using languages where most
|
| 440 |
characters are in the US-ASCII subset of ISO 8859 may be somewhat
|
| 441 |
readable.
|
| 442 |
</p>
|
| 443 |
<p xml:lang="ja" class="t-l-ja">
|
| 444 |
$B<u?.<T$O!"%G!<%?$N8m2r<a$N7k2L$?$k%S%C%HMn$A%a%$%k$r<u$1<h$j!"4V0c$C$?J8;z$,I=<(!&0u:~$5$l$k$3$H$K$J$k$G$7$g$&!#$[$H$s$I$NJ8;z$,(B
|
| 445 |
ISO 8859 $B$N(B US-ASCII $BItJ,=89gCf$K$"$k8@8l$r;H$C$FAw$i$l$?%a%$%k$O$=$l$J$j$KFI$a$k$+$b$7$l$^$;$s!#(B
|
| 446 |
</p>
|
| 447 |
</div>
|
| 448 |
</dd>
|
| 449 |
|
| 450 |
<dt id="s2.i3">
|
| 451 |
<a href="#s2.i3" class="self">(3)</a>
|
| 452 |
</dt>
|
| 453 |
<dd>
|
| 454 |
<div class="t-pair">
|
| 455 |
<p xml:lang="en" class="t-l-en">8bit transparent sender to 8bit transparent receiver</p>
|
| 456 |
<p xml:lang="ja" class="t-l-ja">8$B%S%C%HF)2aAw?.<T$+$i(B8$B%S%C%HF)2a<u?.<T$X(B</p>
|
| 457 |
</div>
|
| 458 |
<br class="rfc-vspace"/>
|
| 459 |
<div class="t-pair">
|
| 460 |
<p xml:lang="en" class="t-l-en">
|
| 461 |
Will work if an external agreement "out of band" to use a
|
| 462 |
particular character set without tagging exists between the sender
|
| 463 |
and the receiver.
|
| 464 |
</p>
|
| 465 |
<p xml:lang="ja" class="t-l-ja">
|
| 466 |
$BFCDjJ8;z=89g$r;%L5$7$G;HMQ$9$k30It9g0U!V(Bout of band$B!W$,Aw<u?.4V$KB8:_$9$k>l9g$O$&$^$/F/$/$G$7$g$&!#(B
|
| 467 |
</p>
|
| 468 |
</div>
|
| 469 |
</dd>
|
| 470 |
|
| 471 |
<dt id="s2.i4">
|
| 472 |
<a href="#s2.i4" class="self">(4)</a>
|
| 473 |
</dt>
|
| 474 |
<dd>
|
| 475 |
<div class="t-pair">
|
| 476 |
<p xml:lang="en" class="t-l-en">8bit transparent sender to MIME/ESMTP conformant receiver</p>
|
| 477 |
<p xml:lang="ja" class="t-l-ja">8$B%S%C%HF)2aAw?.<T$+$i(B MIME/ESMTP $BE,9g<u?.<T$X(B</p>
|
| 478 |
</div>
|
| 479 |
<br class="rfc-vspace"/>
|
| 480 |
<div class="t-pair">
|
| 481 |
<p xml:lang="en" class="t-l-en">
|
| 482 |
Will work if a reasonable upgrade path is provided via gateways,
|
| 483 |
the indicated character set tag inserted by the gateway is correct
|
| 484 |
and the receiver supports the character set chosen by the sender.
|
| 485 |
This case is the focus of this memo.
|
| 486 |
</p>
|
| 487 |
<p xml:lang="ja" class="t-l-ja">
|
| 488 |
$BJ,JL$"$k3J>e$27PO)$,4XLg7PM3$GDs6!$5$l$F$$$F!"4XLg$,A^F~$9$kJ8;z=89g;%$,@5$7$/$F!"<u?.<T$,Aw?.<T$NA*$s$@J8;z=89g$KBP1~$7$F$$$l$P!"$&$^$/F/$-$^$7$g$&!#$3$N>l9g$,$3$N%a%b$N>GE@$G$9!#(B
|
| 489 |
</p>
|
| 490 |
</div>
|
| 491 |
</dd>
|
| 492 |
|
| 493 |
<dt id="s2.i5">
|
| 494 |
<a href="#s2.i5" class="self">(5)</a>
|
| 495 |
</dt>
|
| 496 |
<dd>
|
| 497 |
<div class="t-pair">
|
| 498 |
<p xml:lang="en" class="t-l-en">MIME/ESMTP sender to non-MIME 7bit receiver</p>
|
| 499 |
<p xml:lang="ja" class="t-l-ja">MIME/ESMTP $BAw?.<T$+$iHs(B MIME 7$B%S%C%H<u?.<T$X(B</p>
|
| 500 |
</div>
|
| 501 |
<br class="rfc-vspace"/>
|
| 502 |
<div class="t-pair">
|
| 503 |
<p xml:lang="en" class="t-l-en">
|
| 504 |
Because the ESMTP/MIME sender cannot know if the receiver will
|
| 505 |
understand 8bits, the sender will encode the text into base-64 or
|
| 506 |
quoted-printable which may be considered "garbled" by the
|
| 507 |
receiver. To provide a useful downgrade path the gateway must
|
| 508 |
have some knowledge about the capabilities of the receiver. When
|
| 509 |
the character set can be clearly identified, techniques like the
|
| 510 |
menmonic MNEM encoding described in RFC 1345 may be helpful in
|
| 511 |
this case.
