usenix.ps

早期freebsd实现

(ferent format to)-.25 F -.2(bu)118.66 148.2 S .25(ild their en).2 F .25
(vironment without changing the system, and f)-.4 F .25
(acilitates specialized functions \(such)-.1 F(as returning an \231I am on v)
118.66 160.2 Q(acation\232 message\).)-.25 E 12.5(\(8\) Netw)92 176.4 R 1.552
(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)118.66 188.4 Q
(.)-.55 E .375(These goals moti)112 204.6 R -.25(va)-.25 G .375
(ted the architecture illustrated in \214gure 1.).25 F .374
(The user interacts with a mail gen-)5.375 F .49(erating and sending program.)
87 216.6 R .491(When the mail is created, the generator calls)5.49 F F2
(sendmail)2.991 E F1 2.991(,w)C .491(hich routes the)444.138 216.6 R .841
(message to the correct mailer\(s\).)87 228.6 R .841
(Since some of the senders may be netw)5.841 F .84(ork serv)-.1 F .84
(ers and some of the)-.15 F(mailers may be netw)87 240.6 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 F0 2.5(3. USA)72 264.6 R(GE)-.55 E 2.5(3.1. Addr)87 288.6 R
(ess F)-.18 E(ormats)-.25 E F1(Ar)127 304.8 Q .886
(guments may be \215ags or addresses.)-.18 F .886(Flags set v)5.886 F .886
(arious processing options.)-.25 F -.15(Fo)5.886 G(llo).15 E .886(wing \215ag)
-.25 F(ar)102 316.8 Q .611(guments, address ar)-.18 F .611(guments may be gi)
-.18 F -.15(ve)-.25 G 3.111(n. Addresses).15 F(follo)3.111 E 3.111(wt)-.25 G
.611(he syntax in RFC822 [Crock)365.558 316.8 R(er82])-.1 E(for ARP)102 328.8 Q
(ANET address formats.)-.92 E(In brief, the format is:)5 E 12.5(\(1\) An)107
345 R(ything in parentheses is thro)-.15 E(wn a)-.25 E -.1(wa)-.15 G 2.5(y\().1
G(as a comment\).)299.65 345 Q 12.5(\(2\) An)107 361.2 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
361.2 S .051(thing else.).15 F .051(This rule implements the)5.051 F(ARP)133.66
373.2 Q(ANET standard that addresses of the form)-.92 E .4 LW 77 408 72 408 DL
79 408 74 408 DL 84 408 79 408 DL 89 408 84 408 DL 94 408 89 408 DL 99 408 94
408 DL 104 408 99 408 DL 109 408 104 408 DL 114 408 109 408 DL 119 408 114 408
DL 124 408 119 408 DL 129 408 124 408 DL 134 408 129 408 DL 139 408 134 408 DL
144 408 139 408 DL 149 408 144 408 DL 154 408 149 408 DL 159 408 154 408 DL 164
408 159 408 DL 169 408 164 408 DL 174 408 169 408 DL 179 408 174 408 DL 184 408
179 408 DL 189 408 184 408 DL 194 408 189 408 DL 199 408 194 408 DL 204 408 199
408 DL 209 408 204 408 DL 214 408 209 408 DL 219 408 214 408 DL 224 408 219 408
DL 229 408 224 408 DL 234 408 229 408 DL 239 408 234 408 DL 244 408 239 408 DL
249 408 244 408 DL 254 408 249 408 DL 259 408 254 408 DL 264 408 259 408 DL 269
408 264 408 DL 274 408 269 408 DL 279 408 274 408 DL 284 408 279 408 DL 289 408
284 408 DL 294 408 289 408 DL 299 408 294 408 DL 304 408 299 408 DL 309 408 304
408 DL 314 408 309 408 DL 319 408 314 408 DL 324 408 319 408 DL 329 408 324 408
DL 334 408 329 408 DL 339 408 334 408 DL 344 408 339 408 DL 349 408 344 408 DL
354 408 349 408 DL 359 408 354 408 DL 364 408 359 408 DL 369 408 364 408 DL 374
408 369 408 DL 379 408 374 408 DL 384 408 379 408 DL 389 408 384 408 DL 394 408
389 408 DL 399 408 394 408 DL 404 408 399 408 DL 409 408 404 408 DL 414 408 409
408 DL 419 408 414 408 DL 424 408 419 408 DL 429 408 424 408 DL 434 408 429 408
DL 439 408 434 408 DL 444 408 439 408 DL 449 408 444 408 DL 454 408 449 408 DL
459 408 454 408 DL 464 408 459 408 DL 469 408 464 408 DL 474 408 469 408 DL 479
