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-/questiondown/Agrave/Aacute/Acircumflex/Atilde/Adieresis/Aring/AE -/Ccedilla/Egrave/Eacute/Ecircumflex/Edieresis/Igrave/Iacute/Icircumflex -/Idieresis/Eth/Ntilde/Ograve/Oacute/Ocircumflex/Otilde/Odieresis -/multiply/Oslash/Ugrave/Uacute/Ucircumflex/Udieresis/Yacute/Thorn -/germandbls/agrave/aacute/acircumflex/atilde/adieresis/aring/ae/ccedilla -/egrave/eacute/ecircumflex/edieresis/igrave/iacute/icircumflex/idieresis -/eth/ntilde/ograve/oacute/ocircumflex/otilde/odieresis/divide/oslash -/ugrave/uacute/ucircumflex/udieresis/yacute/thorn/ydieresis]def -/Times-Bold@0 ENC0/Times-Bold RE/Times-Italic@0 ENC0/Times-Italic RE -/Times-Roman@0 ENC0/Times-Roman RE -%%EndProlog -%%Page: 1 1 -%%BeginPageSetup -BP -%%EndPageSetup -/F0 14/Times-Roman@0 SF(Mail Systems and Addressing)204.196 141 Q -(in 4.2bsd)262.331 157.8 Q/F1 10/Times-Roman@0 SF(Eric Allman*)260.92 -181.8 Q/F2 10/Times-Italic@0 SF(Britton-Lee)254.86 199.8 Q 2.5(,I)-.1 G -(nc.)-2.5 E(1919 Addison Str)225.13 211.8 Q(eet, Suite 105.)-.37 E(Berk) -232.645 223.8 Q(ele)-.1 E 1.1 -.55(y, C)-.3 H(alifornia 94704.).55 E F1 -(eric@Berk)244.175 241.8 Q(ele)-.1 E -.65(y.)-.15 G(ARP).65 E(A)-.92 E -(ucb)264.6 253.8 Q -.25(va)-.15 G(x!eric).25 E(ABSTRA)262.085 286.2 Q -(CT)-.4 E .966 -(Routing mail through a heterogeneous internet presents man)112 302.4 R -3.466(yn)-.15 G 1.466 -.25(ew p)-3.466 H 3.466(roblems. Among).25 F .297 -(the w)112 314.4 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) --2.797 F(ad hoc basis.)112 326.4 Q(Ho)5 E(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 .099(Sendmail acts a uni\214ed \231post of)112 342.6 R -.098(\214ce\232 to which all mail can be submitted.)-.25 F .098 -(Address inter)5.098 F(-)-.2 E .754(pretation is controlled by a production system, which can parse both old and ne) -112 354.6 R 3.255(wf)-.25 G(or)-3.255 E(-)-.2 E .242(mat addresses.)112 -366.6 R .242(The ne)5.242 F 2.742(wf)-.25 G .242 -(ormat is \231domain-based,)-2.742 F 2.742<9a618d>-.7 G -.15(ex)-2.742 G -.241(ible technique that can handle).15 F(man)112 378.6 Q 2.606(yc)-.15 -G .106(ommon situations.)-2.606 F .106 -(Sendmail is not intended to perform user interf)5.106 F .107 -(ace functions.)-.1 F .399(Sendmail will replace deli)112 394.8 R -.15 -(ve)-.25 G .399(rmail in the Berk).15 F(ele)-.1 E 2.899(y4)-.15 G .399 -(.2 distrib)-2.899 F 2.899(ution. Se)-.2 F -.15(ve)-.25 G .399 -(ral major hosts).15 F .421(are no)112 406.8 R 2.921(wo)-.25 G 2.921(rw) --2.921 G .421(ill soon be running sendmail.)-2.921 F .421 -(This change will af)5.421 F .422(fect an)-.25 F 2.922(yu)-.15 G .422 -(sers that route)-2.922 F 1.5(mail through a sendmail g)112 418.8 R(ate) --.05 E -.1(wa)-.25 G 5.3 -.65(y. T).1 H 1.5 -(he changes that will be user visible are empha-).65 F(sized.)112 430.8 -Q .906 -(The mail system to appear in 4.2bsd will contain a number of changes.) -97 475.2 R .906(Most of these changes are)5.906 F .469 -(based on the replacement of)72 487.2 R F2(delivermail)2.969 E F1 .469 -(with a ne)2.969 F 2.969(wm)-.25 G .469(odule called)-2.969 F F2 2.97 -(sendmail. Sendmail)2.97 F F1 .47(implements a gen-)2.97 F 1.834 -(eral internetw)72 499.2 R 1.834(ork mail routing f)-.1 F(acility)-.1 E -4.333(,f)-.65 G 1.833(eaturing aliasing and forw)-4.333 F 1.833 -(arding, automatic routing to netw)-.1 F(ork)-.1 E -.05(ga)72 511.2 S -(te).05 E -.1(wa)-.25 G .205(ys, and \215e).1 F .205 -(xible con\214guration.)