|
| 512 |
</p>
|
| 513 |
<p xml:lang="ja" class="t-l-ja">
|
| 514 |
ESMTP/MIME $BAw?.<T$O<u?.<T$,(B8$B%S%C%H$rM}2r$9$k$+$I$&$+CN$jF@$J$$$N$G!"Aw?.<T$OJ8$r(B
|
| 515 |
base-64 $B$+<u?.<T$K!VJ8;z2=$1$7$?!W$H;W$o$l$k$+$b$7$l$J$$(B
|
| 516 |
quoted-printable $B$GId9f2=$9$k$G$7$g$&!#M-MQ$J3J2<$27PO)$rDs6!$9$k$K$O4XLg$O<u?.<T$NM}2rG=NO$K$D$$$F$NCN<1$rM-$9$kI,MW$,$"$j$^$9!#J8;z=89g$,L@3N$K<1JL=PMh$k;~$O!"(B
|
| 517 |
<a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1345" title="RFC 1345">RFC 1345</a> $B$G@bL@$5$l$F$$$k5-K!(B MNEM
|
| 518 |
$BId9f2=$NMM$J<jK!$,$3$N>l9g$K$OM-MQ$+$b$7$l$^$;$s!#(B
|
| 519 |
</p>
|
| 520 |
</div>
|
| 521 |
</dd>
|
| 522 |
|
| 523 |
<dt id="s2.i6">
|
| 524 |
<a href="#s2.i6" class="self">(6)</a>
|
| 525 |
</dt>
|
| 526 |
<dd>
|
| 527 |
<div class="t-pair">
|
| 528 |
<p xml:lang="en" class="t-l-en">MIME/ESMTP sender to MIME/ESMTP receiver</p>
|
| 529 |
<p xml:lang="ja" class="t-l-ja">MIME/ESMTP $BAw?.<T$+$i(B MIME/ESMTP $B<u?.<T$X(B</p>
|
| 530 |
</div>
|
| 531 |
<br class="rfc-vspace"/>
|
| 532 |
<div class="t-pair">
|
| 533 |
<p xml:lang="en" class="t-l-en">
|
| 534 |
Interoperability will be attained provided the receiver supports
|
| 535 |
the character set chosen by the sender.
|
| 536 |
</p>
|
| 537 |
<p xml:lang="ja" class="t-l-ja">$BAj8_DL?.@-$OAw?.<T$,A*Br$7$?J8;z=89g$K<u?.<T$,BP1~$9$k$3$H$K$h$jK~$?$5$l$^$9!#(B</p>
|
| 538 |
</div>
|
| 539 |
</dd>
|
| 540 |
</dl>
|
| 541 |
</div>
|
| 542 |
|
| 543 |
<div class="rfc-section" id="rfc.section.3">
|
| 544 |
<div class="t-pair t-heading">
|
| 545 |
<h1 xml:lang="en" class="t-l-en">3. Upgrade Path from 8bit Transparent to ESMTP/MIME</h1>
|
| 546 |
<h1 xml:lang="ja" class="t-l-ja">3.
|
| 547 |
8$B%S%C%HF)2a$+$i(B ESMTP/MIME $B$X$N3J>e$27PO)(B</h1>
|
| 548 |
</div>
|
| 549 |
|
| 550 |
<div class="rfc-t" id="rfc.section.3.p.1">
|
| 551 |
<div class="t-pair">
|
| 552 |
<p xml:lang="en" class="t-l-en">
|
| 553 |
A gateway which has been upgraded to support Extended SMTP may
|
| 554 |
upgrade an 8bit message received to MIME. This is consistent with
|
| 555 |
the requirement that all 8bit mail sent by ESMTP be encoded in MIME.
|
| 556 |
The upgrade should be done using the best available information.