408 474 408 DL 484 408 479 408 DL 489 408 484 408 DL 494 408 489 408 DL 499 408
494 408 DL 504 408 499 408 DL(Figure 1 \212 Sendmail System Structure.)208 660
Q 77 672 72 672 DL 79 672 74 672 DL 84 672 79 672 DL 89 672 84 672 DL 94 672 89
672 DL 99 672 94 672 DL 104 672 99 672 DL 109 672 104 672 DL 114 672 109 672 DL
119 672 114 672 DL 124 672 119 672 DL 129 672 124 672 DL 134 672 129 672 DL 139
672 134 672 DL 144 672 139 672 DL 149 672 144 672 DL 154 672 149 672 DL 159 672
154 672 DL 164 672 159 672 DL 169 672 164 672 DL 174 672 169 672 DL 179 672 174
672 DL 184 672 179 672 DL 189 672 184 672 DL 194 672 189 672 DL 199 672 194 672
DL 204 672 199 672 DL 209 672 204 672 DL 214 672 209 672 DL 219 672 214 672 DL
224 672 219 672 DL 229 672 224 672 DL 234 672 229 672 DL 239 672 234 672 DL 244
672 239 672 DL 249 672 244 672 DL 254 672 249 672 DL 259 672 254 672 DL 264 672
259 672 DL 269 672 264 672 DL 274 672 269 672 DL 279 672 274 672 DL 284 672 279
672 DL 289 672 284 672 DL 294 672 289 672 DL 299 672 294 672 DL 304 672 299 672
DL 309 672 304 672 DL 314 672 309 672 DL 319 672 314 672 DL 324 672 319 672 DL
329 672 324 672 DL 334 672 329 672 DL 339 672 334 672 DL 344 672 339 672 DL 349
672 344 672 DL 354 672 349 672 DL 359 672 354 672 DL 364 672 359 672 DL 369 672
364 672 DL 374 672 369 672 DL 379 672 374 672 DL 384 672 379 672 DL 389 672 384
672 DL 394 672 389 672 DL 399 672 394 672 DL 404 672 399 672 DL 409 672 404 672
DL 414 672 409 672 DL 419 672 414 672 DL 424 672 419 672 DL 429 672 424 672 DL
434 672 429 672 DL 439 672 434 672 DL 444 672 439 672 DL 449 672 444 672 DL 454
672 449 672 DL 459 672 454 672 DL 464 672 459 672 DL 469 672 464 672 DL 474 672
469 672 DL 479 672 474 672 DL 484 672 479 672 DL 489 672 484 672 DL 494 672 489
672 DL 499 672 494 672 DL 504 672 499 672 DL F0 -1(Ve)72 756 S(rsion 8.2)1 E
(USENIX \255 J)249.805 756 Q(an 83)-.15 E(Last Mod 11/27/93)424.55 756 Q EP
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/F0 10/Times-Bold@0 SF(Mail Systems and Addr)72 60 Q(essing in 4.2bsd)-.18 E(5)
499 60 Q/F1 10/Times-Roman@0 SF(user name <machine-address>)173.66 96 Q(will s\
end to the electronic \231machine-address\232 rather than the human \231user n\
ame.)133.66 112.2 Q<9a>-.7 E 12.5(\(3\) Double)107 128.4 R 2.246(quotes \()
4.746 F -2.754 2.5("\) q)2.5 H 2.246
(uote phrases; backslashes quote characters.)224.188 128.4 R 2.246
(Backslashes are more)7.246 F(po)133.66 140.4 Q .654(werful in that the)-.25 F
3.154(yw)-.15 G .655(ill cause otherwise equi)229.196 140.4 R -.25(va)-.25 G
.655(lent phrases to compare dif).25 F .655(ferently \212 for)-.25 F -.15(ex)
133.66 152.4 S(ample,).15 E/F2 10/Times-Italic@0 SF(user)3.873 E F1(and)3.873 E
F2("user")3.872 E F1 1.372(are equi)3.872 F -.25(va)-.25 G 1.372(lent, b).25 F
(ut)-.2 E F2(\\user)3.872 E F1 1.372(is dif)3.872 F 1.372
(ferent from either of them.)-.25 F(This)6.372 E(might be used to a)133.66
164.4 Q -.2(vo)-.2 G(id normal aliasing or duplicate suppression algorithms.).2
E -.15(Pa)127 180.6 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)102 194.6 Q(writing rules control remaining parsing)-.25 E/F3 7
/Times-Roman@0 SF(2)266.17 190.6 Q F1(.)269.67 194.6 Q .644(Although old style\
 addresses are still accepted in most cases, the preferred address format is)
127 210.8 R .299(based on ARP)102 222.8 R(ANET)-.92 E .299