-.15 F .205(Of k)5.205 F .505 -.15(ey i)-.1 H -.205(nterest to the mail system user will be the changes in the net-).15 -F -.1(wo)72 523.2 S(rk addressing structure.).1 E .624(In a simple netw) -97 539.4 R .624(ork, each node has an address, and resources can be identi\214ed with a host-resource) --.1 F .374(pair; in particular)72 551.4 R 2.874(,t)-.4 G .374 -(he mail system can refer to users using a host-username pair)-2.874 F -5.374(.H)-.55 G .375(ost names and numbers)-5.374 F(ha)72 563.4 Q .3 --.15(ve t)-.2 H 2.5(ob).15 G 2.5(ea)-2.5 G -(dministered by a central authority)-2.5 E 2.5(,b)-.65 G -(ut usernames can be assigned locally to each host.)-2.7 E .397 -(In an internet, multiple netw)97 579.6 R .396(orks with dif)-.1 F .396 -(ferent characteristics and managements must communicate.)-.25 F .389 -(In particular)72 591.6 R 2.889(,t)-.4 G .389 -(he syntax and semantics of resource identi\214cation change.)-2.889 F -.39(Certain special cases can be han-)5.389 F 1.033(dled tri)72 603.6 R -1.033(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)72 615.6 Q -1.621(orks, as with the Ethernet at Xerox P)-.1 F 4.121(ARC. Ho)-.92 F -(we)-.25 E -.15(ve)-.25 G 2.421 -.4(r, t).15 H 1.622 -(he general case is e).4 F 1.622(xtremely comple)-.15 F 4.122(x. F)-.15 -F(or)-.15 E -.15(ex)72 627.6 S .29(ample, some netw).15 F .29 -(orks require that the route the message tak)-.1 F .29(es be e)-.1 F .29 -(xplicitly speci\214ed by the sender)-.15 F 2.79(,s)-.4 G(im-)-2.79 E -1.618(plifying the database update problem since only adjacent hosts must be entered into the system tables,) -72 639.6 R .573(while others use logical addressing, where the sender speci\214es the location of the recipient b) -72 651.6 R .573(ut not ho)-.2 F 3.072(wt)-.25 G(o)-3.072 E 1.065 -(get there.)72 663.6 R 1.065(Some netw)6.065 F 1.066 -(orks use a left-associati)-.1 F 1.366 -.15(ve s)-.25 H 1.066 -(yntax and others use a right-associati).15 F 1.366 -.15(ve s)-.25 H -1.066(yntax, causing).15 F .32 LW 76 673.2 72 673.2 DL 80 673.2 76 673.2 -DL 84 673.2 80 673.2 DL 88 673.2 84 673.2 DL 92 673.2 88 673.2 DL 96 -673.2 92 673.2 DL 100 673.2 96 673.2 DL 104 673.2 100 673.2 DL 108 673.2 -104 673.2 DL 112 673.2 108 673.2 DL 116 673.2 112 673.2 DL 120 673.2 116 -673.2 DL 124 673.2 120 673.2 DL 128 673.2 124 673.2 DL 132 673.2 128 -673.2 DL 136 673.2 132 673.2 DL 140 673.2 136 673.2 DL 144 673.2 140 -673.2 DL 148 673.2 144 673.2 DL 152 673.2 148 673.2 DL 156 673.2 152 -673.2 DL 160 673.2 156 673.2 DL 164 673.2 160 673.2 DL 168 673.2 164 -673.2 DL 172 673.2 168 673.2 DL 176 673.2 172 673.2 DL 180 673.2 176 -673.2 