|
| 557 |
</p>
|
| 558 |
<p xml:lang="ja" class="t-l-ja">
|
| 559 |
$B3HD%(B SMTP $B$KBP1~$9$k$h$&3J>e$2$9$k4XLg$O!"<u?.$7$?(B8$B%S%C%H!&%a%C%;!<%8$r(B
|
| 560 |
MIME $B$K3J>e$2$7$F9=$$$^$;$s!#$3$l$O(B ESMTP $B$GAw?.$5$l$k(B8$B%S%C%H!&%a%$%k$OA4$F(B
|
| 561 |
MIME $B$GId9f2=$5$l$F$$$J$1$l$P$J$i$J$$$H$$$&MW7o$rK~$?$7$^$9!#3J>e$2$O0lHVMxMQ2DG=$J>pJs$r;H$C$F9T$&$Y$-$G$9!#(B
|
| 562 |
</p>
|
| 563 |
</div>
|
| 564 |
</div>
|
| 565 |
|
| 566 |
<div class="rfc-t" id="rfc.section.3.p.2">
|
| 567 |
<div class="t-pair">
|
| 568 |
<p xml:lang="en" class="t-l-en">
|
| 569 |
A site may "upgrade" to MIME en-masse by implementing MIME conversion
|
| 570 |
for all messages leaving the site. For text messages, the body can
|
| 571 |
be converted by adding a MIME-version header and a Content-Type:
|
| 572 |
Text/Plain with the character set in use in the site, provided the
|
| 573 |
site uses a single character set.
|
| 574 |
</p>
|
| 575 |
<p xml:lang="ja" class="t-l-ja">
|
| 576 |
$B%5%$%H$O!"%5%$%H$rN%$l$kA4$F$N%a%C%;!<%8$r!"(B
|
| 577 |
MIME $B$r<BAu$9$k$3$H$G$^$H$a$F(B MIME $B$K!V3J>e$2!W$7$F$b9=$$$^$;$s!#%F%-%9%H!&%a%C%;!<%8$K$D$$$F$O!"K\BN$O(B
|
| 578 |
MIME-version $BF,$H(B Content-Type: Text/Plain
|
| 579 |
$B$K%5%$%HFb$G;H$o$l$F$$$kJ8;z=89g$r$D$1$k$3$H$G!"%5%$%H$,C10lJ8;z=89g$r;H$C$F$$$k>l9g$OJQ49=PMh$^$9!#(B
|
| 580 |
</p>
|
| 581 |
</div>
|
| 582 |
</div>
|
| 583 |
|
| 584 |
<div class="rfc-t" id="rfc.section.3.p.3">
|
| 585 |
<div class="t-pair">
|
| 586 |
<p xml:lang="en" class="t-l-en">
|
| 587 |
An appropriate Content-Transfer-Encoding header line must be added to
|
| 588 |
indicate any encoding that may be necessary.
|
| 589 |
</p>
|
| 590 |
<p xml:lang="ja" class="t-l-ja">
|
| 591 |
$BE,@Z$J(B Content-Transfer-Encoding
|
| 592 |
$BF,9T$r!"I,MW$+$b$7$l$J$$Id9f2=$r<($9$N$K2C$($J$1$l$P$J$j$^$;$s!#(B
|
| 593 |
</p>
|
| 594 |
</div>
|
| 595 |
</div>
|
| 596 |
|
| 597 |
<div class="t-example">
|
| 598 |
<div class="t-title t-pair">
|
| 599 |
<div class="t-l-en" xml:lang="en">Example: </div>
|
| 600 |
<div class="t-l-ja" xml:lang="ja">$BNc(B: </div>
|
| 601 |
</div>
|
| 602 |
<pre xml:space="preserve">
|
| 603 |
MIME-Version: 1.0
|
| 604 |
Content-Type: Text/Plain; Charset = ISO-8859-1
|
| 605 |
Content-Transfer-Encoding: 8bit
|
| 606 |
</pre>
|
| 607 |
</div>
|
| 608 |
|
| 609 |
<div class="rfc-t" id="rfc.section.3.p.4">
|
| 610 |
<div class="t-pair">
|
| 611 |
<p xml:lang="en" class="t-l-en">
|
| 612 |
If no information about the character set in use is available, the
|
| 613 |
gateway should upgrade the content by using the character set
|
| 614 |
"unknown-8bit". The unknown-8bit value of the charset parameter
|
| 615 |
indicates only that no reliable information about the character
|
| 616 |
set(s) used in the message was available.