(-style domain-based addresses [Su82a].)-.92 F .299
(These addresses are based on a hierar)5.299 F(-)-.2 E .13
(chical, logical decomposition of the address space.)102 234.8 R .13
(The addresses are hierarchical in a sense similar)5.13 F 1.133(to the U.S. po\
stal addresses: the messages may \214rst be routed to the correct state, with \
no initial)102 246.8 R .72
(consideration of the city or other addressing details.)102 258.8 R .72
(The addresses are logical in that each step in)5.72 F(the hierarch)102 270.8 Q
2.5(yc)-.05 G
(orresponds to a set of \231naming authorities\232 rather than a ph)161.37
270.8 Q(ysical netw)-.05 E(ork.)-.1 E -.15(Fo)127 287 S 2.5(re).15 G
(xample, the address:)147.53 287 Q([e-mail])142 303.2 Q(A)-.92 E
-.1(wo)102 319.4 S .851
(uld \214rst look up the domain BigSite in the namespace administrated by ARP)
.1 F 3.351(A. A)-.92 F .851(query could)3.351 F 1.476
(then be sent to BigSite for interpretation of HostA.)102 331.4 R(Ev)6.475 E
1.475(entually the mail w)-.15 F 1.475(ould arri)-.1 F 1.775 -.15(ve a)-.25 H
3.975(tH).15 G(ostA,)482.61 331.4 Q(which w)102 343.4 Q
(ould then do \214nal deli)-.1 E -.15(ve)-.25 G(ry to user \231eric.).15 E<9a>
-.7 E F0 2.5(3.2. Mail)87 367.4 R(to Files and Pr)2.5 E(ograms)-.18 E F1 .609
(Files and programs are le)127 383.6 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-)445.02 383.6 R .124
(sages, useful for project administration and history)102 395.6 R 5.124(.P)-.65
G .124(rograms are useful as recipients in a v)318.308 395.6 R .124(ariety of)
-.25 F .69(situations, for e)102 407.6 R .691(xample, to maintain a public rep\
ository of systems messages \(such as the Berk)-.15 F(ele)-.1 E(y)-.15 E F2
(msgs)102 419.6 Q F1(program\).)2.5 E(An)127 435.8 Q 3.188(ya)-.15 G .688(ddre\
ss passing through the initial parsing algorithm as a local address \(i.e, not\
 appear)151.698 435.8 R(-)-.2 E .276(ing to be a v)102 447.8 R .276
(alid address for another mailer\) is scanned for tw)-.25 F 2.776(os)-.1 G .277
(pecial cases.)362.128 447.8 R .277(If pre\214x)5.277 F .277(ed by a v)-.15 F
(erti-)-.15 E .18(cal bar \(\231)102 459.8 R .833<7c9a>.833 G 2.68(\)t)-.833 G
.179(he rest of the address is processed as a shell command.)156.456 459.8 R
.179(If the user name be)5.179 F .179(gins with a)-.15 F(slash mark \(\231/)102
471.8 Q(\232\) the name is used as a \214le name, instead of a login name.).833
E F0 2.5(3.3. Aliasing,)87 495.8 R -.25(Fo)2.5 G(rwarding, Inclusion).25 E F2
(Sendmail)127 512 Q F1 1.074(reroutes mail three w)3.574 F 3.574(ays. Aliasing)
-.1 F 1.075(applies system wide.)3.575 F -.15(Fo)6.075 G(rw).15 E 1.075
(arding allo)-.1 F 1.075(ws each)-.25 F .233
(user to reroute incoming mail destined for that account.)102 524 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)102 536 S
(ist of addresses, and is normally used in conjunction with aliasing.)111.72
536 Q F0 2.5(3.3.1. Aliasing)102 560 R F1 .065
(Aliasing maps local addresses to address lists using a system-wide \214le.)142
576.2 R .065(This \214le is hashed)5.065 F 1.546(to speed access.)117 588.2 R
1.545(Only addresses that parse as local are allo)6.546 F 1.545
(wed as aliases; this guarantees a)-.25 F(unique k)117 600.2 Q .3 -.15(ey \()
-.1 H(since there are no nicknames for the local host\).).15 E F0 2.5(3.3.2. F)
102 624.2 R(orwarding)-.25 E F1 .641
