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/F0 14/Times-Roman@0 SF(SENDMAIL \212 An Internetw)159.172 141 Q
(ork Mail Router)-.14 E/F1 10/Times-Roman@0 SF(Eric Allman*)260.92 165 Q/F2 10
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(y)-.3 E(Mammoth Pr)251.98 195 Q(oject)-.45 E F1(ABSTRA)262.085 227.4 Q(CT)-.4
E 1.41(Routing mail through a heterogenous internet presents man)112 243.6 R
3.91(yn)-.15 G 1.91 -.25(ew p)372.55 243.6 T 3.91(roblems. Among).25 F .297
(the w)112 255.6 R .297(orst of these is that of address mapping.)-.1 F
(Historically)5.297 E 2.797(,t)-.65 G .298(his has been handled on an)355.03
255.6 R F2(ad hoc)112 267.6 Q F1 2.5(basis. Ho)2.5 F(we)-.25 E -.15(ve)-.25 G
.8 -.4(r, t).15 H(his approach has become unmanageable as internets gro).4 E
-.65(w.)-.25 G .15(Sendmail acts a uni\214ed "post of)112 283.8 R .15
(\214ce" to which all mail can be submitted.)-.25 F .15(Address inter)5.15 F(-)
-.2 E .426(pretation is controlled by a production system, which can parse bot\
h domain-based ad-)112 295.8 R .423(dressing and old-style)112 307.8 R F2 .423
(ad hoc)2.923 F F1 2.923(addresses. The)2.923 F .422(production system is po)
2.922 F .422(werful enough to)-.25 F(re)112 319.8 Q 1.357(write addresses in t\
he message header to conform to the standards of a number of)-.25 F 1.15
(common tar)112 331.8 R 1.15(get netw)-.18 F 1.15
(orks, including old \(NCP/RFC733\) Arpanet, ne)-.1 F 3.65(w\()-.25 G
(TCP/RFC822\))405.65 331.8 Q 1.119(Arpanet, UUCP)112 343.8 R 3.619(,a)-1.11 G
1.119(nd Phonenet.)186.448 343.8 R 1.119(Sendmail also implements an SMTP serv)
6.119 F(er)-.15 E 3.619(,m)-.4 G(essage)437.9 343.8 Q(queueing, and aliasing.)
112 355.8 Q F2(Sendmail)97 400.2 Q F1 .501(implements a general internetw)3 F
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(eaturing aliasing and forw)369.847 400.2 R(arding,)-.1 E
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(ys, and \215e).1 E(xible con\214guration.)-.15 E .624(In a simple netw)97
428.4 R .624(ork, each node has an address, and resources can be identi\214ed \
with a host-resource)-.1 F .374(pair; in particular)72 440.4 R 2.874(,t)-.4 G
.374(he mail system can refer to users using a host-username pair)149.932 440.4
R 5.374(.H)-.55 G .375(ost names and numbers)409.276 440.4 R(ha)72 452.4 Q .3
-.15(ve t)-.2 H 2.5(ob).15 G 2.5(ea)108.31 452.4 S
(dministered by a central authority)119.69 452.4 Q 2.5(,b)-.65 G
(ut usernames can be assigned locally to each host.)263.82 452.4 Q .649
(In an internet, multiple netw)97 468.6 R .649(orks with dif)-.1 F .649
(ferent characterstics and managements must communicate.)-.25 F .389
(In particular)72 480.6 R 2.889(,t)-.4 G .389
(he syntax and semantics of resource identi\214cation change.)129.308 480.6 R
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(vially by)-.25 F F2 1.033(ad hoc)3.533 F F1 1.032(techniques, such as pro)
3.533 F 1.032(viding netw)-.15 F 1.032
(ork names that appear local to hosts on other)-.1 F(netw)72 504.6 Q 1.454
(orks, as with the Ethernet at Xerox P)-.1 F 3.955(ARC. Ho)-.92 F(we)-.25 E
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(xtremely comple)-.15 F 3.955(x. F)-.15 F(or)-.15 E -.15(ex)72 516.6 S .192
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e entered into the system tables, while others use end-to-end addressing.)72
528.6 R(Some)5.618 E(netw)72 540.6 Q .123(orks use a left-associati)-.1 F .423
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(ve s)-.25 H .123(yntax, causing ambiguity in mix).15 F(ed)-.15 E(addresses.)72
552.6 Q .678(Internet standards seek to eliminate these problems.)97 568.8 R
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(xpanding the address)-.15 F .65(pairs to address triples, consisting of {netw)
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(ork numbers must be uni)-.1 F -.15(ve)-.25 G -.2(r-).15 G 1.452
(sally agreed upon, and hosts can be assigned locally on each netw)72 592.8 R
3.952(ork. The)-.1 F(user)3.952 E(-le)-.2 E -.15(ve)-.25 G 3.952(lp).15 G 1.452
(resentation w)440.718 592.8 R(as)-.1 E 2.352(quickly e)72 604.8 R 2.352(xpand\
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erarchical)-.15 F .256(domain speci\214cation with a common static root.)72
616.8 R .257(The domain technique separates the issue of ph)5.257 F .257
(ysical v)-.05 F(er)-.15 E(-)-.2 E .807(sus logical addressing.)72 628.8 R -.15
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(xample, an address of the form \231eric@a.cc.berk)191.028 628.8 R(ele)-.1 E
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F F2 .493(ad hoc)2.993 F F1 -.1(wo)2.993 G .493(rld of netw).1 F .493
(orks that kno)-.1 F(w)-.25 E .855
(nothing of each other and the clean, tightly-coupled w)72 669 R .854
(orld of unique netw)-.1 F .854(ork numbers.)-.1 F .854(It can accept old)5.854
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(*A considerable part of this w)93.6 690.6 R .557(ork w)-.08 F .557
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(rsity of California at).12 F(Berk)72 700.2 Q(ele)-.08 E 2(ya)-.12 G
(nd at Britton Lee.)106.232 700.2 Q/F4 10/Times-Bold@0 SF
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383.99 60 S(nter)395.94 60 Q(netw)-.15 E(ork Mail Router)-.1 E/F1 10
/Times-Roman@0 SF .632(arbitrary address syntax)72 96 R .633(es, resolving amb\
iguities using heuristics speci\214ed by the system administrator)-.15 F 3.133
(,a)-.4 G(s)500.11 96 Q .348(well as domain-based addressing.)72 108 R .347
(It helps guide the con)5.347 F -.15(ve)-.4 G .347
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(rks. In).1 F(short,)3.394 E/F2 10/Times-Italic@0 SF(sendmail)3.394 E F1 .894
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(Section 1 discusses the design goals for)97 160.2 R F2(sendmail)2.653 E F1
5.153(.S)C .152(ection 2 gi)308.214 160.2 R -.15(ve)-.25 G 2.652(sa).15 G 2.652
(no)370.76 160.2 S -.15(ve)383.262 160.2 S(rvie).15 E 2.652(wo)-.25 G 2.652(ft)
422.724 160.2 S .152(he basic functions)431.486 160.2 R .644(of the system.)72
172.2 R .644(In section 3, details of usage are discussed.)5.644 F .644
(Section 4 compares)5.644 F F2(sendmail)3.144 E F1 .645(to other internet)3.144
F(mail routers, and an e)72 184.2 Q -.25(va)-.25 G(luation of).25 E F2
(sendmail)2.5 E F1(is gi)2.5 E -.15(ve)-.25 G 2.5(ni).15 G 2.5(ns)283.3 184.2 S
(ection 5, including future plans.)294.69 184.2 Q F0 2.5(1. DESIGN)72 208.2 R
(GO)2.5 E(ALS)-.4 E F1(Design goals for)112 224.4 Q F2(sendmail)2.5 E F1
(include:)2.5 E 12.5(\(1\) Compatibility)92 240.6 R 1.363(with the e)3.864 F
1.363(xisting mail programs, including Bell v)-.15 F 1.363
(ersion 6 mail, Bell v)-.15 F 1.363(ersion 7)-.15 F 1.202(mail [UNIX83], Berk)
118.66 252.6 R(ele)-.1 E(y)-.15 E F2(Mail)3.702 E F1 1.202
([Shoens79], BerkNet mail [Schmidt79], and hopefully UUCP)3.702 F(mail [No)
118.66 264.6 Q(witz78a, No)-.25 E 2.5(witz78b]. ARP)-.25 F(ANET mail [Crock)
-.92 E(er77a, Postel77] w)-.1 E(as also required.)-.1 E 12.5(\(2\) Reliability)
92 280.8 R 4.003(,i)-.65 G 4.003(nt)169.523 280.8 S 1.502
(he sense of guaranteeing that e)181.306 280.8 R -.15(ve)-.25 G 1.502
(ry message is correctly deli).15 F -.15(ve)-.25 G 1.502(red or at least).15 F
.368
(brought to the attention of a human for correct disposal; no message should e)
118.66 292.8 R -.15(ve)-.25 G 2.868(rb).15 G 2.868(ec)452.252 292.8 S
(ompletely)464 292.8 Q 2.541(lost. This)118.66 304.8 R .041(goal w)2.541 F .041
(as considered essential because of the emphasis on mail in our en)-.1 F 2.54
(vironment. It)-.4 F 1.754
(has turned out to be one of the hardest goals to satisfy)118.66 316.8 R 4.255
(,e)-.65 G 1.755(specially in the f)363.75 316.8 R 1.755(ace of the man)-.1 F
(y)-.15 E .978(anomalous message formats produced by v)118.66 328.8 R .977
(arious ARP)-.25 F .977(ANET sites.)-.92 F -.15(Fo)5.977 G 3.477(re).15 G .977
(xample, certain sites)420.116 328.8 R .069
(generate improperly formated addresses, occasionally causing error)118.66
340.8 R .069(-message loops.)-.2 F .069(Some hosts)5.069 F .063(use blanks in \
names, causing problems with UNIX mail programs that assume that an address is)
118.66 352.8 R .111(one w)118.66 364.8 R 2.611(ord. The)-.1 F .111
(semantics of some \214elds are interpreted slightly dif)2.611 F .112
(ferently by dif)-.25 F .112(ferent sites.)-.25 F(In)5.112 E(summary)118.66
376.8 Q 3.023(,t)-.65 G .523(he obscure features of the ARP)163.533 376.8 R
.523(ANET mail protocol really)-.92 F F2(ar)3.023 E(e)-.37 E F1 .522
(used and are dif)3.023 F(\214cult)-.25 E(to support, b)118.66 388.8 Q
(ut must be supported.)-.2 E 12.5(\(3\) Existing)92 405 R(softw)2.938 E .438
(are to do actual deli)-.1 F -.15(ve)-.25 G .439(ry should be used whene).15 F
-.15(ve)-.25 G 2.939(rp).15 G 2.939(ossible. This)387.654 405 R .439(goal deri)
2.939 F -.15(ve)-.25 G 2.939(sa).15 G(s)500.11 405 Q
(much from political and practical considerations as technical.)118.66 417 Q
12.5(\(4\) Easy)92 433.2 R -.15(ex)2.899 G .399(pansion to f).15 F .399
(airly comple)-.1 F 2.898(xe)-.15 G -.4(nv)261.064 433.2 S .398
(ironments, including multiple connections to a single net-).4 F -.1(wo)118.66
445.2 S .115
(rk type \(such as with multiple UUCP or Ether nets [Metcalfe76]\).).1 F .115
(This goal requires consid-)5.115 F .587(eration of the contents of an address\
 as well as its syntax in order to determine which g)118.66 457.2 R(ate)-.05 E
-.1(wa)-.25 G(y).1 E 1.018(to use.)118.66 469.2 R -.15(Fo)6.018 G 3.518(re).15
G 1.018(xample, the ARP)173.354 469.2 R 1.019
(ANET is bringing up the TCP protocol to replace the old NCP)-.92 F 4.791
(protocol. No)118.66 481.2 R 2.291(host at Berk)4.791 F(ele)-.1 E 4.791(yr)-.15
G 2.291(uns both TCP and NCP)256.235 481.2 R 4.791(,s)-1.11 G 4.79(oi)369.37
481.2 S 4.79(ti)381.94 481.2 S 4.79(sn)392.29 481.2 S 2.29
(ecessary to look at the)405.97 481.2 R(ARP)118.66 493.2 Q .016
(ANET host name to determine whether to route mail to an NCP g)-.92 F(ate)-.05
E -.1(wa)-.25 G 2.517(yo).1 G 2.517(raT)435.569 493.2 S .017(CP g)454.483 493.2
R(ate)-.05 E -.1(wa)-.25 G -.65(y.).1 G 12.5(\(5\) Con\214guration)92 509.4 R
.145(should not be compiled into the code.)2.645 F 2.645(As)5.145 G .145
(ingle compiled program should be able)346.905 509.4 R .91(to run as is at an)
118.66 521.4 R 3.41(ys)-.15 G .91
(ite \(barring such basic changes as the CPU type or the operating system\).)