|
| 617 |
</p>
|
| 618 |
<p xml:lang="ja" class="t-l-ja">
|
| 619 |
$B;HMQ$5$l$F$$$kJ8;z=89g$K$D$$$F$N>pJs$,L5$$>l9g$O!"4XLg$OFbMF$rJ8;z=89g(B
|
| 620 |
"unknown-8bit" $B$r;H$C$F3J>e$2$9$k$Y$-$G$9!#(B charset
|
| 621 |
$B%Q%i%a!<%?!<$N(B unknown-8bit
|
| 622 |
$BCM$O%a%C%;!<%8$K;H$o$l$F$$$kJ8;z=89g$K$D$$$F$N3N<B$J>pJs$rF@$k$3$H$,=PMh$J$+$C$?$3$H$N$_$r<($7$^$9!#(B
|
| 623 |
</p>
|
| 624 |
</div>
|
| 625 |
</div>
|
| 626 |
|
| 627 |
<div class="rfc-t" id="rfc.section.3.p.5">
|
| 628 |
<div class="t-pair">
|
| 629 |
<p xml:lang="en" class="t-l-en">
|
| 630 |
If a message body has been upgraded to MIME, the RFC 822 headers
|
| 631 |
containing non US-ASCII characters must be upgraded to conform with
|
| 632 |
the header encoding rules of RFC1342. A gateway should recode all
|
| 633 |
unstructered header fields as well as RFC 822 "comment"s and
|
| 634 |
"phrase"s according to the rules of RFC 1342. There is no equivalent
|
| 635 |
in RFC 1342 to the "8bit" Content-Transfer-Encoding value for message
|
| 636 |
bodies so all 8bit header text must be transformed according to
|
| 637 |
either the "B" or the "Q" encoding method. For ISO 8859 character
|
| 638 |
sets, the "Q" encoding will generally result in somewhat readable
|
| 639 |
headers.
|
| 640 |
</p>
|
| 641 |
<p xml:lang="ja" class="t-l-ja">
|
| 642 |
$B%a%C%;!<%8K\BN$,(B MIME $B$K3J>e$2$5$l$k>l9g!"Hs(B US-ASCII
|
| 643 |
$BJ8;z$r4^$`(B <a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:822" title="RFC 822">RFC 822</a> $BF,$O(B
|
| 644 |
RFC1342 $B$NF,Id9f2=5,B'$KE,9g$9$k$h$&$7$J$1$l$P$J$j$^$;$s!#4XLg$OA4$F$NHs9=B$2=F,NN0h$H(B
|
| 645 |
RFC 822 "comment" $B$H(B "phrase" $B$r(B RFC 1342
|
| 646 |
$B$N5,B'$K=>$$:FId9f2=$9$k$Y$-$G$9!#%a%C%;!<%8K\BN$N(B "8bit"
|
| 647 |
$BFbMFE>AwId9f2=CM$KAjEv$9$k$b$N$O(B RFC 1342
|
| 648 |
$B$K$OL5$$$N$G!"A4$F$N(B8$B%S%C%HF,J8$O(B "B" $BId9f2=J}<0$^$?$O(B "Q"
|
| 649 |
$BId9f2=J}<0$GId9f2=$7$J$1$l$P$J$j$^$;$s!#(B ISO 8859 $BJ8;z=89g$K$O!"(B
|
| 650 |
"Q" $BId9f2=$r;H$&$H!"DL>o$d$d2DFI$JF,$H$J$j$^$9!#(B
|
| 651 |
</p>
|
| 652 |
</div>
|
| 653 |
</div>
|
| 654 |
|
| 655 |
<div class="rfc-figure">
|
| 656 |
<span class="rfc-figure-id" id="rfc.figure.u.2"> </span>
|
| 657 |
<div class="rfc-preamble">
|
| 658 |
<div class="t-pair">
|
| 659 |
<p xml:lang="en" class="t-l-en">
|
| 660 |
Trace information should be added to the document with a convert
|
| 661 |
clause: "rfc822-to-8bit", "rfc822-to-base-64" or "rfc822-to-quoted-
|
| 662 |
printable" e.g.,
|
| 663 |
</p>
|
| 664 |
<p xml:lang="ja" class="t-l-ja">
|
| 665 |
$BDI@W>pJs$r<!$NNc$N$h$&$KJQ49(B (convert) $B>r9`(B "rfc822-to-8bit",
|
| 666 |
"rfc822-to-base-64", "rfc822-to-quoted-printable"
|
| 667 |
$B$D$-$GJ8=q$KDI2C$9$k$Y$-$G$9!#(B
|
| 668 |
</p>
|
| 669 |
</div>
|
| 670 |
</div>
|
| 671 |
|
| 672 |
<pre class="rfc-artwork" xml:space="preserve">
|
| 673 |
Received: from dbc.mtview.ca.us by dbc.mtview.ca.us
|
| 674 |
convert rfc822-to-8bit; Tue, 01 Sep 1992 01:18:00 -0700
|
| 675 |
</pre>
|
| 676 |
</div>
|
| 677 |
</div>
|
| 678 |
|
| 679 |
<div class="rfc-section">
|
| 680 |
<div class="t-pair t-heading">
|
| 681 |
<h1 xml:lang="en" class="t-l-en">Appendix $B!=(B The $B!H(Bunknown-8bit$B!I(B Character Set</h1>
|
| 682 |
<h1 xml:lang="ja" class="t-l-ja">$BImB0=q(B $B!=(B $B!V(Bunknown-8bit$B!WJ8;z=89g(B</h1>
|
| 683 |
</div>
|
| 684 |
|
| 685 |
<div class="rfc-t" id="rfc.section.4.p.1">
|
| 686 |
<div class="t-pair">
|
| 687 |
<p xml:lang="en" class="t-l-en">
|
| 688 |
This section defines a "charset" parameter, for use in a MIME
|
| 689 |
Content-Type field.