(After aliasing, if an recipient address speci\214es a local user)142 640.4 R
F2(sendmail)3.141 E F1 .641(searches for a \231.for)3.141 F(-)-.2 E -.1(wa)117
652.4 S .413(rd\232 \214le in the recipient').1 F 2.913(sh)-.55 G .413
(ome directory)235.335 652.4 R 5.413(.I)-.65 G 2.913(fi)302.161 652.4 S 2.913
(te)311.184 652.4 S .413(xists, the message is)321.167 652.4 R F2(not)2.913 E
F1 .412(sent to that user)2.913 F 2.912(,b)-.4 G(ut)496.22 652.4 Q .745
(rather to the list of addresses in that \214le.)117 664.4 R .746
(Often this list will contain only one address, and the)5.746 F
(feature will be used for netw)117 676.4 Q(ork mail forw)-.1 E(arding.)-.1 E
.32 LW 76 686 72 686 DL 80 686 76 686 DL 84 686 80 686 DL 88 686 84 686 DL 92
686 88 686 DL 96 686 92 686 DL 100 686 96 686 DL 104 686 100 686 DL 108 686 104
686 DL 112 686 108 686 DL 116 686 112 686 DL 120 686 116 686 DL 124 686 120 686
DL 128 686 124 686 DL 132 686 128 686 DL 136 686 132 686 DL 140 686 136 686 DL
144 686 140 686 DL 148 686 144 686 DL 152 686 148 686 DL 156 686 152 686 DL 160
686 156 686 DL 164 686 160 686 DL 168 686 164 686 DL 172 686 168 686 DL 176 686
172 686 DL 180 686 176 686 DL 184 686 180 686 DL 188 686 184 686 DL 192 686 188
686 DL 196 686 192 686 DL 200 686 196 686 DL 204 686 200 686 DL 208 686 204 686
DL 212 686 208 686 DL 216 686 212 686 DL/F4 5/Times-Roman@0 SF(2)93.6 696.4 Q
/F5 8/Times-Roman@0 SF(Disclaimer: Some special processing is done after re)3.2
I(writing local names; see belo)-.2 E -.52(w.)-.2 G F0 -1(Ve)72 756 S
(rsion 8.2)1 E(USENIX \255 J)249.805 756 Q(an 83)-.15 E(Last Mod 11/27/93)
424.55 756 Q EP
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/F0 10/Times-Bold@0 SF(Mail Systems and Addr)72 60 Q(essing in 4.2bsd)-.18 E(6)
499 60 Q/F1 10/Times-Roman@0 SF -.15(Fo)142 96 S(rw).15 E 1.152
(arding also permits a user to specify a pri)-.1 F -.25(va)-.25 G 1.151
(te incoming mailer).25 F 6.151(.F)-.55 G 1.151(or e)437.348 96 R 1.151
(xample, for)-.15 F(-)-.2 E -.1(wa)117 108 S(rding to:).1 E -2.5 .833("| /)157
124.2 T(usr/local/ne)-.833 E(wmail myname")-.25 E(will use a dif)117 140.4 Q
(ferent incoming mailer)-.25 E(.)-.55 E F0 2.5(3.3.3. Inclusion)102 164.4 R F1
(Inclusion is speci\214ed in RFC 733 [Crock)142 180.6 Q(er77] syntax:)-.1 E
(:Include: pathname)157 196.8 Q .391
(An address of this form reads the \214le speci\214ed by)117 213 R/F2 10
/Times-Italic@0 SF(pathname)2.891 E F1 .391
(and sends to all users listed in that)2.891 F(\214le.)117 225 Q .645
(The intent is)142 241.2 R F2(not)3.145 E F1 .644
(to support direct use of this feature, b)3.145 F .644
(ut rather to use this as a subset of)-.2 F 2.5(aliasing. F)117 253.2 R(or e)
-.15 E(xample, an alias of the form:)-.15 E
(project: :include:/usr/project/userlist)157 269.4 Q 1.93(is a method of letti\
ng a project maintain a mailing list without interaction with the system)117
285.6 R(administration, e)117 297.6 Q -.15(ve)-.25 G 2.5(ni).15 G 2.5(ft)203.54
297.6 S(he alias \214le is protected.)212.15 297.6 Q 2.025
(It is not necessary to reb)142 313.8 R 2.025(uild the inde)-.2 F 4.524(xo)-.15
G 4.524(nt)317.828 313.8 S 2.024(he alias database when a :include: list is)
330.132 313.8 R(changed.)117 325.8 Q F0 2.5(3.4. Message)87 349.8 R(Collection)
2.5 E F1 .857(Once all recipient addresses are parsed and v)127 366 R .857
(eri\214ed, the message is collected.)-.15 F .857(The message)5.857 F .574