200.63 521.4 R 2.61 -.8(We h)118.66 533.4 T -2.25 -.2(av e).8 H 1.009
(found this seemingly unimportant goal to be critical in real life.)3.71 F
1.009(Besides the simple)6.009 F .66(problems that occur when an)118.66 545.4 R
3.16(yp)-.15 G .66(rogram gets recompiled in a dif)249.84 545.4 R .66
(ferent en)-.25 F .66(vironment, man)-.4 F 3.16(ys)-.15 G(ites)490.11 545.4 Q
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150.78 557.4 Q(ything that the)-.15 E 2.5(yw)-.15 G(ill be recompiling an)
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573.6 Q F1 .184(must be able to let v)2.684 F .184
(arious groups maintain their o)-.25 F .184(wn mailing lists, and let indi)-.25
F(viduals)-.25 E(specify their o)118.66 585.6 Q(wn forw)-.25 E
(arding, without modifying the system alias \214le.)-.1 E 12.5(\(7\) Each)92
601.8 R .313(user should be able to specify which mailer to e)2.813 F -.15(xe)
-.15 G .313(cute to process mail being deli).15 F -.15(ve)-.25 G .314(red for)
.15 F 3.098(him. This)118.66 613.8 R .598(feature allo)3.098 F .598
(ws users who are using specialized mailers that use a dif)-.25 F .598
(ferent format to)-.25 F -.2(bu)118.66 625.8 S .25(ild their en).2 F .25
(vironment without changing the system, and f)-.4 F .25
(acilitates specialized functions \(such)-.1 F(as returning an \231I am on v)
118.66 637.8 Q(acation\232 message\).)-.25 E 12.5(\(8\) Netw)92 654 R 1.553
(ork traf)-.1 F 1.552(\214c should be minimized by batching addresses to a sin\
gle host where possible,)-.25 F(without assistance from the user)118.66 666 Q
(.)-.55 E .374(These goals moti)112 682.2 R -.25(va)-.25 G .374
(ted the architecture illustrated in \214gure 1.).25 F .375
(The user interacts with a mail gen-)5.375 F .491(erating and sending program.)
87 694.2 R .491(When the mail is created, the generator calls)5.491 F F2
(sendmail)2.99 E F1 2.99(,w)C .49(hich routes the)444.14 694.2 R .84
(message to the correct mailer\(s\).)87 706.2 R .841
(Since some of the senders may be netw)5.84 F .841(ork serv)-.1 F .841
(ers and some of the)-.15 F(mailers may be netw)87 718.2 Q(ork clients,)-.1 E
F2(sendmail)2.5 E F1(may be used as an internet mail g)2.5 E(ate)-.05 E -.1(wa)
-.25 G -.65(y.).1 G 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:9-3)462.9 60 Q .4 LW 77 108 72 108 DL 79 108 74 108
DL 84 108 79 108 DL 89 108 84 108 DL 94 108 89 108 DL 99 108 94 108 DL 104 108
99 108 DL 109 108 104 108 DL 114 108 109 108 DL 119 108 114 108 DL 124 108 119
108 DL 129 108 124 108 DL 134 108 129 108 DL 139 108 134 108 DL 144 108 139 108
DL 149 108 144 108 DL 154 108 149 108 DL 159 108 154 108 DL 164 108 159 108 DL
169 108 164 108 DL 174 108 169 108 DL 179 108 174 108 DL 184 108 179 108 DL 189
108 184 108 DL 194 108 189 108 DL 199 108 194 108 DL 204 108 199 108 DL 209 108
204 108 DL 214 108 209 108 DL 219 108 214 108 DL 224 108 219 108 DL 229 108 224
108 DL 234 108 229 108 DL 239 108 234 108 DL 244 108 239 108 DL 249 108 244 108
DL 254 108 249 108 DL 259 108 254 108 DL 264 108 259 108 DL 269 108 264 108 DL
274 108 269 108 DL 279 108 274 108 DL 284 108 279 108 DL 289 108 284 108 DL 294
108 289 108 DL 299 108 294 108 DL 304 108 299 108 DL 309 108 304 108 DL 314 108
309 108 DL 319 108 314 108 DL 324 108 319 108 DL 329 108 324 108 DL 334 108 329
108 DL 339 108 334 108 DL 344 108 339 108 DL 349 108 344 108 DL 354 108 349 108
DL 359 108 354 108 DL 364 108 359 108 DL 369 108 364 108 DL 374 108 369 108 DL
379 108 374 108 DL 384 108 379 108 DL 389 108 384 108 DL 394 108 389 108 DL 399
108 394 108 DL 404 108 399 108 DL 409 108 404 108 DL 414 108 409 108 DL 419 108
414 108 DL 424 108 419 108 DL 429 108 424 108 DL 434 108 429 108 DL 439 108 434
108 DL 444 108 439 108 DL 449 108 444 108 DL 454 108 449 108 DL 459 108 454 108
DL 464 108 459 108 DL 469 108 464 108 DL 474 108 469 108 DL 479 108 474 108 DL
484 108 479 108 DL 489 108 484 108 DL 494 108 489 108 DL 499 108 494 108 DL 504
108 499 108 DL/F1 10/Times-Roman@0 SF(sender1)164.45 155.6 Q 144 135.6 144
171.6 DL 216 135.6 144 135.6 DL 216 171.6 216 135.6 DL 144 171.6 216 171.6 DL
(sender2)272.45 155.6 Q 252 135.6 252 171.6 DL 324 135.6 252 135.6 DL 324 171.6
324 135.6 DL 252 171.6 324 171.6 DL(sender3)380.45 155.6 Q 360 135.6 360 171.6
DL 432 135.6 360 135.6 DL 432 171.6 432 135.6 DL 360 171.6 432 171.6 DL 288
207.6 288 171.6 DL 288 207.6 286.2 200.4 DL 288 207.6 289.8 200.4 DL(sendmail)
269.945 227.6 Q 216 207.6 216 243.6 DL 360 207.6 216 207.6 DL 360 243.6 360
207.6 DL 216 243.6 360 243.6 DL 288 279.6 288 243.6 DL 288 279.6 286.2 272.4 DL
288 279.6 289.8 272.4 DL(mailer1)164.725 299.6 Q 144 279.6 144 315.6 DL 216
279.6 144 279.6 DL 216 315.6 216 279.6 DL 144 315.6 216 315.6 DL(mailer2)
272.725 299.6 Q 252 279.6 252 315.6 DL 324 279.6 252 279.6 DL 324 315.6 324
279.6 DL 252 315.6 324 315.6 DL(mailer3)380.725 299.6 Q 360 279.6 360 315.6 DL
432 279.6 360 279.6 DL 432 315.6 432 279.6 DL 360 315.6 432 315.6 DL 252 207.6
180 171.6 DL 252 207.6 244.728 206.016 DL 252 207.6 246.384 202.776 DL 324
207.6 396 171.6 DL 324 207.6 329.616 202.776 DL 324 207.6 331.272 206.016 DL
180 279.6 252 243.6 DL 180 279.6 185.616 274.776 DL 180 279.6 187.272 278.016
DL 396 279.6 324 243.6 DL 396 279.6 388.728 278.016 DL 396 279.6 390.384
274.776 DL(Figure 1 \212 Sendmail System Structure.)208 346.8 Q 77 358.8 72
358.8 DL 79 358.8 74 358.8 DL 84 358.8 79 358.8 DL 89 358.8 84 358.8 DL 94
358.8 89 358.8 DL 99 358.8 94 358.8 DL 104 358.8 99 358.8 DL 109 358.8 104
358.8 DL 114 358.8 109 358.8 DL 119 358.8 114 358.8 DL 124 358.8 119 358.8 DL
129 358.8 124 358.8 DL 134 358.8 129 358.8 DL 139 358.8 134 358.8 DL 144 358.8
139 358.8 DL 149 358.8 144 358.8 DL 154 358.8 149 358.8 DL 159 358.8 154 358.8
DL 164 358.8 159 358.8 DL 169 358.8 164 358.8 DL 174 358.8 169 358.8 DL 179
358.8 174 358.8 DL 184 358.8 179 358.8 DL 189 358.8 184 358.8 DL 194 358.8 189
358.8 DL 199 358.8 194 358.8 DL 204 358.8 199 358.8 DL 209 358.8 204 358.8 DL
214 358.8 209 358.8 DL 219 358.8 214 358.8 DL 224 358.8 219 358.8 DL 229 358.8
224 358.8 DL 234 358.8 229 358.8 DL 239 358.8 234 358.8 DL 244 358.8 239 358.8
DL 249 358.8 244 358.8 DL 254 358.8 249 358.8 DL 259 358.8 254 358.8 DL 264
358.8 259 358.8 DL 269 358.8 264 358.8 DL 274 358.8 269 358.8 DL 279 358.8 274