|
| 690 |
</p>
|
| 691 |
<p xml:lang="ja" class="t-l-ja">
|
| 692 |
$B$3$N@a$G$O(B MIME Content-Type $BNN0h$G;H$&(B "charset"
|
| 693 |
$B%Q%i%a!<%?!<$rDj5A$7$^$9!#(B
|
| 694 |
</p>
|
| 695 |
</div>
|
| 696 |
</div>
|
| 697 |
|
| 698 |
<div class="rfc-t" id="rfc.section.4.p.2">
|
| 699 |
<div class="t-pair">
|
| 700 |
<p xml:lang="en" class="t-l-en">
|
| 701 |
A special purpose character set called "unknown-8bit" is defined to
|
| 702 |
be an unknown 8bit character set, encoded into a sequence of octets.
|
| 703 |
It can be used as a label for any character set from any language,
|
| 704 |
using any encoding. It must not be further defined.
|
| 705 |
</p>
|
| 706 |
<p xml:lang="ja" class="t-l-ja">
|
| 707 |
"unknown-8bit" $B$H$$$&FC<lL\E*J8;z=89g$r!"%*%/%F%C%HNs$KId9f2=$5$l$?L$CN$N(B8$B%S%C%HJ8;z=89gMQ$KDj5A$7$^$9!#$3$l$O$$$+$J$k8@8l$G$$$+$J$kId9f2=$rMQ$$$k$$$+$J$kJ8;z=89g$K$b;%$H$7$F;H$&$3$H$,=PMh$^$9!#$3$l0J>e$ODj5A$7$^$;$s!#(B
|
| 708 |
</p>
|
| 709 |
</div>
|
| 710 |
</div>
|
| 711 |
|
| 712 |
<div class="rfc-t" id="rfc.section.4.p.3">
|
| 713 |
<div class="t-pair">
|
| 714 |
<p xml:lang="en" class="t-l-en">
|
| 715 |
The use of this token in a "charset=" field of a message indicates
|
| 716 |
that nothing is known about the character set used. This marker is
|
| 717 |
intended for use by non-MIME to MIME gateways; specifically in those
|
| 718 |
which translate from SMTP to 8bit ESMTP/MIME.
|
| 719 |
</p>
|
| 720 |
<p xml:lang="ja" class="t-l-ja">
|
| 721 |
$B$3$N;z6g$r%a%C%;!<%8$N(B "charset="
|
| 722 |
$BNN0h$G;H$&$3$H$G!";H$o$l$F$$$kJ8;z=89g$K$D$$$FA4$/$b$C$FITL@$G$"$k$3$H$r<($7$^$9!#$3$N0u$OHs(B MIME $B$+$i(B MIME $B$X$N4XLg!"6qBNE*$K$O(B SMTP
|
| 723 |
$B$+$i(B8$B%S%C%H(B ESMTP/MIME $B$KJQ49$9$k4XLg$G;H$&$3$H$r0U?^$7$F$$$^$9!#(B
|
| 724 |
</p>
|
| 725 |
</div>
|
| 726 |
</div>
|
| 727 |
|
| 728 |
<div class="rfc-t" id="rfc.section.4.p.4">
|
| 729 |
<div class="t-pair">
|
| 730 |
<p xml:lang="en" class="t-l-en">
|
| 731 |
This character set is not intended to be used by mail composers.
|
| 732 |
It is assumed that the mail composer knows the character set in
|
| 733 |
use and will mark it with a character set value as specified in
|
| 734 |
<span class="rfc-xref">
|
| 735 |
<a href="#refs.RFC1341" title="Multipurpose Internet Mail Extensions">[1]</a>
|
| 736 |
</span>, as amended by current Assigned
|
| 737 |
Numbers documents <span class="rfc-xref">
|
| 738 |
<a href="#refs.STD2" title="Assigned Numbers">[6]</a>
|
| 739 |
</span>.
