intro.ps

早期freebsd实现

(Other macros are unused internally)5.848 F 3.348(,a)-.65 G .848
(nd can be used as shorthand in the)361.142 108 R(con\214guration \214le.)117
120 Q F0 2.5(3.7.2. Header)102 144 R(declarations)2.5 E F1 .355
(Header declarations inform)142 160.2 R/F2 10/Times-Italic@0 SF(sendmail)2.854
E F1 .354(of the format of kno)2.854 F .354(wn header lines.)-.25 F(Kno)5.354 E
.354(wledge of)-.25 F 2.5(af)117 172.2 S .5 -.25(ew h)127.27 172.2 T
(eader lines is b).25 E(uilt into)-.2 E F2(sendmail)2.5 E F1 2.5(,s)C
(uch as the \231From:\232 and \231Date:\232 lines.)284.59 172.2 Q 1.201(Most c\
on\214gured headers will be automatically inserted in the outgoing message if \
the)142 188.4 R(y)-.15 E(don')117 200.4 Q 2.5(te)-.18 G
(xist in the incoming message.)144.72 200.4 Q
(Certain headers are suppressed by some mailers.)5 E F0 2.5(3.7.3. Mailer)102
224.4 R(declarations)2.5 E F1 1.756(Mailer declarations tell)142 240.6 R F2
(sendmail)4.256 E F1 1.756(of the v)4.256 F 1.756(arious mailers a)-.25 F -.25
(va)-.2 G 1.756(ilable to it.).25 F 1.755(The de\214nition)6.755 F .119
(speci\214es the internal name of the mailer)117 252.6 R 2.619(,t)-.4 G .12
(he pathname of the program to call, some \215ags associ-)285.183 252.6 R 2.036
(ated with the mailer)117 264.6 R 4.536(,a)-.4 G 2.036(nd an ar)213.894 264.6 R
2.036(gument v)-.18 F 2.036(ector to be used on the call; this v)-.15 F 2.035
(ector is macro-)-.15 F -.15(ex)117 276.6 S(panded before use.).15 E F0 2.5
(3.7.4. Addr)102 300.6 R(ess r)-.18 E(ewriting rules)-.18 E F1 .458
(The heart of address parsing in)142 316.8 R F2(sendmail)2.959 E F1 .459
(is a set of re)2.959 F .459(writing rules.)-.25 F .459(These are an ordered)
5.459 F .561(list of pattern-replacement rules, \(some)117 328.8 R .561
(what lik)-.25 F 3.061(eap)-.1 G .561(roduction system, e)328.867 328.8 R .56
(xcept that order is criti-)-.15 F 1.905
(cal\), which are applied to each address.)117 340.8 R 1.905(The address is re)
6.905 F 1.906(written te)-.25 F 1.906(xtually until it is either)-.15 F(re)117
352.8 Q .308(written into a special canonical form \(i.e., a \(mailer)-.25 F
2.807(,h)-.4 G .307(ost, user\) 3-tuple, such as {arpanet, usc-)342.118 352.8 R
.64(isif, postel} representing the address \231postel@usc-isif\232\), or it f)
117 364.8 R .641(alls of)-.1 F 3.141(ft)-.25 G .641(he end.)406.466 364.8 R
.641(When a pattern)5.641 F(matches, the rule is reapplied until it f)117 376.8
Q(ails.)-.1 E 1.222
(The con\214guration \214le also supports the editing of addresses into dif)142
393 R 1.221(ferent formats.)-.25 F -.15(Fo)6.221 G(r).15 E -.15(ex)117 405 S
(ample, an address of the form:).15 E(ucsfcgl!tef)157 421.2 Q
(might be mapped into:)117 437.4 Q([e-mail])157 453.6 Q
(to conform to the domain syntax.)117 469.8 Q -.35(Tr)5 G
(anslations can also be done in the other direction.).35 E F0 2.5
(3.7.5. Option)102 493.8 R(setting)2.5 E F1 1.168(There are se)142 510 R -.15
(ve)-.25 G 1.169(ral options that can be set from the con\214guration \214le.)