358.8 DL 284 358.8 279 358.8 DL 289 358.8 284 358.8 DL 294 358.8 289 358.8 DL
299 358.8 294 358.8 DL 304 358.8 299 358.8 DL 309 358.8 304 358.8 DL 314 358.8
309 358.8 DL 319 358.8 314 358.8 DL 324 358.8 319 358.8 DL 329 358.8 324 358.8
DL 334 358.8 329 358.8 DL 339 358.8 334 358.8 DL 344 358.8 339 358.8 DL 349
358.8 344 358.8 DL 354 358.8 349 358.8 DL 359 358.8 354 358.8 DL 364 358.8 359
358.8 DL 369 358.8 364 358.8 DL 374 358.8 369 358.8 DL 379 358.8 374 358.8 DL
384 358.8 379 358.8 DL 389 358.8 384 358.8 DL 394 358.8 389 358.8 DL 399 358.8
394 358.8 DL 404 358.8 399 358.8 DL 409 358.8 404 358.8 DL 414 358.8 409 358.8
DL 419 358.8 414 358.8 DL 424 358.8 419 358.8 DL 429 358.8 424 358.8 DL 434
358.8 429 358.8 DL 439 358.8 434 358.8 DL 444 358.8 439 358.8 DL 449 358.8 444
358.8 DL 454 358.8 449 358.8 DL 459 358.8 454 358.8 DL 464 358.8 459 358.8 DL
469 358.8 464 358.8 DL 474 358.8 469 358.8 DL 479 358.8 474 358.8 DL 484 358.8
479 358.8 DL 489 358.8 484 358.8 DL 494 358.8 489 358.8 DL 499 358.8 494 358.8
DL 504 358.8 499 358.8 DL F0 2.5(2. O)72 394.8 R(VER)-.5 E(VIEW)-.55 E 2.5
(2.1. System)87 418.8 R(Or)2.5 E(ganization)-.1 E/F2 10/Times-Italic@0 SF
(Sendmail)127 435 Q F1 .874(neither interf)3.374 F .874
(aces with the user nor does actual mail deli)-.1 F -.15(ve)-.25 G(ry).15 E
5.873(.R)-.65 G(ather)431.241 435 Q 3.373(,i)-.4 G 3.373(tc)459.484 435 S .873
(ollects a)470.077 435 R .619(message generated by a user interf)102 447 R .619
(ace program \(UIP\) such as Berk)-.1 F(ele)-.1 E(y)-.15 E F2(Mail)3.12 E F1
3.12(,M)C 3.12(S[)427.6 447 S(Crock)439.61 447 Q .62(er77b], or)-.1 F 1.428
(MH [Borden79], edits the message as required by the destination netw)102 459 R
1.427(ork, and calls appropriate)-.1 F .28(mailers to do mail deli)102 473 R
-.15(ve)-.25 G .281(ry or queueing for netw).15 F .281(ork transmission)-.1 F
/F3 7/Times-Roman@0 SF(1)364.275 469 Q F1 5.281(.T)367.775 473 S .281
(his discipline allo)381.666 473 R .281(ws the inser)-.25 F(-)-.2 E 1.354
(tion of ne)102 485 R 3.854(wm)-.25 G 1.354(ailers at minimum cost.)161.642 485
R 1.354(In this sense)6.354 F F2(sendmail)3.853 E F1 1.353
(resembles the Message Processing)3.853 F(Module \(MPM\) of [Postel79b].)102
497 Q F0 2.5(2.2. Interfaces)87 521 R(to the Outside W)2.5 E(orld)-.75 E F1
.041(There are three w)127 537.2 R(ays)-.1 E F2(sendmail)2.541 E F1 .041
(can communicate with the outside w)2.541 F .042(orld, both in recei)-.1 F .042
(ving and)-.25 F 1.195(in sending mail.)102 549.2 R 1.194
(These are using the con)6.194 F -.15(ve)-.4 G 1.194(ntional UNIX ar).15 F
1.194(gument v)-.18 F 1.194(ector/return status, speaking)-.15 F(SMTP o)102
561.2 Q -.15(ve)-.15 G 2.5(rap).15 G(air of UNIX pipes, and speaking SMTP o)
162.53 561.2 Q -.15(ve)-.15 G 2.5(ra).15 G 2.5(ni)348.03 561.2 S
(nterprocess\(or\) channel.)358.31 561.2 Q F0 2.5(2.2.1. Ar)102 585.2 R
(gument v)-.1 E(ector/exit status)-.1 E F1 .52(This technique is the standard \
UNIX method for communicating with the process.)142 601.4 R 3.02(Al)5.52 G(ist)
494.55 601.4 Q .442(of recipients is sent in the ar)117 613.4 R .441(gument v)
-.18 F(ector)-.15 E 2.941(,a)-.4 G .441
(nd the message body is sent on the standard input.)299.491 613.4 R(An)117
625.4 Q .351(ything that the mailer prints is simply collected and sent back t\
o the sender if there were an)-.15 F(y)-.15 E 2.621(problems. The)117 637.4 R
-.15(ex)2.621 G .121(it status from the mailer is collected after the message \
is sent, and a diagnostic).15 F(is printed if appropriate.)117 649.4 Q .32 LW
76 678.8 72 678.8 DL 80 678.8 76 678.8 DL 84 678.8 80 678.8 DL 88 678.8 84
678.8 DL 92 678.8 88 678.8 DL 96 678.8 92 678.8 DL 100 678.8 96 678.8 DL 104
678.8 100 678.8 DL 108 678.8 104 678.8 DL 112 678.8 108 678.8 DL 116 678.8 112
678.8 DL 120 678.8 116 678.8 DL 124 678.8 120 678.8 DL 128 678.8 124 678.8 DL
132 678.8 128 678.8 DL 136 678.8 132 678.8 DL 140 678.8 136 678.8 DL 144 678.8
140 678.8 DL 148 678.8 144 678.8 DL 152 678.8 148 678.8 DL 156 678.8 152 678.8
DL 160 678.8 156 678.8 DL 164 678.8 160 678.8 DL 168 678.8 164 678.8 DL 172
678.8 168 678.8 DL 176 678.8 172 678.8 DL 180 678.8 176 678.8 DL 184 678.8 180
678.8 DL 188 678.8 184 678.8 DL 192 678.8 188 678.8 DL 196 678.8 192 678.8 DL
200 678.8 196 678.8 DL 204 678.8 200 678.8 DL 208 678.8 204 678.8 DL 212 678.8
208 678.8 DL 216 678.8 212 678.8 DL/F4 5/Times-Roman@0 SF(1)93.6 689.2 Q/F5 8
/Times-Roman@0 SF -.12(ex)3.2 K(cept when mailing to a \214le, when).12 E/F6 8
/Times-Italic@0 SF(sendmail)2 E F5(does the deli)2 E -.12(ve)-.2 G(ry directly)
.12 E(.)-.52 E EP
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/F0 10/Times-Bold@0 SF 192.28(SMM:9-4 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(2.2.2. SMTP)
102 96 R -.1(ove)2.5 G 2.5(rp).1 G(ipes)186.52 96 Q/F1 10/Times-Roman@0 SF .774
(The SMTP protocol [Postel82] can be used to run an interacti)142 112.2 R 1.074
-.15(ve l)-.25 H .774(ock-step interf).15 F .774(ace with)-.1 F .507
(the mailer)117 124.2 R 5.507(.A)-.55 G .506(subprocess is still created, b)
175.461 124.2 R .506(ut no recipient addresses are passed to the mailer via)-.2
F .075(the ar)117 136.2 R .075(gument list.)-.18 F .075(Instead, the)5.075 F
2.575(ya)-.15 G .075
(re passed one at a time in commands sent to the processes stan-)249.805 136.2
R .19(dard input.)117 148.2 R(An)5.19 E .19(ything appearing on the standard o\
utput must be a reply code in a special format.)-.15 F F0 2.5(2.2.3. SMTP)102
172.2 R -.1(ove)2.5 G 2.5(ra).1 G 2.5(nI)185.96 172.2 S(PC connection)197.91
172.2 Q F1 .366(This technique is similar to the pre)142 188.4 R .366
(vious technique, e)-.25 F .366(xcept that it uses a 4.2bsd IPC chan-)-.15 F
.953(nel [UNIX83].)117 200.4 R .953(This method is e)5.953 F .953
(xceptionally \215e)-.15 F .952
(xible in that the mailer need not reside on the)-.15 F(same machine.)117 212.4
Q(It is normally used to connect to a sendmail process on another machine.)5 E
F0 2.5(2.3. Operational)87 236.4 R(Description)2.5 E F1 .228(When a sender w)
127 252.6 R .228(ants to send a message, it issues a request to)-.1 F/F2 10
/Times-Italic@0 SF(sendmail)2.729 E F1 .229(using one of the three)2.729 F
1.028(methods described abo)102 264.6 R -.15(ve)-.15 G(.).15 E F2(Sendmail)