|
| 740 |
</p>
|
| 741 |
<p xml:lang="ja" class="t-l-ja">
|
| 742 |
$B$3$NJ8;z=89g$O%a%$%k:n@.<T$,;H$&$3$H$O0U?^$7$F$$$^$;$s!#%a%$%k:n@.<T$O;HMQ$9$kJ8;z=89g$rCN$C$F$$$F!"(B
|
| 743 |
<a href="#refs.RFC1341" title="$BB?L\E*(B Internet $B%a%$%k3HD%(B">[1]</a> $B$G5,Dj$5$l$F8=9T$N3dEvHV9fJ8=q(B
|
| 744 |
<a href="#refs.STD2" title="$B3dEvHV9f(B">[6]</a>
|
| 745 |
$B$G2~D{$5$l$?J8;z=89gCM$G0u$r$D$1$k$HA[Dj$7$F$$$^$9!#(B
|
| 746 |
</p>
|
| 747 |
</div>
|
| 748 |
</div>
|
| 749 |
|
| 750 |
<div class="rfc-t" id="rfc.section.4.p.5">
|
| 751 |
<div class="t-pair">
|
| 752 |
<p xml:lang="en" class="t-l-en">
|
| 753 |
The use of the "unknown-8bit" label is intended only by mail gateway
|
| 754 |
agents which cannot determine via out-of-band information the
|
| 755 |
intended character set.
|
| 756 |
</p>
|
| 757 |
<p xml:lang="ja" class="t-l-ja">
|
| 758 |
"unknown-8bit" $B;%$N;HMQ$O!"(B out of band
|
| 759 |
$B>pJs$K$h$j0U?^$5$l$?J8;z=89g$r7hDj=PMh$J$$%a%$%k4XLgBeM}<T$K$h$j$N$_;H$o$l$k$3$H$rA[Dj$7$F$$$^$9!#(B
|
| 760 |
</p>
|
| 761 |
</div>
|
| 762 |
</div>
|
| 763 |
|
| 764 |
<div class="rfc-t" id="rfc.section.4.p.6">
|
| 765 |
<div class="t-pair">
|
| 766 |
<p xml:lang="en" class="t-l-en">
|
| 767 |
The interpretation of the "unknown-8bit" is up to the mail reader.
|
| 768 |
It is assumed that in many cases the human user will be able to
|
| 769 |
interpret the information and choose an appropriate character set or
|
| 770 |
pre-processor.
|
| 771 |
</p>
|
| 772 |
<p xml:lang="ja" class="t-l-ja">
|
| 773 |
"unknown-8bit" $B$N2r<a$O%a%$%k!&%j!<%@!<$K0Q$M$i$l$^$9!#B?$/$N>l9g$G$O?M4VMxMQ<T$,>pJs$r2r<a$7$FE,@Z$JJ8;z=89g$"$k$$$OA0=hM}4o$rA*Br$G$-$k$H;W$o$l$^$9!#(B
|
| 774 |
</p>
|
| 775 |
</div>
|
| 776 |
</div>
|
| 777 |
|
| 778 |
</div>
|
| 779 |
|
| 780 |
<div class="rfc-section">
|
| 781 |
<div class="t-pair t-heading">
|
| 782 |
<h1 xml:lang="en" class="t-l-en">Acknowledgements</h1>
|
| 783 |
<h1 xml:lang="ja" class="t-l-ja">$B<U<-(B</h1>
|
| 784 |
</div>
|
| 785 |
<div class="rfc-t" id="rfc.section.5.p.1">
|
| 786 |
<div class="t-pair">
|
| 787 |
<p xml:lang="en" class="t-l-en">
|
| 788 |
This document originated as a hallway conversation between
|
| 789 |
Ned Freed, Neil Katin, and the author. Substantive input
|
| 790 |
was received from Jonathan Laventhol, Craig Everhart,
|
| 791 |
Olle Jarnefors, and Olafur Gudmundsson. The document was
|
| 792 |
refined with the input of many participants in the IETF SMTP
|
| 793 |
Extensions Working Group.