DL 184 673.2 180 673.2 DL 188 673.2 184 673.2 DL 192 673.2 188 -673.2 DL 196 673.2 192 673.2 DL 200 673.2 196 673.2 DL 204 673.2 200 -673.2 DL 208 673.2 204 673.2 DL 212 673.2 208 673.2 DL 216 673.2 212 -673.2 DL/F3 8/Times-Roman@0 SF .556(*A considerable part of this w)93.6 -685.2 R .556(ork w)-.08 F .556(as done while under the emplo)-.08 F -2.557(yo)-.08 G 2.557(ft)-2.557 G .557(he INGRES Project at the Uni) --2.557 F -.12(ve)-.2 G .557(rsity of California at).12 F(Berk)72 694.8 Q -(ele)-.08 E -.52(y.)-.12 G/F4 10/Times-Bold@0 SF(Mail Systems and Addr) -72 756 Q(essing in 4.2bsd)-.18 E(1)259.93 E EP -%%Page: 2 2 -%%BeginPageSetup -BP -%%EndPageSetup -/F0 10/Times-Bold@0 SF(Mail Systems and Addr)72 60 Q(essing in 4.2bsd) --.18 E(2)259.93 E/F1 10/Times-Roman@0 SF(ambiguity in mix)72 96 Q -(ed addresses.)-.15 E .679 -(Internet standards seek to eliminate these problems.)97 112.2 R -(Initially)5.678 E 3.178(,t)-.65 G .678(hese proposed e)-3.178 F .678 -(xpanding the address)-.15 F .331 -(pairs to address triples, consisting of {netw)72 124.2 R .331 -(ork, host, username} triples.)-.1 F(Netw)5.332 E .332 -(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 -136.2 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)-3.952 F(as)-.1 E .249(changed to address domains, comprised of a local resource identi\214cation and a hierarchical domain speci\214-) -72 148.2 R 1.54(cation with a common static root.)72 160.2 R 1.539 -(The domain technique separates the issue of ph)6.539 F 1.539(ysical v) --.05 F 1.539(ersus logical)-.15 F 3.001(addressing. F)72 172.2 R .501 -(or e)-.15 F .502(xample, an address of the form \231eric@a.cc.berk)-.15 -F(ele)-.1 E -.65(y.)-.15 G .502(arpa\232 describes the logical or).65 F --.05(ga)-.18 G(niza-).05 E .443(tion of the address space \(user \231eric\232 on host \231a\232 in the Computer Center at Berk) -72 184.2 R(ele)-.1 E .443(y\) b)-.15 F .443(ut not the ph)-.2 F(ysical) --.05 E(netw)72 196.2 Q .934(orks used \(for e)-.1 F .934 -(xample, this could go o)-.15 F -.15(ve)-.15 G 3.434(rd).15 G(if)-3.434 -E .934(ferent netw)-.25 F .935 -(orks depending on whether \231a\232 were on an)-.1 F -(ethernet or a store-and-forw)72 208.2 Q(ard netw)-.1 E(ork\).)-.1 E/F2 -10/Times-Italic@0 SF(Sendmail)97 224.4 Q F1 .493 -(is intended to help bridge the g)2.993 F .493(ap between the totally) --.05 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 .854 -(nothing of each other and the clean, tightly-coupled w)72 236.4 R .854 -(orld of unique netw)-.1 F .855(ork numbers.)-.1 F .855 -(It can accept old)5.855 F .633(arbitrary address syntax)72 248.4 R .632 -(es, resolving ambiguities using heuristics speci\214ed by the system administrator) --.15 F 3.132(,a)-.4 G(s)-3.132 E .347(well as domain-based addressing.) -72 260.4 R .347(It helps guide the con)5.347 F -.15(ve)-.4 G .347 -(rsion of message formats between disparate net-).15 F -.1(wo)72 272.4 S -3.395(rks. In).1 F(short,)3.395 E F2(sendmail)3.395 E F1 .894 -(is designed to assist a graceful transition to consistent internetw) -3.395 F .894(ork addressing)-.1 F(schemes.)72 284.4 Q .689 -(Section 1 de\214nes some of the terms frequently left fuzzy when w)97 -312.6 R .69(orking in mail systems.)