6.028 E F1 1.028(operates in tw)3.528 F 3.528(od)-.1 G 1.028(istinct phases.)
325.706 264.6 R 1.028(In the \214rst phase, it collects)6.028 F .612
(and stores the message.)102 276.6 R .612(In the second phase, message deli)
5.612 F -.15(ve)-.25 G .612(ry occurs.).15 F .612(If there were errors during)
5.612 F 1.59(processing during the second phase,)102 288.6 R F2(sendmail)4.09 E
F1 1.59(creates and returns a ne)4.09 F 4.09(wm)-.25 G 1.59
(essage describing the)415.84 288.6 R
(error and/or returns an status code telling what went wrong.)102 300.6 Q F0
2.5(2.3.1. Ar)102 324.6 R(gument pr)-.1 E(ocessing and addr)-.18 E(ess parsing)
-.18 E F1(If)142 340.8 Q F2(sendmail)3.321 E F1 .821
(is called using one of the tw)3.321 F 3.322(os)-.1 G .822
(ubprocess techniques, the ar)320.66 340.8 R .822(guments are \214rst)-.18 F
.797(scanned and option speci\214cations are processed.)117 352.8 R .796
(Recipient addresses are then collected, either)5.796 F .717(from the command \
line or from the SMTP RCPT command, and a list of recipients is created.)117
364.8 R .347(Aliases are e)117 376.8 R .347
(xpanded at this step, including mailing lists.)-.15 F .347(As much v)5.347 F
.346(alidation as possible of the)-.25 F 1.001
(addresses is done at this step: syntax is check)117 388.8 R 1.002
(ed, and local addresses are v)-.1 F 1.002(eri\214ed, b)-.15 F 1.002
(ut detailed)-.2 F .709
(checking of host names and addresses is deferred until deli)117 400.8 R -.15
(ve)-.25 G(ry).15 E 5.708(.F)-.65 G(orw)388.946 400.8 Q .708
(arding is also performed)-.1 F(as the local addresses are v)117 412.8 Q
(eri\214ed.)-.15 E F2(Sendmail)142 429 Q F1 .307
(appends each address to the recipient list after parsing.)2.807 F .307
(When a name is aliased)5.307 F .322(or forw)117 441 R .322(arded, the old nam\
e is retained in the list, and a \215ag is set that tells the deli)-.1 F -.15
(ve)-.25 G .322(ry phase to).15 F .479(ignore this recipient.)117 453 R .479
(This list is k)5.479 F .479(ept free from duplicates, pre)-.1 F -.15(ve)-.25 G
.48(nting alias loops and duplicate).15 F(messages deli)117 465 Q -.15(ve)-.25
G(rd to the same recipient, as might occur if a person is in tw).15 E 2.5(og)
-.1 G(roups.)428.12 465 Q F0 2.5(2.3.2. Message)102 489 R(collection)2.5 E F2
(Sendmail)142 505.2 Q F1 .454(then collects the message.)2.954 F .454
(The message should ha)5.454 F .754 -.15(ve a h)-.2 H .453(eader at the be).15
F(ginning.)-.15 E .778(No formatting requirements are imposed on the message e)
117 517.2 R .778(xcept that the)-.15 F 3.278(ym)-.15 G .778(ust be lines of te)
427.708 517.2 R(xt)-.15 E .78(\(i.e., binary data is not allo)117 529.2 R 3.28
(wed\). The)-.25 F .779(header is parsed and stored in memory)3.28 F 3.279(,a)
-.65 G .779(nd the body of)443.613 529.2 R(the message is sa)117 541.2 Q -.15
(ve)-.2 G 2.5(di).15 G 2.5(nat)204.97 541.2 S(emporary \214le.)222.19 541.2 Q
3.227 -.8(To s)142 557.4 T 1.627(implify the program interf).8 F 1.628
(ace, the message is collected e)-.1 F -.15(ve)-.25 G 4.128(ni).15 G 4.128(fn)
420.536 557.4 S 4.128(oa)432.994 557.4 S 1.628(ddresses were)446.562 557.4 R
-.25(va)117 569.4 S 2.5(lid. The).25 F(message will be returned with an error)
2.5 E(.)-.55 E F0 2.5(2.3.3. Message)102 593.4 R(deli)2.5 E -.1(ve)-.1 G(ry).1
E F1 -.15(Fo)142 609.6 S 2.618(re).15 G .117
(ach unique mailer and host in the recipient list,)162.798 609.6 R F2(sendmail)
2.617 E F1 .117(calls the appropriate mailer)2.617 F(.)-.55 E .619
(Each mailer in)117 621.6 R -.2(vo)-.4 G .619(cation sends to all users recei)
.2 F .619(ving the message on one host.)-.25 F .62(Mailers that only)5.62 F
(accept one recipient at a time are handled properly)117 633.6 Q(.)-.65 E .47
(The message is sent to the mailer using one of the same three interf)142 649.8
R .47(aces used to submit a)-.1 F 1.465(message to sendmail.)117 661.8 R 1.465
(Each cop)6.465 F 3.965(yo)-.1 G 3.965(ft)263.925 661.8 S 1.465
(he message is prepended by a customized header)274 661.8 R 6.465(.T)-.55 G(he)
494.56 661.8 Q 1.455(mailer status code is caught and check)117 673.8 R 1.455
(ed, and a suitable error message gi)-.1 F -.15(ve)-.25 G 3.955(na).15 G 3.955
(sa)448.115 673.8 S(ppropriate.)460.4 673.8 Q .589(The e)117 685.8 R .589(xit \
code must conform to a system standard or a generic message \(\231Service una)
-.15 F -.25(va)-.2 G(ilable\232\)).25 E(is gi)117 697.8 Q -.15(ve)-.25 G(n.).15
E 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:9-5)462.9 60 Q 2.5(2.3.4. Queueing)102 96 R -.25(fo)
2.5 G 2.5(rr).25 G(etransmission)192.4 96 Q/F1 10/Times-Roman@0 SF .209(If the\
 mailer returned an status that indicated that it might be able to handle the \
mail later)142 112.2 R(,)-.4 E/F2 10/Times-Italic@0 SF(sendmail)117 124.2 Q F1
(will queue the mail and try ag)2.5 E(ain later)-.05 E(.)-.55 E F0 2.5
(2.3.5. Retur)102 148.2 R 2.5(nt)-.15 G 2.5(os)165.73 148.2 S(ender)177.12
148.2 Q F1 .588(If errors occur during processing,)142 164.4 R F2(sendmail)
3.088 E F1 .589(returns the message to the sender for retrans-)3.088 F 3.133
(mission. The)117 176.4 R .632(letter can be mailed back or written in the \
\214le \231dead.letter\232 in the sender')3.133 F 3.132(sh)-.55 G(ome)486.78
176.4 Q(directory)117 190.4 Q/F3 7/Times-Roman@0 SF(2)153.1 186.4 Q F1(.)156.6
190.4 Q F0 2.5(2.4. Message)87 214.4 R(Header Editing)2.5 E F1 1.756
(Certain editing of the message header occurs automatically)127 230.6 R 6.756
(.H)-.65 G 1.756(eader lines can be inserted)391.456 230.6 R .41
(under control of the con\214guration \214le.)102 242.6 R .41
(Some lines can be mer)5.41 F .41(ged; for e)-.18 F .41
(xample, a \231From:\232 line and)-.15 F 2.5<6199>102 254.6 S
(Full-name:\232 line can be mer)113.38 254.6 Q
(ged under certain circumstances.)-.18 E F0 2.5(2.5. Con\214guration)87 278.6 R
(File)2.5 E F1 .798(Almost all con\214guration information is read at runtime \
from an ASCII \214le, encoding macro)127 294.8 R .679
(de\214nitions \(de\214ning the v)102 306.8 R .678
(alue of macros used internally\), header declarations \(telling sendmail the)
-.25 F 1.009(format of header lines that it will process specially)102 318.8 R
3.509(,i)-.65 G 1.009(.e., lines that it will add or reformat\), mailer)320.398
318.8 R .478(de\214nitions \(gi)102 330.8 R .478(ving information such as the \
location and characteristics of each mailer\), and address)-.25 F(re)102 342.8
Q .428(writing rules \(a limited production system to re)-.25 F .429
(write addresses which is used to parse and re)-.25 F(write)-.25 E
(the addresses\).)102 354.8 Q 2.828 -.8(To i)127 371 T(mpro).8 E 1.528 -.15
(ve p)-.15 H 1.228(erformance when reading the con\214guration \214le, a memor\
y image can be pro-).15 F 2.5(vided. This)102 383 R(pro)2.5 E
(vides a \231compiled\232 form of the con\214guration \214le.)-.15 E F0 2.5
(3. USA)72 407 R(GE AND IMPLEMENT)-.55 E -.95(AT)-.9 G(ION).95 E 2.5(3.1. Ar)87
431 R(guments)-.1 E F1(Ar)127 447.2 Q .376
(guments may be \215ags and addresses.)-.18 F .377(Flags set v)5.377 F .377
(arious processing options.)-.25 F -.15(Fo)5.377 G(llo).15 E .377(wing \215ag)
-.25 F(ar)102 459.2 Q .281(guments, address ar)-.18 F .281(guments may be gi)
-.18 F -.15(ve)-.25 G .281(n, unless we are running in SMTP mode.).15 F .28
(Addresses fol-)5.28 F(lo)102 471.2 Q 2.5(wt)-.25 G(he syntax in RFC822 [Crock)