|
| 794 |
</p>
|
| 795 |
<p xml:lang="ja" class="t-l-ja">
|
| 796 |
$B$3$NJ8=q$O(B Ned Freed, Neil Katin $B$HCx<T$N0f8MC<2q5D$+$i@8$^$l$^$7$?!#(B
|
| 797 |
Jonathan Laventhol, Craig Everhart,
|
| 798 |
Olle Jarnefors, Olafur Gudmundsson $B$,:2$r?a$-9~$s$G$/$l$^$7$?!#$3$NJ8=q$O(B
|
| 799 |
IETF SMTP $B3HD%:n6HIt2q$N;22C<T$N0U8+$K$h$j@:O#$5$l$^$7$?!#(B
|
| 800 |
</p>
|
| 801 |
</div>
|
| 802 |
</div>
|
| 803 |
</div>
|
| 804 |
|
| 805 |
<div class="rfc-section" id="rfc.references.References">
|
| 806 |
<div class="t-pair t-heading">
|
| 807 |
<h1 xml:lang="en" class="t-l-en">References</h1>
|
| 808 |
<h1 xml:lang="ja" class="t-l-ja">$B;29MJ88%(B</h1>
|
| 809 |
</div>
|
| 810 |
<dl>
|
| 811 |
<dt id="refs.RFC1341">[1]</dt>
|
| 812 |
<dd>$B!X(B<cite>
|
| 813 |
<a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1341" title="URI: <http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1341>">Multipurpose Internet Mail Extensions</a>
|
| 814 |
</cite>$B!Y(B<span class="t-pair">
|
| 815 |
<span xml:lang="ja" class="t-l-ja">, $B!X(B<cite>$BB?L\E*(B Internet $B%a%$%k3HD%(B</cite>$B!Y(B</span>
|
| 816 |
</span>, Borenstein, N., Freed, N., RFC
|
| 817 |
 1341$B!#(B</dd>
|
| 818 |
<dt id="refs.RFC1342">[2]</dt>
|
| 819 |
<dd>$B!X(B<cite>
|
| 820 |
<a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1342" title="URI: <http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1342>">Representation of Non-ASCII Text in Internet Message Headers</a>
|
| 821 |
</cite>$B!Y(B<span class="t-pair">
|
| 822 |
<span xml:lang="ja" class="t-l-ja">, $B!X(B<cite>$BHs(B ASCII $BJ8$N(B Internet $B%a%C%;!<%8F,$K$*$1$kI=8=(B</cite>$B!Y(B</span>
|
| 823 |
</span>, Moore, K., RFC
|
| 824 |
 1342$B!#(B</dd>
|
| 825 |
<dt id="refs.RFC1425">[3]</dt>
|
| 826 |
<dd>$B!X(B<cite>
|
| 827 |
<a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1425" title="URI: <http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1425>">SMTP Service Extensions</a>
|
| 828 |
</cite>$B!Y(B<span class="t-pair">
|
| 829 |
<span xml:lang="ja" class="t-l-ja">, $B!X(B<cite>SMTP $B%5!<%S%93HD%(B</cite>$B!Y(B</span>
|
| 830 |
</span>, Klensin, J., WG Chair, Freed, N., Editor, Rose, M., Stefferud, E., Crocker, D., RFC
|
| 831 |
 1425$B!#(B</dd>
|
| 832 |
<dt id="refs.RFC1426">[4]</dt>
|
| 833 |
<dd>$B!X(B<cite>
|
| 834 |
<a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1426" title="URI: <http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1426>">SMTP Service Extensions for 8bit
|
| 835 |
MIMEtransport</a>
|
| 836 |
</cite>$B!Y(B<span class="t-pair">
|
| 837 |
<span xml:lang="ja" class="t-l-ja">, $B!X(B<cite>8$B%S%C%H(B MIME $BE>AwMQ(B SMTP $B%5!<%S%93HD%(B</cite>$B!Y(B</span>
|
| 838 |
</span>, Klensin, J., WG Chair, Freed, N., Editor, Rose, M., Stefferud, E., Crocker, D., RFC
|
| 839 |
 1426$B!#(B</dd>
|
| 840 |
<dt id="refs.ASCII">[5]</dt>
|
| 841 |
<dd>$B!X(B<cite>Coded Character Set$B!=!=(B7-Bit American Standard Code
|
| 842 |
for Information Interchange</cite>$B!Y(B<span class="t-pair">
|
| 843 |
<span xml:lang="ja" class="t-l-ja">, $B!X(B<cite>$BId9f2=J8;z=89g!=!=(B7$B%S%C%H$N>pJs8r49MQ0!JFMx2CI8=`Id9f(B</cite>$B!Y(B</span>