.15 F 1.169(These include the)6.169 F(pathnames of v)117 522 Q
(arious support \214les, timeouts, def)-.25 E(ault modes, etc.)-.1 E F0 2.5
(4. COMP)72 546 R(ARISON WITH O)-.74 E(THER MAILERS)-.4 E 2.5(4.1. Deli)87 570
R -.1(ve)-.1 G(rmail).1 E F2(Sendmail)127 586.2 Q F1(is an outgro)2.5 E(wth of)
-.25 E F2(delivermail)2.5 E F1 5(.T)C(he primary dif)301.18 586.2 Q
(ferences are:)-.25 E 12.5(\(1\) Con\214guration)107 602.4 R .273
(information is not compiled in.)2.773 F .272(This change simpli\214es man)
5.273 F 2.772(yo)-.15 G 2.772(ft)445.686 602.4 S .272(he problems)454.568 602.4
R(of mo)133.66 614.4 Q(ving to other machines.)-.15 E(It also allo)5 E
(ws easy deb)-.25 E(ugging of ne)-.2 E 2.5(wm)-.25 G(ailers.)413.89 614.4 Q
12.5(\(2\) Address)107 630.6 R .681(parsing is more \215e)3.181 F 3.182
(xible. F)-.15 F .682(or e)-.15 F(xample,)-.15 E F2(delivermail)3.182 E F1 .682
(only supported one g)3.182 F(ate)-.05 E -.1(wa)-.25 G 3.182(yt).1 G(o)499
630.6 Q(an)133.66 642.6 Q 2.817(yn)-.15 G(etw)155.767 642.6 Q .317
(ork, whereas)-.1 F F2(sendmail)2.817 E F1 .317(can be sensiti)2.817 F .616
-.15(ve t)-.25 H 2.816(oh).15 G .316(ost names and reroute to dif)345.224 642.6
R .316(ferent g)-.25 F(ate-)-.05 E -.1(wa)133.66 654.6 S(ys.).1 E 12.5(\(3\) F)
107 670.8 R(orw)-.15 E 1.627(arding and :include: features eliminate the requi\
rement that the system alias \214le be)-.1 F .074(writable by an)133.66 682.8 R
2.574(yu)-.15 G .073
(ser \(or that an update program be written, or that the system administration)
203.442 682.8 R(mak)133.66 694.8 Q 2.5(ea)-.1 G(ll changes\).)162.16 694.8 Q
(\(4\))107 711 Q F2(Sendmail)133.66 711 Q F1 .4
(supports message batching across netw)2.9 F .401
(orks when a message is being sent to mul-)-.1 F(tiple recipients.)133.66 723 Q
EP
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/F0 10/Times-Bold@0 SF(SENDMAIL \212 An Inter)72 60 Q(netw)-.15 E
(ork Mail Router)-.1 E(SMM:9-9)462.9 60 Q/F1 10/Times-Roman@0 SF 12.5(\(5\) A)
107 96 R .875(mail queue is pro)3.375 F .874(vided in)-.15 F/F2 10
/Times-Italic@0 SF(sendmail.)3.374 E F1 .874(Mail that cannot be deli)5.874 F
-.15(ve)-.25 G .874(red immediately b).15 F .874(ut can)-.2 F 1.063
(potentially be deli)133.66 108 R -.15(ve)-.25 G 1.064
(red later is stored in this queue for a later retry).15 F 6.064(.T)-.65 G
1.064(he queue also pro-)427.218 108 R .896(vides a b)133.66 120 R(uf)-.2 E
.896(fer ag)-.25 F .895
(ainst system crashes; after the message has been collected it may be reli-)
-.05 F(ably redeli)133.66 132 Q -.15(ve)-.25 G(red e).15 E -.15(ve)-.25 G 2.5
(ni).15 G 2.5(ft)224.22 132 S(he system crashes during the initial deli)232.83
132 Q -.15(ve)-.25 G(ry).15 E(.)-.65 E(\(6\))107 148.2 Q F2(Sendmail)133.66
148.2 Q F1 .197(uses the netw)2.696 F .197(orking support pro)-.1 F .197
(vided by 4.2BSD to pro)-.15 F .197(vide a direct interf)-.15 F .197(ace net-)
-.1 F -.1(wo)133.66 160.2 S .07(rks such as the ARP).1 F .07
(ANET and/or Ethernet using SMTP \(the Simple Mail T)-.92 F .07(ransfer Proto-)
-.35 F(col\) o)133.66 172.2 Q -.15(ve)-.15 G 2.5(raT).15 G(CP/IP connection.)