122.03 471.2 Q(er82] for ARP)-.1 E(ANET address formats.)-.92 E
(In brief, the format is:)5 E 12.5(\(1\) An)107 487.4 R
(ything in parentheses is thro)-.15 E(wn a)-.25 E -.1(wa)-.15 G 2.5(y\().1 G
(as a comment\).)299.65 487.4 Q 12.5(\(2\) An)107 503.6 R .051
(ything in angle brack)-.15 F .051(ets \(\231<)-.1 F .051
(>\232\) is preferred o)1.666 F -.15(ve)-.15 G 2.551(ra).15 G -.15(ny)348.064
503.6 S .051(thing else.).15 F .051(This rule implements the)5.051 F(ARP)133.66
515.6 Q(ANET standard that addresses of the form)-.92 E
(user name <machine-address>)173.66 531.8 Q(will send to the electronic \231ma\
chine-address\232 rather than the human \231user name.)133.66 548 Q<9a>-.7 E
12.5(\(3\) Double)107 564.2 R 2.246(quotes \()4.746 F -2.754 2.5("\) q)2.5 H
2.246(uote phrases; backslashes quote characters.)224.188 564.2 R 2.246
(Backslashes are more)7.246 F(po)133.66 576.2 Q .654(werful in that the)-.25 F
3.154(yw)-.15 G .655(ill cause otherwise equi)229.196 576.2 R -.25(va)-.25 G
.655(lent phrases to compare dif).25 F .655(ferently \212 for)-.25 F -.15(ex)
133.66 588.2 S(ample,).15 E F2(user)2.5 E F1(and)2.5 E F2("user")2.5 E F1
(are equi)2.5 E -.25(va)-.25 G(lent, b).25 E(ut)-.2 E F2(\\user)2.5 E F1
(is dif)2.5 E(ferent from either of them.)-.25 E -.15(Pa)127 604.4 S 1.12
(rentheses, angle brack).15 F 1.12
(ets, and double quotes must be properly balanced and nested.)-.1 F(The)6.12 E
(re)102 618.4 Q(writing rules control remaining parsing)-.25 E F3(3)266.17
614.4 Q F1(.)269.67 618.4 Q .32 LW 76 646 72 646 DL 80 646 76 646 DL 84 646 80
646 DL 88 646 84 646 DL 92 646 88 646 DL 96 646 92 646 DL 100 646 96 646 DL 104
646 100 646 DL 108 646 104 646 DL 112 646 108 646 DL 116 646 112 646 DL 120 646
116 646 DL 124 646 120 646 DL 128 646 124 646 DL 132 646 128 646 DL 136 646 132
646 DL 140 646 136 646 DL 144 646 140 646 DL 148 646 144 646 DL 152 646 148 646
DL 156 646 152 646 DL 160 646 156 646 DL 164 646 160 646 DL 168 646 164 646 DL
172 646 168 646 DL 176 646 172 646 DL 180 646 176 646 DL 184 646 180 646 DL 188
646 184 646 DL 192 646 188 646 DL 196 646 192 646 DL 200 646 196 646 DL 204 646
200 646 DL 208 646 204 646 DL 212 646 208 646 DL 216 646 212 646 DL/F4 5
/Times-Roman@0 SF(2)93.6 656.4 Q/F5 8/Times-Roman@0 SF(Ob)3.2 I(viously)-.12 E
2.226(,i)-.52 G 2.226(ft)135.246 659.6 S .226(he site gi)142.36 659.6 R .226(v\
ing the error is not the originating site, the only reasonable option is to ma\
il back to the sender)-.2 F 4.227(.A)-.44 G(lso,)492.664 659.6 Q .191
(there are man)72 669.2 R 2.191(ym)-.12 G .19(ore error disposition options, b)
128.213 669.2 R .19(ut the)-.16 F 2.19(yo)-.12 G .19(nly ef)255.514 669.2 R .19
(fect the error message \212 the \231return to sender\232 function is al)-.2 F
-.08(wa)-.08 G .19(ys han-).08 F(dled in one of these tw)72 678.8 Q 2(ow)-.08 G
(ays.)156.272 678.8 Q F4(3)93.6 689.2 Q F5
(Disclaimer: Some special processing is done after re)3.2 I
(writing local names; see belo)-.2 E -.52(w.)-.2 G EP
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/F0 10/Times-Bold@0 SF 192.28(SMM:9-6 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(3.2. Mail)87
96 R(to Files and Pr)2.5 E(ograms)-.18 E/F1 10/Times-Roman@0 SF .609
(Files and programs are le)127 112.2 R .609(gitimate message recipients.)-.15 F
.609(Files pro)5.609 F .609(vide archi)-.15 F -.25(va)-.25 G 3.109(ls).25 G .61
(torage of mes-)445.02 112.2 R .124
(sages, useful for project administration and history)102 124.2 R 5.124(.P)-.65
G .124(rograms are useful as recipients in a v)318.308 124.2 R .124(ariety of)
-.25 F .69(situations, for e)102 136.2 R .691(xample, to maintain a public rep\
ository of systems messages \(such as the Berk)-.15 F(ele)-.1 E(y)-.15 E/F2 10
/Times-Italic@0 SF(msgs)102 148.2 Q F1(program, or the MARS system [Sattle)2.5
E(y78]\).)-.15 E(An)127 164.4 Q 3.188(ya)-.15 G .688(ddress passing through th\
e initial parsing algorithm as a local address \(i.e, not appear)151.698 164.4
R(-)-.2 E .276(ing to be a v)102 176.4 R .276
(alid address for another mailer\) is scanned for tw)-.25 F 2.776(os)-.1 G .277
(pecial cases.)362.128 176.4 R .277(If pre\214x)5.277 F .277(ed by a v)-.15 F
(erti-)-.15 E .18(cal bar \(\231)102 188.4 R .833<7c9a>.833 G 2.68(\)t)-.833 G
.179(he rest of the address is processed as a shell command.)156.456 188.4 R
.179(If the user name be)5.179 F .179(gins with a)-.15 F(slash mark \(\231/)102
200.4 Q(\232\) the name is used as a \214le name, instead of a login name.).833
E .241(Files that ha)127 216.6 R .541 -.15(ve s)-.2 H .241
(etuid or setgid bits set b).15 F .241(ut no e)-.2 F -.15(xe)-.15 G .241
(cute bits set ha).15 F .541 -.15(ve t)-.2 H .241(hose bits honored if).15 F F2
(send-)2.742 E(mail)102 228.6 Q F1(is running as root.)2.5 E F0 2.5
(3.3. Aliasing,)87 252.6 R -.25(Fo)2.5 G(rwarding, Inclusion).25 E F2(Sendmail)
127 268.8 Q F1 1.075(reroutes mail three w)3.575 F 3.575(ays. Aliasing)-.1 F
1.074(applies system wide.)3.575 F -.15(Fo)6.074 G(rw).15 E 1.074(arding allo)
-.1 F 1.074(ws each)-.25 F .233
(user to reroute incoming mail destined for that account.)102 280.8 R .233
(Inclusion directs)5.233 F F2(sendmail)2.733 E F1 .233(to read a \214le for)
2.733 F 2.5(al)102 292.8 S
(ist of addresses, and is normally used in conjunction with aliasing.)111.72
292.8 Q F0 2.5(3.3.1. Aliasing)102 316.8 R F1 1.554
(Aliasing maps names to address lists using a system-wide \214le.)142 333 R
1.553(This \214le is inde)6.553 F -.15(xe)-.15 G 4.053(dt).15 G(o)499 333 Q 1.1
(speed access.)117 345 R 1.101(Only names that parse as local are allo)6.1 F
1.101(wed as aliases; this guarantees a unique)-.25 F -.1(ke)117 357 S 2.5(y\()
-.05 G(since there are no nicknames for the local host\).)137.02 357 Q F0 2.5
(3.3.2. F)102 381 R(orwarding)-.25 E F1 .651
(After aliasing, recipients that are local and v)142 397.2 R .651
(alid are check)-.25 F .65(ed for the e)-.1 F .65(xistence of a \231.for)-.15 F
(-)-.2 E -.1(wa)117 409.2 S .493(rd\232 \214le in their home directory).1 F
5.493(.I)-.65 G 2.994(fi)264.178 409.2 S 2.994(te)273.282 409.2 S .494
(xists, the message is)283.346 409.2 R F2(not)2.994 E F1 .494
(sent to that user)2.994 F 2.994(,b)-.4 G .494(ut rather to)459.132 409.2 R .37
(the list of users in that \214le.)117 421.2 R .37
(Often this list will contain only one address, and the feature will be)5.37 F
(used for netw)117 433.2 Q(ork mail forw)-.1 E(arding.)-.1 E -.15(Fo)142 449.4
S(rw).15 E 1.151(arding also permits a user to specify a pri)-.1 F -.25(va)-.25
G 1.152(te incoming mailer).25 F 6.152(.F)-.55 G 1.152(or e)437.346 449.4 R
1.152(xample, for)-.15 F(-)-.2 E -.1(wa)117 461.4 S(rding to:).1 E -2.5 .833
("| /)157 477.6 T(usr/local/ne)-.833 E(wmail myname")-.25 E(will use a dif)117
493.8 Q(ferent incoming mailer)-.25 E(.)-.55 E F0 2.5(3.3.3. Inclusion)102
517.8 R F1(Inclusion is speci\214ed in RFC 733 [Crock)142 534 Q(er77a] syntax:)
-.1 E(:Include: pathname)157 550.2 Q .391
(An address of this form reads the \214le speci\214ed by)117 566.4 R F2
(pathname)2.891 E F1 .391(and sends to all users listed in that)2.891 F
(\214le.)117 578.4 Q .644(The intent is)142 594.6 R F2(not)3.144 E F1 .644
(to support direct use of this feature, b)3.144 F .644
(ut rather to use this as a subset of)-.2 F 2.5(aliasing. F)117 606.6 R(or e)
-.15 E(xample, an alias of the form:)-.15 E