|
| 844 |
</span>, ANSI
|
| 845 |
 X3.4-1986$B!#(B</dd>
|
| 846 |
<dt id="refs.STD2">[6]</dt>
|
| 847 |
<dd>$B!X(B<cite>
|
| 848 |
<a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1340" title="URI: <http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:1340>">Assigned Numbers</a>
|
| 849 |
</cite>$B!Y(B<span class="t-pair">
|
| 850 |
<span xml:lang="ja" class="t-l-ja">, $B!X(B<cite>$B3dEvHV9f(B</cite>$B!Y(B</span>
|
| 851 |
</span>, Reynolds, J., Postel, J., STD
|
| 852 |
 2, RFC
|
| 853 |
 1340$B!#(B</dd>
|
| 854 |
</dl>
|
| 855 |
</div>
|
| 856 |
|
| 857 |
|
| 858 |
<div class="rfc-section">
|
| 859 |
<div class="t-pair t-heading">
|
| 860 |
<h1 xml:lang="en" class="t-l-en">Security Considerations</h1>
|
| 861 |
<h1 xml:lang="ja" class="t-l-ja">$B0BA4@-$K4X$7$F(B</h1>
|
| 862 |
</div>
|
| 863 |
<p class="rfc-t" id="rfc.section.6.p.1">
|
| 864 |
<div class="t-pair">
|
| 865 |
<p xml:lang="en" class="t-l-en">Security issues are not discussed in this memo.</p>
|
| 866 |
<p xml:lang="ja" class="t-l-ja">$B0BA4@-LdBj$O$3$N%a%b$G$O<h$j07$C$F$$$^$;$s!#(B</p>
|
| 867 |
</div>
|
| 868 |
</p>
|
| 869 |
</div>
|
| 870 |
|
| 871 |
<div id="rfc-authors" class="rfc-section">
|
| 872 |
<div id="rfc.authors" class="t-pair t-heading">
|
| 873 |
<h1 xml:lang="en" class="t-l-en">Author's Address</h1>
|
| 874 |
<h1 xml:lang="ja" class="t-l-ja">$BCx<T$NO"Mm@h(B</h1>
|
| 875 |
</div>
|
| 876 |
<ul class="rfc-author">
|
| 877 |
<li class="rfc-author-fullname">Greg Vaudreuil</li>
|
| 878 |
<li class="rfc-organization">Corporation for National Research Initiatives</li>
|
| 879 |
<li class="rfc-street">1895 Preston White Drive, Suite 100</li>
|
| 880 |
<li class="rfc-city">Reston</li>
|
| 881 |
<li class="rfc-region">VA</li>
|
| 882 |
<li class="rfc-code">22091</li>
|
| 883 |
<li class="rfc-country">USA</li>
|
| 884 |
<li class="rfc-phone">$BEEOC(B: (703) 620-8990</li>
|
| 885 |
<li class="rfc-email">$BEE;R%a%$%k(B: <<a href="mailto:GVaudre@CNRI.Reston.VA.US">GVaudre@CNRI.Reston.VA.US</a>></li>
|
| 886 |
</ul>
|
| 887 |
</div>
|
| 888 |
<ins id="rfc-translators-note" class="t-note t-l-ja" xml:lang="ja">
|
| 889 |
<div class="rfc-section" id="t-change">
|
| 890 |
<h1>$BK]Lu$NJQ99MzNr(B</h1>
|
| 891 |
<dl>
|
| 892 |
<dt>2002-05-08 <a href="mailto:w@suika.fam.cx" title="$BEE;R%a%$%k(B: <w@suika.fam.cx>">$B$o$+$P(B</a>
|
| 893 |
</dt>
|
| 894 |
<dd>
|
| 895 |
<ul>
|
| 896 |
<li>
|
| 897 |
<a href="http://suika.fam.cx/uri-res/N2L?urn:ietf:rfc:2629" title="RFC 2629">RFC 2629</a> $B$G%^!<%/IU$1!#(B</li>
|
| 898 |
<li>$BK]Lu40N;!#(B</li>
|
| 899 |
</ul>
|
| 900 |
</dd>
|
| 901 |
</dl>
|
| 902 |
</div>
|
| 903 |
<div class="rfc-section" id="rfc-t-copyright">
|
| 904 |
<h1>$BLuJ8$K$D$$$F$NCx:n8"@<L@(B</h1>
|
| 905 |
<ul>
|
| 906 |
<li>Copyright © $B$o$+$P(B (2002)$B!#A48"J]N1!#(B</li>
|
| 907 |
</ul>
|
| 908 |
<p>$B$3$NK]LuJ8$O!"<+M3$KJ#@=!&G[I[!&2~JQ$7$F9=$$$^$;$s!#(B
|
| 909 |
(rfc-copyright-story $B$b;2>H$7$F2<$5$$!#(B)</p>
|
| 910 |
</div>
|
| 911 |
</ins>
|
| 912 |
</body>
|
| 913 |
</html>
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