184.73 172.2 Q F0 2.5(4.2. MMDF)87 196.2 R F1 .957(MMDF [Crock)127 212.4 R .957
(er79] spans a wider problem set than)-.1 F F2(sendmail)3.458 E F1 5.958(.F)C
.958(or e)395.058 212.4 R .958(xample, the domain of)-.15 F .721
(MMDF includes a \231phone netw)102 224.4 R .721(ork\232 mailer)-.1 F 3.221(,w)
-.4 G(hereas)290.516 224.4 Q F2(sendmail)3.221 E F1 .721(calls on pree)3.221 F
.72(xisting mailers in most)-.15 F(cases.)102 236.4 Q .175(MMDF and)127 252.6 R
F2(sendmail)2.675 E F1 .175
(both support aliasing, customized mailers, message batching, automatic)2.675 F
(forw)102 264.6 Q .792(arding to g)-.1 F(ate)-.05 E -.1(wa)-.25 G .792
(ys, queueing, and retransmission.).1 F .792(MMDF supports tw)5.792 F .792
(o-stage timeout, which)-.1 F F2(sendmail)102 276.6 Q F1(does not support.)2.5
E(The con\214guration for MMDF is compiled into the code)127 294.8 Q/F3 7
/Times-Roman@0 SF(4)348.65 290.8 Q F1(.)352.15 294.8 Q .037
(Since MMDF does not consider backw)127 311 R .037
(ards compatibility as a design goal, the address parsing)-.1 F(is simpler b)
102 323 Q(ut much less \215e)-.2 E(xible.)-.15 E 1.159(It is some)127 341.2 R
1.159(what harder to inte)-.25 F 1.159(grate a ne)-.15 F 3.659(wc)-.25 G
(hannel)302.802 341.2 Q F3(5)329.462 337.2 Q F1 1.159(into MMDF)336.621 341.2 R
6.16(.I)-.8 G 3.66(np)397.59 341.2 S(articular)411.25 341.2 Q 3.66(,M)-.4 G
1.16(MDF must)459.22 341.2 R(kno)102 353.2 Q 3.225(wt)-.25 G .725(he location \
and format of host tables for all channels, and the channel must speak a speci\
al)129.975 353.2 R 2.525(protocol. This)102 365.2 R(allo)2.525 E .025
(ws MMDF to do additional v)-.25 F .025(eri\214cation \(such as v)-.15 F .025
(erifying host names\) at submis-)-.15 F(sion time.)102 377.2 Q 1.761
(MMDF strictly separates the submission and deli)127 393.4 R -.15(ve)-.25 G
1.761(ry phases.).15 F(Although)6.761 E F2(sendmail)4.261 E F1 1.76(has the)
4.261 F .784(concept of each of these stages, the)102 405.4 R 3.284(ya)-.15 G
.784(re inte)260.068 405.4 R .785(grated into one program, whereas in MMDF the)
-.15 F 3.285(ya)-.15 G(re)496.23 405.4 Q(split into tw)102 417.4 Q 2.5(op)-.1 G
(rograms.)162.19 417.4 Q F0 2.5(4.3. Message)87 441.4 R(Pr)2.5 E
(ocessing Module)-.18 E F1 .925
(The Message Processing Module \(MPM\) discussed by Postel [Postel79b] matches)
127 457.6 R F2(sendmail)3.425 E F1 1.364
(closely in terms of its basic architecture.)102 469.6 R(Ho)6.364 E(we)-.25 E
-.15(ve)-.25 G 2.164 -.4(r, l).15 H(ik).4 E 3.864(eM)-.1 G(MDF)347.526 469.6 Q
3.864(,t)-.8 G 1.365(he MPM includes the netw)377.54 469.6 R(ork)-.1 E(interf)
102 481.6 Q(ace softw)-.1 E(are as part of its domain.)-.1 E .408
(MPM also postulates a duple)127 497.8 R 2.907(xc)-.15 G .407
(hannel to the recei)256.937 497.8 R -.15(ve)-.25 G 1.207 -.4(r, a).15 H 2.907