(project: :include:/usr/project/userlist)157 622.8 Q 1.93(is a method of letti\
ng a project maintain a mailing list without interaction with the system)117
639 R(administration, e)117 651 Q -.15(ve)-.25 G 2.5(ni).15 G 2.5(ft)203.54 651
S(he alias \214le is protected.)212.15 651 Q 2.024(It is not necessary to reb)
142 667.2 R 2.024(uild the inde)-.2 F 4.524(xo)-.15 G 4.524(nt)317.822 667.2 S
2.025(he alias database when a :include: list is)330.126 667.2 R(changed.)117
679.2 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:9-7)462.9 60 Q 2.5(3.4. Message)87 96 R(Collection)
2.5 E/F1 10/Times-Roman@0 SF .857
(Once all recipient addresses are parsed and v)127 112.2 R .857
(eri\214ed, the message is collected.)-.15 F .856(The message)5.857 F
(comes in tw)102 124.2 Q 2.5(op)-.1 G
(arts: a message header and a message body)162.73 124.2 Q 2.5(,s)-.65 G
(eparated by a blank line.)343.42 124.2 Q
(The header is formatted as a series of lines of the form)127 140.4 Q
(\214eld-name: \214eld-v)178 156.6 Q(alue)-.25 E(Field-v)102 172.8 Q 1.366
(alue can be split across lines by starting the follo)-.25 F 1.366
(wing lines with a space or a tab)-.25 F 6.366(.S)-.4 G(ome)486.78 172.8 Q .211
(header \214elds ha)102 184.8 R .511 -.15(ve s)-.2 H .211
(pecial internal meaning, and ha).15 F .511 -.15(ve a)-.2 H .211
(ppropriate special processing.).15 F .21(Other headers)5.21 F
(are simply passed through.)102 196.8 Q
(Some header \214elds may be added automatically)5 E 2.5(,s)-.65 G
(uch as time stamps.)413.53 196.8 Q .86(The body is a series of te)127 213 R
.861(xt lines.)-.15 F .861(It is completely uninterpreted and untouched, e)
5.861 F .861(xcept that)-.15 F 1.43(lines be)102 225 R 1.43
(ginning with a dot ha)-.15 F 1.729 -.15(ve t)-.2 H 1.429
(he dot doubled when transmitted o).15 F -.15(ve)-.15 G 3.929(ra).15 G 3.929
(nS)407.213 225 S 1.429(MTP channel.)421.702 225 R(This)6.429 E -.15(ex)102 237
S(tra dot is stripped by the recei).15 E -.15(ve)-.25 G -.55(r.).15 G F0 2.5
(3.5. Message)87 261 R(Deli)2.5 E -.1(ve)-.1 G(ry).1 E F1 .028
(The send queue is ordered by recei)127 277.2 R .029
(ving host before transmission to implement message batch-)-.25 F 3.07
(ing. Each)102 289.2 R .57(address is mark)3.07 F .57
(ed as it is sent so rescanning the list is safe.)-.1 F .57(An ar)5.57 F .57
(gument list is b)-.18 F .57(uilt as)-.2 F 1.138(the scan proceeds.)102 301.2 R
1.139(Mail to \214les is detected during the scan of the send list.)6.139 F
1.139(The interf)6.139 F 1.139(ace to the)-.1 F
(mailer is performed using one of the techniques described in section 2.2.)102
313.2 Q .996(After a connection is established,)127 329.4 R/F2 10
/Times-Italic@0 SF(sendmail)3.496 E F1(mak)3.495 E .995(es the per)-.1 F .995
(-mailer changes to the header and)-.2 F .236(sends the result to the mailer)
102 341.4 R 5.236(.I)-.55 G 2.736(fa)228.406 341.4 S .537 -.15(ny m)238.912
341.4 T .237(ail is rejected by the mailer).15 F 2.737(,a\215)-.4 G .237
(ag is set to in)386.628 341.4 R -.2(vo)-.4 G .437 -.1(ke t).2 H .237
(he return-).1 F(to-sender function after all deli)102 353.4 Q -.15(ve)-.25 G
(ry completes.).15 E F0 2.5(3.6. Queued)87 377.4 R(Messages)2.5 E F1 .163
(If the mailer returns a \231temporary f)127 393.6 R .163(ailure\232 e)-.1 F
.162(xit status, the message is queued.)-.15 F 2.662(Ac)5.162 G .162
(ontrol \214le is)455.336 393.6 R .85
(used to describe the recipients to be sent to and v)102 405.6 R .851
(arious other parameters.)-.25 F .851(This control \214le is for)5.851 F(-)-.2
E 1.011(matted as a series of lines, each describing a sender)102 417.6 R 3.511
(,ar)-.4 G 1.011(ecipient, the time of submission, or some)333.494 417.6 R .776
(other salient parameter of the message.)102 429.6 R .776
(The header of the message is stored in the control \214le, so)5.776 F(that th\
e associated data \214le in the queue is just the temporary \214le that w)102
441.6 Q(as originally collected.)-.1 E F0 2.5(3.7. Con\214guration)87 465.6 R
F1 .493(Con\214guration is controlled primarily by a con\214guration \214le re\
ad at startup.)127 481.8 R F2(Sendmail)5.492 E F1(should)2.992 E
(not need to be recomplied e)102 493.8 Q(xcept)-.15 E 12.5(\(1\) T)107 510 R
2.5(oc)-.8 G(hange operating systems \(V6, V7/32V)150.91 510 Q 2.5(,4)-1.29 G
(BSD\).)313.21 510 Q 12.5(\(2\) T)107 526.2 R 2.5(or)-.8 G(emo)149.8 526.2 Q .3
-.15(ve o)-.15 H 2.5(ri).15 G(nsert the DBM \(UNIX database\) library)192.27
526.2 Q(.)-.65 E 12.5(\(3\) T)107 542.4 R 2.5(oc)-.8 G(hange ARP)150.91 542.4 Q
(ANET reply codes.)-.92 E 12.5(\(4\) T)107 558.6 R 2.5(oa)-.8 G
(dd headers \214elds requiring special processing.)150.91 558.6 Q .434
(Adding mailers or changing parsing \(i.e., re)102 574.8 R .435
(writing\) or routing information does not require recom-)-.25 F(pilation.)102
586.8 Q 1.317(If the mail is being sent by a local user)127 603 R 3.817(,a)-.4
G 1.317(nd the \214le \231.mailcf\232 e)303.914 603 R 1.317
(xists in the sender')-.15 F 3.817(sh)-.55 G(ome)486.78 603 Q(directory)102 615
Q 2.721(,t)-.65 G .221(hat \214le is read as a con\214guration \214le after th\
e system con\214guration \214le.)145.451 615 R .222(The primary use)5.222 F
(of this feature is to add header lines.)102 627 Q 3.25(The con\214guration \
\214le encodes macro de\214nitions, header de\214nitions, mailer de\214nitions\
,)127 643.2 R(re)102 655.2 Q(writing rules, and options.)-.25 E F0 2.5
(3.7.1. Macr)102 679.2 R(os)-.18 E F1 .332(Macros can be used in three w)142
695.4 R 2.833(ays. Certain)-.1 F .333(macros transmit unstructured te)2.833 F
.333(xtual informa-)-.15 F .07(tion into the mail system, such as the name)117
707.4 R F2(sendmail)2.57 E F1 .07
(will use to identify itself in error messages.)2.57 F 1.247
(Other macros transmit information from)117 719.4 R F2(sendmail)3.747 E F1
1.247(to the con\214guration \214le for use in creating)3.747 F EP
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/F0 10/Times-Bold@0 SF 192.28(SMM:9-8 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/F1 10
/Times-Roman@0 SF .312(other \214elds \(such as ar)117 96 R .312(gument v)-.18
F .312(ectors to mailers\); e.g., the name of the sender)-.15 F 2.811(,a)-.4 G
.311(nd the host and)442.237 96 R .848(user of the recipient.)117 108 R .848
(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(tef@ucsfcgl.UUCP)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
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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)87 369 R .545
(feeling is not born out by our e)3.045 F .545(xperience; on the contrary)-.15
F 3.045(,t)-.65 G .545(he location and format of mail-)376.575 369 R(box)87 381
Q(es seems to v)-.15 E(ary widely from system to system.)-.25 E .681
(The ability to automatically generate a response to incoming mail \(by forw)
112 397.2 R .68(arding mail to a pro-)-.1 F .435
(gram\) seems useful \(\231I am on v)87 409.2 R .435
(acation until late August....)-.25 F 2.935(\232\) b)-.7 F .435
(ut can create problems such as forw)-.2 F(ard-)-.1 E .143(ing loops \(tw)87
421.2 R 2.643(op)-.1 G .143(eople on v)152.609 421.2 R .143(acation whose prog\
rams send notes back and forth, for instance\) if these pro-)-.25 F .732
(grams are not well written.)87 433.2 R 3.232(Ap)5.732 G .732
(rogram could be written to do standard tasks correctly)218.592 433.2 R 3.233