-.1 F .69(Section 2)5.69 F .595 -(discusses the design goals for)72 324.6 R F2(sendmail)3.095 E F1 5.595 -(.I)C 3.095(ns)-5.595 G .595(ection 3, the ne)-3.095 F 3.095(wa)-.25 G -.594(ddress formats and basic features of)-3.095 F F2(send-)3.094 E -(mail)72 336.6 Q F1 .893(are described.)3.393 F .893 -(Section 4 discusses some of the special problems of the UUCP netw)5.893 -F 3.394(ork. The)-.1 F(dif)3.394 E(fer)-.25 E(-)-.2 E(ences between)72 -348.6 Q F2(sendmail)2.5 E F1(and)2.5 E F2(delivermail)2.5 E F1 -(are presented in section 5.)2.5 E F0(DISCLAIMER:)112 376.8 Q F1 3.333 -(An)3.333 G .833(umber of e)-3.333 F .832 -(xamples in this paper use names of actual people and)-.15 F(or)112 -388.8 Q -.05(ga)-.18 G 4.572(nizations. This).05 F 2.072 -(is not intended to imply a commitment or e)4.572 F -.15(ve)-.25 G 4.573 -(na).15 G 4.573(ni)-4.573 G(ntellectual)-4.573 E 1.094 -(agreement on the part of these people or or)112 400.8 R -.05(ga)-.18 G -3.594(nizations. In).05 F(particular)3.594 E 3.594(,B)-.4 G 1.094(ell T) --3.594 F(elephone)-.7 E .656 -(Laboratories \(BTL\), Digital Equipment Corporation \(DEC\), La)112 -412.8 R .657(wrence Berk)-.15 F(ele)-.1 E 3.157(yL)-.15 G(abo-)-3.157 E -2.136(ratories \(LBL\), Britton-Lee Incorporated \(BLI\), and the Uni) -112 424.8 R -.15(ve)-.25 G 2.136(rsity of California at).15 F(Berk)112 -436.8 Q(ele)-.1 E 3.088(ya)-.15 G .588(re not committed to an)-3.088 F -3.089(yo)-.15 G 3.089(ft)-3.089 G .589(hese proposals at this time.) --3.089 F .589(Much of this paper)5.589 F -(represents no more than the personal opinions of the author)112 448.8 Q -(.)-.55 E F0 2.5(1. DEFINITIONS)72 477 R F1 .266(There are four basic concepts that must be clearly distinguished when dealing with mail systems:) -112 493.2 R .514(the user \(or the user')87 505.2 R 3.014(sa)-.55 G .515 -(gent\), the user')-3.014 F 3.015(si)-.55 G .515 -(denti\214cation, the user')-3.015 F 3.015(sa)-.55 G .515 -(ddress, and the route.)-3.015 F .515(These are dis-)5.515 F -(tinguished primarily by their position independence.)87 517.2 Q F0 2.5 -(1.1. User)87 541.2 R(and Identi\214cation)2.5 E F1 .264(The user is the being \(a person or program\) that is creating or recei) -127 557.4 R .263(ving a message.)-.25 F(An)5.263 E F2 -.1(age)2.763 G -(nt).1 E F1 .659(is an entity operating on behalf of the user \212 such as a secretary who handles my mail.) -102 569.4 R .66(or a pro-)5.66 F(gram that automatically returns a message such as \231I am at the UNICOM conference.) -102 581.4 Q<9a>-.7 E .931(The identi\214cation is the tag that goes along with the particular user) -127 597.6 R 5.931(.T)-.55 G .931(his tag is completely)-5.931 F .216 -(independent of location.)102 609.6 R -.15(Fo)5.216 G 2.716(re).15 G -.216(xample, my identi\214cation is the string \231Eric Allman,)-2.866 F -2.717<9a61>-.7 G .217(nd this identi-)-2.717 