(comes in tw)102 378 R 3.074(op)-.1 G .574
(arts: a message header and a message body)164.452 378 R 3.074(,s)-.65 G .574
(eparated by a blank line.)349.734 378 R .573(The body is)5.574 F
(an uninterpreted sequence of te)102 390 Q(xt lines.)-.15 E
(The header is formated as a series of lines of the form)127 406.2 Q
(\214eld-name: \214eld-v)178 422.4 Q(alue)-.25 E(Field-v)102 438.6 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)486.78 438.6 Q .211
(header \214elds ha)102 450.6 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.)102 462.6 Q
(Some header \214elds may be added automatically)5 E 2.5(,s)-.65 G
(uch as time stamps.)413.53 462.6 Q F0 2.5(4. THE)72 486.6 R(UUCP PR)2.5 E
(OBLEM)-.3 E F1 .43(Of particular interest is the UUCP netw)112 502.8 R 2.93
(ork. The)-.1 F -.15(ex)2.93 G .43(plicit routing used in the UUCP en).15 F
(vironment)-.4 E .909(causes a number of serious problems.)87 514.8 R .909
(First, gi)5.909 F .908(ving out an address is impossible without kno)-.25 F
.908(wing the)-.25 F .453(address of your potential correspondent.)87 526.8 R
.454(This is typically handled by specifying the address relati)5.453 F .754
-.15(ve t)-.25 H(o).15 E 1.208(some \231well-kno)87 538.8 R 1.208
(wn\232 host \(e.g., ucb)-.25 F -.25(va)-.15 G 3.708(xo).25 G 3.708(rd)253.47
538.8 S(ecv)265.508 538.8 Q 3.708(ax\). Second,)-.25 F 1.207(it is often dif)
3.708 F 1.207(\214cult to compute the set of)-.25 F .157
(addresses to reply to without some kno)87 550.8 R .157
(wledge of the topology of the netw)-.25 F 2.657(ork. Although)-.1 F .157
(it may be easy)2.657 F .352(for a human being to do this under man)87 562.8 R
2.851(yc)-.15 G .351(ircumstances, a program does not ha)259.713 562.8 R .651
-.15(ve e)-.2 H .351(qually sophisticated).15 F 1.153(heuristics b)87 574.8 R
1.153(uilt in.)-.2 F 1.154(Third, certain addresses will become painfully and \
unnecessarily long, as when a)6.153 F .406(message is routed through man)87
586.8 R 2.906(yh)-.15 G .406(osts in the USENET)225.81 586.8 R 5.406(.A)-.74 G
.406(nd \214nally)322.804 586.8 R 2.905(,c)-.65 G .405(ertain \231mix)370.465
586.8 R .405(ed domain\232 addresses)-.15 F
(are impossible to parse unambiguously \212 e.g.,)87 598.8 Q(decv)127 615 Q
(ax!ucb)-.25 E -.25(va)-.15 G(x!lbl-h!user@LBL-CSAM).25 E .378(might ha)87
631.2 R .678 -.15(ve m)-.2 H(an).15 E 2.878(yp)-.15 G .379
(ossible resolutions, depending on whether the message w)164.574 631.2 R .379
(as \214rst routed to decv)-.1 F .379(ax or)-.25 F(to LBL-CSAM.)87 643.2 Q 2.32
-.8(To s)112 659.4 T(olv).8 E 3.22(et)-.15 G .72
(his problem, the UUCP syntax w)152.49 659.4 R .719(ould ha)-.1 F 1.019 -.15
(ve t)-.2 H 3.219(ob).15 G 3.219(ec)346.956 659.4 S .719
(hanged to use addresses rather than)359.055 659.4 R 3.718(routes. F)87 671.4 R
1.218(or e)-.15 F 1.218(xample, the address \231decv)-.15 F(ax!ucb)-.25 E -.25
(va)-.15 G 1.218(x!eric\232 might be e).25 F 1.218(xpressed as \231eric@ucb)
-.15 F -.25(va)-.15 G(x.UUCP\232).25 E .079(\(with the hop through decv)87
683.4 R .079(ax implied\).)-.25 F .079(This address w)5.079 F .078
(ould itself be a domain-based address; for e)-.1 F(xam-)-.15 E
(ple, an address might be of the form:)87 695.4 Q([e-mail])127
711.6 Q F0 -1(Ve)72 756 S(rsion 8.2)1 E(USENIX \255 J)249.805 756 Q(an 83)-.15
E(Last Mod 11/27/93)424.55 756 Q EP
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