(,b)-.65 G .733(ut this w)450.404 433.2 R(ould)-.1 E(solv)87 445.2 Q 2.5(et)
-.15 G(he general case.)113.24 445.2 Q .225
(It might be desirable to implement some form of load limiting.)112 461.4 R
2.725(Ia)5.225 G 2.724(mu)380.8 461.4 S(na)396.304 461.4 Q -.1(wa)-.15 G .224
(re of an).1 F 2.724(ym)-.15 G .224(ail system)463.496 461.4 R
(that addresses this problem, nor am I a)87 473.4 Q -.1(wa)-.15 G(re of an).1 E
2.5(yr)-.15 G(easonable solution at this time.)294.05 473.4 Q .113(The con\214\
guration \214le is currently practically inscrutable; considerable con)112
489.6 R -.15(ve)-.4 G .114(nience could be real-).15 F(ized with a higher)87
501.6 Q(-le)-.2 E -.15(ve)-.25 G 2.5(lf).15 G(ormat.)186.93 501.6 Q .778(It se\
ems clear that common protocols will be changing soon to accommodate changing \
require-)112 517.8 R 2.774(ments and en)87 529.8 R 5.274(vironments. These)-.4
F 2.774(changes will include modi\214cations to the message header \(e.g.,)
5.274 F .859([NBS80]\) or to the body of the message itself \(such as for mult\
imedia messages [Postel80]\).)87 541.8 R(Experi-)5.859 E
(ence indicates that these changes should be relati)87 553.8 Q -.15(ve)-.25 G
(ly tri).15 E(vial to inte)-.25 E(grate into the e)-.15 E(xisting system.)-.15
E .811(In tightly coupled en)112 570 R .812(vironments, it w)-.4 F .812
(ould be nice to ha)-.1 F 1.112 -.15(ve a n)-.2 H .812(ame serv).15 F .812
(er such as Grapvine [Bir)-.15 F(-)-.2 E .095(rell82] inte)87 582 R .095
(grated into the mail system.)-.15 F .095(This w)5.095 F .095(ould allo)-.1 F
2.594(was)-.25 G .094(ite such as \231Berk)330.768 582 R(ele)-.1 E .094
(y\232 to appear as a single)-.15 F 2.606
(host, rather than as a collection of hosts, and w)87 594 R 2.606(ould allo)-.1
F 5.106(wp)-.25 G 2.606(eople to mo)352.786 594 R 2.906 -.15(ve t)-.15 H 2.606
(ransparently among).15 F 1.664(machines without ha)87 606 R 1.664
(ving to change their addresses.)-.2 F 1.664(Such a f)6.664 F 1.664(acility w)
-.1 F 1.663(ould require an automatically)-.1 F .428
(updated database and some method of resolving con\215icts.)87 618 R .428
(Ideally this w)5.428 F .428(ould be ef)-.1 F(fecti)-.25 E .728 -.15(ve e)-.25
H -.15(ve)-.1 G 2.928(nw).15 G(ithout)480.66 618 Q .184
(all hosts being under a single management.)87 630 R(Ho)5.184 E(we)-.25 E -.15
(ve)-.25 G .984 -.4(r, i).15 H 2.684(ti).4 G 2.683(sn)317.576 630 S .183
(ot clear whether this feature should be inte-)329.149 630 R
(grated into the aliasing f)87 642 Q(acility or should be considered a \231v)
-.1 E(alue added\232 feature outside)-.25 E F1(sendmail)2.5 E F2(itself.)2.5 E
.79(As a more interesting case, the CSNET name serv)112 658.2 R .791
(er [Solomon81] pro)-.15 F .791(vides an f)-.15 F .791(acility that goes)-.1 F
(be)87 670.2 Q .375(yond a single tightly-coupled en)-.15 F 2.875
(vironment. Such)-.4 F 2.875(af)2.875 G .375(acility w)308.675 670.2 R .374
(ould normally e)-.1 F .374(xist outside of)-.15 F F1(sendmail)2.874 E F2(ho)87
682.2 Q(we)-.25 E -.15(ve)-.25 G -.55(r.).15 G 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:9-11)457.9 60 Q -.55(AC)72 96 S(KNO).55 E
(WLEDGEMENTS)-.5 E/F1 10/Times-Roman@0 SF 1.203(Thanks are due to K)97 112.2 R
1.204
(urt Shoens for his continual cheerful assistance and good advice, Bill Jo)-.15
F 3.704(yf)-.1 G(or)495.67 112.2 Q .102
(pointing me in the correct direction \(o)72 124.2 R -.15(ve)-.15 G 2.602(ra)
.15 G .102(nd o)244.324 124.2 R -.15(ve)-.15 G .102
(r\), and Mark Horton for more advice, prodding, and man).15 F(y)-.15 E .453
(of the good ideas.)72 136.2 R -.15(Ku)5.453 G .453
(rt and Eric Schmidt are to be credited for using).15 F/F2 10/Times-Italic@0 SF
(delivermail)2.953 E F1 .453(as a serv)2.953 F .453(er for their pro-)-.15 F
1.663(grams \()72 148.2 R F2(Mail)A F1 1.663(and BerkNet respecti)4.163 F -.15
(ve)-.25 G 1.663(ly\) before an).15 F 4.163(ys)-.15 G 1.663
(ane person should ha)291.091 148.2 R -.15(ve)-.2 G 4.163(,a).15 G 1.662
(nd making the necessary)400.423 148.2 R .078
(modi\214cations promptly and happily)72 160.2 R 5.078(.E)-.65 G .078(ric g)
228.332 160.2 R -2.25 -.2(av e)-.05 H .079
(me considerable advice about the perils of netw)2.778 F .079(ork softw)-.1 F
(are)-.1 E .179(which sa)72 172.2 R -.15(ve)-.2 G 2.679(dm).15 G 2.679(ea)
131.998 172.2 S 2.679(nu)143.557 172.2 S(nkno)156.236 172.2 Q .178
(wn amount of w)-.25 F .178(ork and grief.)-.1 F .178
(Mark did the original implementation of the DBM)5.178 F -.15(ve)72 184.2 S
.341(rsion of aliasing, installed the VFORK code, wrote the current v).15 F
.341(ersion of)-.15 F F2(rmail)2.841 E F1 2.841(,a)C .341(nd w)411.083 184.2 R
.342(as the person who)-.1 F .61(really con)72 196.2 R .61
(vinced me to put the w)-.4 F .61(ork into)-.1 F F2(delivermail)3.109 E F1 .609
(to turn it into)3.109 F F2(sendmail)3.109 E F1 5.609(.K)C .609(urt deserv)
398.753 196.2 R .609(es accolades for)-.15 F(using)72 208.2 Q F2(sendmail)2.57
E F1 .07(when I w)2.57 F .07(as myself afraid to tak)-.1 F 2.57(et)-.1 G .07
(he risk; ho)271.01 208.2 R 2.57(wap)-.25 G .07
(erson can continue to be so enthusiastic in)334.92 208.2 R(the f)72 220.2 Q
(ace of so much bitter reality is be)-.1 E(yond me.)-.15 E -.15(Ku)97 236.4 S
1.505(rt, Mark, Kirk McK).15 F 1.505(usick, Marvin Solomon, and man)-.15 F
4.005(yo)-.15 G 1.504(thers ha)345.79 236.4 R 1.804 -.15(ve r)-.2 H -.25(ev).15
G(ie).25 E 1.504(wed this paper)-.25 F 4.004(,g)-.4 G -.25(iv)483.69 236.4 S
(ing).25 E(considerable useful advice.)72 248.4 Q .846
(Special thanks are reserv)97 264.6 R .846(ed for Mik)-.15 F 3.346(eS)-.1 G
(tonebrak)256.786 264.6 Q .846(er at Berk)-.1 F(ele)-.1 E 3.347(ya)-.15 G .847
(nd Bob Epstein at Britton-Lee, who)356.995 264.6 R .542(both kno)72 276.6 R
.542(wingly allo)-.25 F .542(wed me to put so much w)-.25 F .541
(ork into this project when there were so man)-.1 F 3.041(yo)-.15 G .541
(ther things I)454.588 276.6 R(really should ha)72 288.6 Q .3 -.15(ve b)-.2 H
(een w).15 E(orking on.)-.1 E EP
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/F0 10/Times-Roman@0 SF(REFERENCES)256.605 132 Q 62.73([Birrell82] Birrell,)72
148.2 R 1.084(A. D., Le)3.584 F 1.084(vin, R., Needham, R. M., and Schroeder)
-.25 F 3.584(,M)-.4 G 3.585(.D)433.49 148.2 S 1.085(., \231Grape)446.795 148.2
R(vine:)-.25 E(An Ex)180 160.2 Q(ercise in Distrib)-.15 E(uted Computing.)-.2 E
5<9a49>-.7 G(n)348.66 160.2 Q/F1 10/Times-Italic@0 SF(Comm. A.C.M. 25,)2.5 E F0
(4, April 82.)2.5 E 59.4([Borden79] Borden,)72 176.4 R .796
(S., Gaines, R. S., and Shapiro, N. Z.,)3.296 F F1 .795(The MH Messa)3.295 F
.995 -.1(ge H)-.1 H .795(andling Sys-).1 F(tem: User)180 188.4 Q(s' Manual.)-.1
E F0(R-2367-P)5 E(AF)-.92 E 5(.R)-.8 G(and Corporation.)332.06 188.4 Q
(October 1979.)5 E([Crock)72 204.6 Q 52.29(er77a] Crock)-.1 F(er)-.1 E 2.508
(,D)-.4 G 2.508(.H)223.938 204.6 S .008(., V)236.166 204.6 R .009
(ittal, J. J., Pogran, K. T)-.6 F .009(., and Henderson, D. A. Jr)-.74 F(.,)
-.55 E F1(Standar)2.509 E 2.509(df)-.37 G(or)495.11 204.6 Q .955(the F)180
216.6 R .955(ormat of ARP)-1.05 F 3.454(AN)-.9 G .954(etwork T)272.978 216.6 R
-.2(ex)-.92 G 3.454(tM).2 G(essa)331.536 216.6 Q -.1(ge)-.1 G(s.).1 E F0 .954
(RFC 733, NIC 41952.)5.954 F .954(In [Fein-)5.954 F 2.5(ler78]. No)180 228.6 R
-.15(ve)-.15 G(mber 1977.).15 E([Crock)72 244.8 Q 51.73(er77b] Crock)-.1 F(er)