F 1.228 -(\214cation does not change whether I am located at U.C. Berk)102 621.6 -R(ele)-.1 E 2.527 -.65(y, a)-.15 H 3.727(tB).65 G 1.227 -(ritton-Lee, or at a scienti\214c)-3.727 F(institute in Austria.)102 -633.6 Q 2.379(Since the identi\214cation is frequently ambiguous \(e.g., there are tw) -127 649.8 R 4.879<6f99>-.1 G 2.38(Robert Henry\232s at)-4.879 F(Berk)102 -661.8 Q(ele)-.1 E .316(y\) it is common to add other disambiguating information that is not strictly part of the iden-) --.15 F(ti\214cation \(e.g., Robert \231Code Generator\232 Henry v)102 -673.8 Q(ersus Robert \231System Administrator\232 Henry\).)-.15 E F0 -1 -(Ve)72 756 S(rsion 8.2)1 E(USENIX \255 J)130.475 E(an 83)-.15 E -(Last Mod 11/27/1993)88.355 E EP -%%Page: 3 3 -%%BeginPageSetup -BP -%%EndPageSetup -/F0 10/Times-Bold@0 SF(Mail Systems and Addr)72 60 Q(essing in 4.2bsd) --.18 E(3)259.93 E 2.5(1.2. Addr)87 96 R(ess)-.18 E/F1 10/Times-Roman@0 -SF .785(The address speci\214es a location.)127 112.2 R .786(As I mo) -5.786 F 1.086 -.15(ve a)-.15 H .786(round, my address changes.).15 F --.15(Fo)5.786 G 3.286(re).15 G .786(xample, my)-3.436 F .749 -(address might change from \231eric@Berk)102 124.2 R(ele)-.1 E -.65(y.) --.15 G(ARP).65 E .749 -(A\232 to \231eric@bli.UUCP\232 or \231allman@IIASA.Aus-)-.92 F -(tria\232 depending on my current af)102 136.2 Q(\214liation.)-.25 E(Ho) -127 152.4 Q(we)-.25 E -.15(ve)-.25 G 2.819 -.4(r, a).15 H 4.519(na).4 G -2.019(ddress is independent of the location of an)-4.519 F 2.019 -(yone else.)-.15 F 2.02(That is, my address)7.02 F .385 -(remains the same to e)102 164.4 R -.15(ve)-.25 G .385 -(ryone who might be sending me mail.).15 F -.15(Fo)5.385 G 2.885(re).15 -G .385(xample, a person at MIT and a)-3.035 F -(person at USC could both send to \231eric@Berk)102 176.4 Q(ele)-.1 E --.65(y.)-.15 G(ARP).65 E(A\232 and ha)-.92 E .3 -.15(ve i)-.2 H 2.5(ta) -.15 G(rri)-2.5 E .3 -.15(ve t)-.25 H 2.5(ot).15 G(he same mailbox.)-2.5 -E .627(Ideally a \231white pages\232 service w)127 192.6 R .627 -(ould be pro)-.1 F .627 -(vided to map user identi\214cations into addresses)-.15 F .444(\(for e) -102 204.6 R .444(xample, see [Solomon81]\).)-.15 F .444 -(Currently this is handled by passing around scraps of paper or by)5.444 -F(calling people on the telephone to \214nd out their address.)102 216.6 -Q F0 2.5(1.3. Route)87 240.6 R F1 .288(While an address speci\214es)127 -256.8 R/F2 10/Times-Italic@0 SF(wher)2.788 E(e)-.37 E F1 .289 -(to \214nd a mailbox, a route speci\214es)2.789 F F2(how)2.789 E F1 .289 -(to \214nd the mailbox.)2.789 F(Speci\214cally)102 268.8 Q 2.607(,i)-.65 -G 2.607(ts)-2.607 G .106(peci\214es a path from sender to recei)-2.607 F --.15(ve)-.25 G 3.706 -.55(r. A).15 H 2.606(ss).55 G .106 -(uch, the route is potentially dif)-2.606 F .106(ferent for)-.25 F -2.15 --.25(ev e)102 280.8 T(ry pair of people in the electronic uni).25 E -.15 -(ve)-.25 G(rse.).15 E .258 -(Normally the route is hidden from the user by the softw)127 297 R 2.758 -(are. Ho)-.1 F(we)-.25 E -.15(ve)-.25 G 