(sd).4 G .407(oes MMDF)365.362 497.8 R 2.907(,t)-.8 G .407(hus allo)419.546
497.8 R .407(wing simpler)-.25 F .302
(handling of errors by the mailer than is possible in)102 509.8 R F2(sendmail)
2.802 E F1 5.302(.W)C .302(hen a message queued by)362.24 509.8 R F2(sendmail)
2.802 E F1 .23(is sent, an)102 521.8 R 2.73(ye)-.15 G .23
(rrors must be returned to the sender by the mailer itself.)154.2 521.8 R .229
(Both MPM and MMDF mail-)5.229 F .883(ers can return an immediate error respon\
se, and a single error processor can create an appropriate)102 533.8 R
(response.)102 545.8 Q 2.24
(MPM prefers passing the message as a structured object, with type-length-v)127
564 R 2.24(alue tuples)-.25 F F3(6)498 560 Q F1(.)501.5 564 Q .874(Such a con)
102 576 R -.15(ve)-.4 G .874(ntion requires a much higher de).15 F .875
(gree of cooperation between mailers than is required)-.15 F(by)102 588 Q F2
(sendmail)2.796 E F1 5.296(.M)C .296(PM also assumes a uni)167.592 588 R -.15
(ve)-.25 G .296(rsally agreed upon internet name space \(with each address).15
F(in the form of a net-host-user tuple\), which)102 600 Q F2(sendmail)2.5 E F1
(does not.)2.5 E .32 LW 76 642 72 642 DL 80 642 76 642 DL 84 642 80 642 DL 88
642 84 642 DL 92 642 88 642 DL 96 642 92 642 DL 100 642 96 642 DL 104 642 100
642 DL 108 642 104 642 DL 112 642 108 642 DL 116 642 112 642 DL 120 642 116 642
DL 124 642 120 642 DL 128 642 124 642 DL 132 642 128 642 DL 136 642 132 642 DL
140 642 136 642 DL 144 642 140 642 DL 148 642 144 642 DL 152 642 148 642 DL 156
642 152 642 DL 160 642 156 642 DL 164 642 160 642 DL 168 642 164 642 DL 172 642
168 642 DL 176 642 172 642 DL 180 642 176 642 DL 184 642 180 642 DL 188 642 184
642 DL 192 642 188 642 DL 196 642 192 642 DL 200 642 196 642 DL 204 642 200 642
DL 208 642 204 642 DL 212 642 208 642 DL 216 642 212 642 DL/F4 5/Times-Roman@0
SF(4)93.6 652.4 Q/F5 8/Times-Roman@0 SF .179
(Dynamic con\214guration tables are currently being considered for MMDF; allo)
3.2 J .18(wing the installer to select either compiled or dy-)-.2 F
(namic tables.)72 665.2 Q F4(5)93.6 675.6 Q F5(The MMDF equi)3.2 I -.2(va)-.2 G
(lent of a).2 E/F6 8/Times-Italic@0 SF(sendmail)2 E F5(\231mailer)2 E -.56
<2e9a>-.44 G F4(6)93.6 689.2 Q F5(This is similar to the NBS standard.)3.2 I EP
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/F0 10/Times-Bold@0 SF 187.28(SMM:9-10 SENDMAIL)72 60 R 2.5<8a41>2.5 G 2.5(nI)
383.99 60 S(nter)395.94 60 Q(netw)-.15 E(ork Mail Router)-.1 E 2.5(5. EV)72 96
R(ALU)-1.35 E -.95(AT)-.6 G(IONS AND FUTURE PLANS).95 E/F1 10/Times-Italic@0 SF
(Sendmail)112 112.2 Q/F2 10/Times-Roman@0 SF 1.851(is designed to w)4.351 F
1.851(ork in a nonhomogeneous en)-.1 F 4.352(vironment. Ev)-.4 F 1.852
(ery attempt is made to)-.15 F -.2(avo)87 124.2 S 1.037
(id imposing unnecessary constraints on the underlying mailers.).2 F 1.036