-.1 E 3.04(,D)-.4 G 3.04(.H)224.47 244.8 S(.,)237.23 244.8 Q F1 -1.55 -.55
(Fr a)3.04 H(me).55 E .54(work and Functions of the MS P)-.15 F(er)-.8 E .54
(sonal Messa)-.1 F .74 -.1(ge S)-.1 H(ystem.).1 E F0(R-2134-ARP)180 256.8 Q
(A, Rand Corporation, Santa Monica, California.)-.92 E(1977.)5 E([Crock)72 273
Q 56.73(er79] Crock)-.1 F(er)-.1 E 2.557(,D)-.4 G 2.557(.H)223.987 273 S .056
(., Szurk)236.264 273 R -.25(ow)-.1 G .056(ski, E. S., and F).25 F(arber)-.15 E
2.556(,D)-.4 G 2.556(.J)374.85 273 S(.,)383.796 273 Q F1 .056
(An Internetwork Memo Dis-)2.556 F(trib)180 285 Q 1.341(ution F)-.2 F 1.341
(acility \212 MMDF)-.75 F(.)-1.35 E F0 1.341
(6th Data Communication Symposium, Asilomar)6.341 F(.)-.55 E(No)180 297 Q -.15
(ve)-.15 G(mber 1979.).15 E([Crock)72 313.2 Q 56.73(er82] Crock)-.1 F(er)-.1 E
3.383(,D)-.4 G 3.383(.H)224.813 313.2 S(.,)237.916 313.2 Q F1(Standar)3.383 E
3.383(df)-.37 G .883(or the F)288.762 313.2 R .882(ormat of Arpa Internet T)
-1.05 F -.2(ex)-.92 G 3.382(tM).2 G(essa)446.368 313.2 Q -.1(ge)-.1 G(s.).1 E
F0(RFC)5.882 E 4.197(822. Netw)180 325.2 R 1.697(ork Information Center)-.1 F
4.197(,S)-.4 G 1.698(RI International, Menlo P)333.768 325.2 R 1.698
(ark, California.)-.15 F(August 1982.)180 337.2 Q 53.3([Metcalfe76] Metcalfe,)
72 353.4 R .727(R., and Boggs, D., \231Ethernet: Distrib)3.227 F .727(uted P)
-.2 F(ack)-.15 E .727(et Switching for Local)-.1 F(Computer Netw)180 365.4 Q
(orks\232,)-.1 E F1(Communications of the A)2.5 E(CM 19,)-.3 E F0 2.5(7. July)
2.5 F(1976.)2.5 E 60.51([Feinler78] Feinler)72 381.6 R 4.438(,E)-.4 G 1.938
(., and Postel, J.)220.978 381.6 R(\(eds.\),)6.938 E F1(ARP)4.438 E 1.938
(ANET Pr)-.9 F 1.938(otocol Handbook.)-.45 F F0 1.938(NIC 7104,)6.938 F(Netw)
180 393.6 Q(ork Information Center)-.1 E 2.5(,S)-.4 G
(RI International, Menlo P)304.48 393.6 Q(ark, California.)-.15 E(1978.)5 E
69.39([NBS80] National)72 409.8 R 1.46(Bureau of Standards,)3.96 F F1 1.46
(Speci\214cation of a Dr)3.96 F 1.46(aft Messa)-.15 F 1.66 -.1(ge F)-.1 H 1.46
(ormat Stan-)-.95 F(dar)180 421.8 Q(d.)-.37 E F0(Report No. ICST/CBOS 80-2.)5 E
(October 1980.)5 E 60.51([Neigus73] Neigus,)72 438 R(N.,)5.186 E F1 -.45(Fi)
5.186 G 2.686(le T).45 F -.15(ra)-.55 G 2.686(nsfer Pr).15 F 2.686
(otocol for the ARP)-.45 F 5.187(AN)-.9 G(etwork.)402.599 438 Q F0 2.687
(RFC 542, NIC)7.687 F 2.5(17759. In)180 450 R 2.5([Feinler78]. August,)2.5 F
(1973.)2.5 E([No)72 466.2 Q 55.21(witz78a] No)-.25 F 1.633
(witz, D. A., and Lesk, M. E.,)-.25 F F1 4.132(AD)4.132 G 1.632
(ial-Up Network of UNIX Systems.)338.9 466.2 R F0(Bell)6.632 E 5.403
(Laboratories. In)180 478.2 R 2.904(UNIX Programmer')5.403 F 5.404(sM)-.55 G
2.904(anual, Se)356.024 478.2 R -.15(ve)-.25 G 2.904(nth Edition, V).15 F 2.904
(olume 2.)-1.29 F(August, 1978.)180 490.2 Q([No)72 506.4 Q 54.65(witz78b] No)
-.25 F .633(witz, D. A.,)-.25 F F1 .632(Uucp Implementation Description.)3.132
F F0 .632(Bell Laboratories.)5.632 F .632(In UNIX)5.632 F(Programmer')180 518.4
Q 2.5(sM)-.55 G(anual, Se)248.05 518.4 Q -.15(ve)-.25 G(nth Edition, V).15 E
(olume 2.)-1.29 E(October)5 E 2.5(,1)-.4 G(978.)431.22 518.4 Q 64.39
([Postel74] Postel,)72 534.6 R .24(J., and Neigus, N., Re)2.74 F .241
(vised FTP Reply Codes.)-.25 F .241(RFC 640, NIC 30843.)5.241 F(In)5.241 E 2.5
([Feinler78]. June,)180 546.6 R(1974.)2.5 E 64.39([Postel77] Postel,)72 562.8 R
(J.,)2.5 E F1(Mail Pr)2.5 E(otocol.)-.45 E F0(NIC 29588.)5 E(In [Feinler78].)5
E(No)5 E -.15(ve)-.15 G(mber 1977.).15 E 59.95([Postel79a] Postel,)72 579 R
(J.,)3.144 E F1 .644(Internet Messa)3.144 F .844 -.1(ge P)-.1 H -.45(ro).1 G
(tocol.).45 E F0 .644(RFC 753, IEN 85.)5.644 F(Netw)5.644 E .644
(ork Information)-.1 F(Center)180 591 Q 2.5(,S)-.4 G(RI International, Menlo P)
216.82 591 Q(ark, California.)-.15 E(March 1979.)5 E 59.39([Postel79b] Postel,)
72 607.2 R 1.305(J. B.,)3.805 F F1 1.305(An Internetwork Messa)3.805 F 1.505
-.1(ge S)-.1 H(tructur).1 E -.15(e.)-.37 G F0(In)6.456 E F1(Pr)3.806 E 1.306
(oceedings of the Sixth)-.45 F(Data Communications Symposium,)180 619.2 Q F0
2.5(IEEE. Ne)2.5 F 2.5(wY)-.25 G 2.5(ork. No)379.74 619.2 R -.15(ve)-.15 G
(mber 1979.).15 E 64.39([Postel80] Postel,)72 635.4 R .639(J. B.,)3.139 F F1
3.139(AS)3.139 G(tructur)248.676 635.4 Q .639(ed F)-.37 F .639(ormat for T)
-1.05 F -.15(ra)-.55 G .639(nsmission of Multi-Media Documents.).15 F F0 .418
(RFC 767.)180 647.4 R(Netw)5.419 E .419(ork Information Center)-.1 F 2.919(,S)
-.4 G .419(RI International, Menlo P)350.474 647.4 R .419(ark, Califor)-.15 F
(-)-.2 E 2.5(nia. August)180 659.4 R(1980.)2.5 E 64.39([Postel82] Postel,)72
675.6 R 2.05(J. B.,)4.55 F F1 2.05(Simple Mail T)4.55 F -.15(ra)-.55 G 2.05
(nsfer Pr).15 F(otocol.)-.45 E F0 2.05(RFC821 \(obsoleting RFC788\).)7.05 F
(Netw)180 687.6 Q .273(ork Information Center)-.1 F 2.774(,S)-.4 G .274
(RI International, Menlo P)305.3 687.6 R .274(ark, California.)-.15 F(August)
5.274 E(1982.)180 699.6 Q/F2 10/Times-Bold@0 SF 187.28(SMM:9-12 SENDMAIL)72 756
R 2.5<8a41>2.5 G 2.5(nI)383.99 756 S(nter)395.94 756 Q(netw)-.15 E
(ork Mail Router)-.1 E 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:9-13)457.9 60 Q/F1 10/Times-Roman@0 SF 55.5
([Schmidt79] Schmidt,)72 96 R(E.,)2.972 E/F2 10/Times-Italic@0 SF .472(An Intr)
2.972 F .472(oduction to the Berk)-.45 F(ele)-.1 E 2.972(yN)-.3 G(etwork.)
369.664 96 Q F1(Uni)5.472 E -.15(ve)-.25 G .472(rsity of California,).15 F
(Berk)180 108 Q(ele)-.1 E 2.5(yC)-.15 G 2.5(alifornia. 1979.)225.02 108 R 59.95
([Shoens79] Shoens,)72 124.2 R(K.,)4.894 E F2 2.394(Mail Refer)4.894 F 2.394
(ence Manual.)-.37 F F1(Uni)7.394 E -.15(ve)-.25 G 2.395
(rsity of California, Berk).15 F(ele)-.1 E 6.195 -.65(y. I)-.15 H(n).65 E
(UNIX Programmer')180 136.2 Q 2.5(sM)-.55 G(anual, Se)275.54 136.2 Q -.15(ve)
-.25 G(nth Edition, V).15 E(olume 2C.)-1.29 E(December 1979.)5 E 60.51
([Sluizer81] Sluizer)72 152.4 R 2.872(,S)-.4 G .372(., and Postel, J. B.,)
218.862 152.4 R F2 .372(Mail T)2.872 F -.15(ra)-.55 G .372(nsfer Pr).15 F
(otocol.)-.45 E F1 .371(RFC 780.)5.371 F(Netw)5.371 E .371(ork Infor)-.1 F(-)
-.2 E(mation Center)180 164.4 Q 2.5(,S)-.4 G(RI International, Menlo P)247.1
164.4 Q(ark, California.)-.15 E(May 1981.)5 E 52.72([Solomon81] Solomon,)72
180.6 R .96(M., Landweber)3.46 F 3.46(,L)-.4 G .96
(., and Neuhengen, D., \231The Design of the CSNET)296.08 180.6 R(Name Serv)180
192.6 Q(er)-.15 E 3.9 -.7(.\232 C)-.55 H(S-DN-2, Uni).7 E -.15(ve)-.25 G
(rsity of W).15 E(isconsin, Madison.)-.4 E(No)5 E -.15(ve)-.15 G(mber 1981.).15
E 78.28([Su82] Su,)72 208.8 R(Za)4.344 E 1.844(w-Sing, and Postel, Jon,)-.15 F
F2 1.844(The Domain Naming Con)4.344 F 1.844(vention for Internet)-.4 F 1.717
(User Applications.)180 220.8 R F1 4.217(RFC819. Netw)6.717 F 1.717
(ork Information Center)-.1 F 4.217(,S)-.4 G 1.718(RI International,)436.182
220.8 R(Menlo P)180 232.8 Q(ark, California.)-.15 E(August 1982.)5 E([UNIX83])
72 249 Q F2 2.12(The UNIX Pr)180 249 R -.1(og)-.45 G -.15(ra).1 G(mmer').15 E
4.62(sM)-.4 G 2.12(anual, Se)298.3 249 R 2.12(venth Edition,)-.15 F F1 -.6(Vi)
4.62 G 2.12(rtual V).6 F 2.12(AX-11 V)-1.35 F(ersion,)-1.11 E -1.29(Vo)180 261
S 1.027(lume 1.)1.29 F 1.027(Bell Laboratories, modi\214ed by the Uni)6.027 F
-.15(ve)-.25 G 1.027(rsity of California, Berk).15 F(e-)-.1 E(le)180 273 Q 1.3
-.65(y, C)-.15 H 2.5(alifornia. March,).65 F(1983.)2.5 E EP
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