1.058 -.4(r, s).15 H .258 -(ome netw).4 F .258(orks put the)-.1 F -.2(bu)102 309 S 1.972 -(rden of determining the route onto the sender).2 F 6.971(.A)-.55 G -1.971(lthough this simpli\214es the softw)-6.971 F 1.971(are, it also) --.1 F(greatly impairs the usability for most users.)102 321 Q -(The UUCP netw)5 E(ork is an e)-.1 E(xample of such a netw)-.15 E(ork.) --.1 E F0 2.5(2. DESIGN)72 345 R(GO)2.5 E(ALS)-.4 E F1(Design goals for) -112 363.2 Q F2(sendmail)2.5 E/F3 7/Times-Roman@0 SF(1)-4 I F1(include:) -2.5 4 M 12.5(\(1\) Compatibility)92 379.4 R 1.363(with the e)3.863 F -1.363(xisting mail programs, including Bell v)-.15 F 1.363 -(ersion 6 mail, Bell v)-.15 F 1.364(ersion 7)-.15 F 3.589(mail, Berk) -118.66 391.4 R(ele)-.1 E(y)-.15 E F2(Mail)6.089 E F1 3.589 -([Shoens79], BerkNet mail [Schmidt79], and hopefully UUCP mail)6.089 F -([No)118.66 403.4 Q 2.5(witz78]. ARP)-.25 F(ANET mail [Crock)-.92 E -(er82] w)-.1 E(as also required.)-.1 E 12.5(\(2\) Reliability)92 419.6 R -4.002(,i)-.65 G 4.002(nt)-4.002 G 1.502(he sense of guaranteeing that e) --4.002 F -.15(ve)-.25 G 1.502(ry message is correctly deli).15 F -.15 -(ve)-.25 G 1.503(red or at least).15 F .368(brought to the attention of a human for correct disposal; no message should e) -118.66 431.6 R -.15(ve)-.25 G 2.868(rb).15 G 2.868(ec)-2.868 G -(ompletely)-2.868 E 2.54(lost. This)118.66 443.6 R .04(goal w)2.54 F -.041(as considered essential because of the emphasis on mail in our en) --.1 F 2.541(vironment. It)-.4 F 1.755 -(has turned out to be one of the hardest goals to satisfy)118.66 455.6 R -4.254(,e)-.65 G 1.754(specially in the f)-4.254 F 1.754(ace of the man) --.1 F(y)-.15 E .977(anomalous message formats produced by v)118.66 467.6 -R .977(arious ARP)-.25 F .977(ANET sites.)-.92 F -.15(Fo)5.977 G 3.478 -(re).15 G .978(xample, certain sites)-3.628 F .069 -(generate improperly formated addresses, occasionally causing error) -118.66 479.6 R .069(-message loops.)-.2 F .068(Some hosts)5.069 F .766(use blanks in names, causing problems with mail programs that assume that an address is one) -118.66 491.6 R -.1(wo)118.66 503.6 S 3.924(rd. The).1 F 1.423 -(semantics of some \214elds are interpreted slightly dif)3.923 F 1.423 -(ferently by dif)-.25 F 1.423(ferent sites.)-.25 F(In)6.423 E(summary) -118.66 515.6 Q 3.022(,t)-.65 G .523(he obscure features of the ARP) --3.022 F .523(ANET mail protocol really)-.92 F F2(ar)3.023 E(e)-.37 E F1 -.523(used and are dif)3.023 F(\214cult)-.25 E(to support, b)118.66 527.6 -Q(ut must be supported.)-.2 E 12.5(\(3\) Existing)92 543.8 R(softw)2.939 -E .439(are to do actual deli)-.1 F -.15(ve)-.25 G .439 -(ry should be used whene).15 F -.15(ve)-.25 G 2.938(rp).15 G 2.938 -(ossible. This)-2.938 F .438(goal deri)2.938 F -.15(ve)-.25 G 2.938(sa) -.15 G(s)-2.938 E -(much from political and practical considerations as technical.)118.66 -555.8 Q 12.5(\(4\) Easy)92 572 R -.15(ex)2.898 G .398(pansion to f).15 F -.398(airly comple)-.1 F 2.898(xe)-.15 G -.4(nv)-2.898 G .399 -(ironments, including multiple connections to a single net-).4 F -.1(wo) -118.66 584 S .63(rk type \(such as with multiple UUCP or Ethernets\).).1 -F .63(This goal requires consideration of the)5.63 F(contents of an address as well as its syntax in order to determine which g) -118.66 596 Q(ate)-.05 E -.1(wa)-.25 G 2.5(yt).1 G 2.5(ou)-2.5 G(se.)