(This goal has dri)6.036 F -.15(ve)-.25 G 3.536(nm).15 G 1.036(uch of the)
461.938 124.2 R 2.723(design. One)87 136.2 R .223(of the major problems has be\
en the lack of a uniform address space, as postulated in [Pos-)2.723 F
(tel79a] and [Postel79b].)87 148.2 Q 2.647(An)112 164.4 S .147(onuniform addre\
ss space implies that a path will be speci\214ed in all addresses, either e)
126.867 164.4 R(xplicitly)-.15 E .472
(\(as part of the address\) or implicitly \(as with implied forw)87 176.4 R
.473(arding to g)-.1 F(ate)-.05 E -.1(wa)-.25 G 2.973(ys\). This).1 F .473
(restriction has the)2.973 F .493(unpleasant ef)87 188.4 R .493
(fect of making replying to messages e)-.25 F .493(xceedingly dif)-.15 F .493
(\214cult, since there is no one \231address\232)-.25 F(for an)87 200.4 Q 2.5
(yp)-.15 G(erson, b)122.95 200.4 Q(ut only a w)-.2 E
(ay to get there from where)-.1 E -.15(ve)-.25 G 2.5(ry).15 G(ou are.)324.7
200.4 Q(Interf)112 216.6 Q .448(acing to mail programs that were not initially\
 intended to be applied in an internet en)-.1 F(viron-)-.4 E(ment has been ama\
zingly successful, and has reduced the job to a manageable task.)87 228.6 Q F1
(Sendmail)112 244.8 Q F2 2.906(has kno)5.406 F 2.906(wledge of a fe)-.25 F
5.406(wd)-.25 G(if)271.126 244.8 Q 2.906(\214cult en)-.25 F 2.906(vironments b)
-.4 F 2.906(uilt in.)-.2 F 2.905(It generates ARP)7.906 F(ANET)-.92 E .648(FTP\
/SMTP compatible error messages \(prepended with three-digit numbers [Neigus73\
, Postel74, Pos-)87 256.8 R .771(tel82]\) as necessary)87 268.8 R 3.271(,o)-.65
G .771(ptionally generates UNIX-style \231From\232 lines on the front of messa\
ges for some)177.523 268.8 R 1.669(mailers, and kno)87 280.8 R 1.669(ws ho)-.25
F 4.169(wt)-.25 G 4.169(op)195.666 280.8 S 1.669(arse the same lines on input.)
209.835 280.8 R 1.67(Also, error handling has an option cus-)6.67 F
(tomized for BerkNet.)87 292.8 Q 1.482(The decision to a)112 309 R -.2(vo)-.2 G
1.482(id doing an).2 F 3.982(yt)-.15 G 1.481(ype of deli)254.222 309 R -.15(ve)
-.25 G 1.481(ry where possible \(e).15 F -.15(ve)-.25 G 1.481
(n, or perhaps especially).15 F(,)-.65 E .574(local deli)87 321 R -.15(ve)-.25
G .574(ry\) has turned out to be a good idea.).15 F(Ev)5.574 E .574
(en with local deli)-.15 F -.15(ve)-.25 G(ry).15 E 3.074(,t)-.65 G .575
(here are issues of the loca-)394.776 321 R .469(tion of the mailbox, the form\
at of the mailbox, the locking protocol used, etc., that are best decided by)87
333 R .038(other programs.)87 345 R .038(One surprisingly major anno)5.038 F
.038(yance in man)-.1 F 2.538(yi)-.15 G .038
(nternet mailers is that the location and for)333.684 345 R(-)-.2 E .138
(mat of local mail is b)87 357 R .138(uilt in.)-.2 F .137
(The feeling seems to be that local mail is so common that it should be ef)
5.137 F<8c2d>-.25 E 3.045(cient. This)87 3