-2.5 -E 12.5(\(5\) Con\214guration)92 612.2 R 1.048 -(information should not be compiled into the code.)3.548 F 3.549(As) -6.049 G 1.049(ingle compiled program)-3.549 F .084 -(should be able to run as is at an)118.66 624.2 R 2.584(ys)-.15 G .083 -(ite \(barring such basic changes as the CPU type or the operat-)-2.584 -F .342(ing system\).)118.66 636.2 R 1.942 -.8(We h)5.342 H -2.25 -.2 -(av e).8 H .343 -(found this seemingly unimportant goal to be critical in real life.) -3.042 F(Besides)5.343 E .734(the simple problems that occur when an) -118.66 648.2 R 3.234(yp)-.15 G .734(rogram gets recompiled in a dif) --3.234 F .733(ferent en)-.25 F(vironment,)-.4 E(man)118.66 660.2 Q 2.5 -(ys)-.15 G(ites lik)-2.5 E 2.5(et)-.1 G 2.5<6f99>-2.5 G -(\214ddle\232 with an)-2.5 E(ything that the)-.15 E 2.5(yw)-.15 G -(ill be recompiling an)-2.5 E(yw)-.15 E(ay)-.1 E(.)-.65 E .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(This section mak)3.2 I -(es no distinction between)-.08 E/F6 8/Times-Italic@0 SF(delivermail)2 E -F5(and)2 E F6(sendmail.)2 E F0 -1(Ve)72 756 S(rsion 8.2)1 E -(USENIX \255 J)130.475 E(an 83)-.15 E(Last Mod 11/27/1993)88.355 E EP -%%Page: 4 4 -%%BeginPageSetup -BP -%%EndPageSetup -/F0 10/Times-Bold@0 SF(Mail Systems and Addr)72 60 Q(essing in 4.2bsd) --.18 E(4)259.93 E/F1 10/Times-Roman@0 SF(\(6\))92 96 Q/F2 10 -/Times-Italic@0 SF(Sendmail)15 E 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) -118.66 108 Q(wn forw)-.25 E -(arding, without modifying the system alias \214le.)-.1 E 12.5 -(\(7\) Each)92 124.2 R .313 -(user should be able to specify which mailer to e)2.814 F -.15(xe)-.15 G -.313(cute to process mail being deli).15 F -.15(ve)-.25 G .313(red for) -.15 F 3.098(him. This)118.66 136.2 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)118.66 148.2 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 single 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)-2.991 F .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)-3.111 F(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\() -.1 G(as a comment\).)-2.5 E 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) --2.551 G .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)130.475 E(an 83)-.15 E(Last Mod 11/27/1993)88.355 E EP -%%Page: 5 5 -%%BeginPageSetup -BP -%%EndPageSetup -/F0 10/Times-Bold@0 SF(Mail Systems and Addr)72 60 Q(essing in 4.2bsd) --.18 E(5)259.93 E/F1 10/Times-Roman@0 SF(user name <machine-address>) -173.66 96 Q(will send to the electronic \231machine-address\232 rather than the human \231user name.) -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.)-2.5 F 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)-3.154 F -.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)-4 I F1(.)4 I .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. postal 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)-2.5 -E(ysical netw)-.05 E(ork.)-.1 E -.15(Fo)127 287 S 2.5(re).15 G -(xample, the address:)-2.65 E(eric@HostA.BigSite.ARP)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,)-3.975 E(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-) --3.109 F .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) --5.124 F .124(ariety of)-.25 F .69(situations, for e)102 407.6 R .691(xample, to maintain a public repository 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(ddress passing through the initial parsing algorithm as a local address \(i.e, not appear) --3.188 F(-)-.2 E .276(ing to be a v)102 447.8 R .276 -(alid address for another mailer\) is scanned for tw)-.25 F 2.776(os)-.1 -G .277(pecial cases.)-2.776 F .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.)-2.68 F .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.) --2.5 E 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)-2.913 F 5.413(.I)-.65 G 2.913(fi)-5.413 G -2.913(te)-2.913 G .413(xists, the message is)-3.063 F F2(not)2.913 E F1 -.412(sent to that user)2.913 F 2.912(,b)-.4 G(ut)-3.112 E .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)130.475 E(an 83)-.15 E(Last Mod 11/27/1993) -88.355 E EP -%%Page: 6 6 -%%BeginPageSetup -BP -%%EndPageSetup -/F0 10/Times-Bold@0 SF(Mail Systems and Addr)72 60 Q(essing in 4.2bsd) --.18 E(6)259.93 E/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)-6.301 F 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 letting 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)-2.5 G(he alias \214le is protected.)-2.5 E 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)-4.524 G 2.024 -(he alias database when a :include: list is)-4.524 F(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)-3.074 F 3.074(,s)-.65 G .574 -(eparated by a blank line.)-3.074 F .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)-6.366 E -.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.)-2.5 E 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 \(e.g., ucb)-.25 F -.25(va)-.15 G 3.708(xo).25 G 3.708(rd) --3.708 G(ecv)-3.708 E 3.708(ax\). 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) --2.851 F .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)-2.906 F 5.406(.A)-.74 G .406(nd \214nally) --5.406 F 2.905(,c)-.65 G .405(ertain \231mix)-2.905 F .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)-2.878 F .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)-3.22 F .719(ould ha)-.1 F 1.019 -.15 -(ve t)-.2 H 3.219(ob).15 G 3.219(ec)-3.219 G .719 -(hanged to use addresses rather than)-3.219 F 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(mark@d.cbosg.btl.UUCP) -127 711.6 Q F0 -1(Ve)72 756 S(rsion 8.2)1 E(USENIX \255 J)130.475 E -(an 83)-.15 E(Last Mod 11/27/1993)88.355 E EP -%%Page: 7 7 -%%BeginPageSetup -BP -%%EndPageSetup -/F0 10/Times-Bold@0 SF(Mail Systems and Addr)72 60 Q(essing in 4.2bsd) --.18 E(7)259.93 E/F1 10/Times-Roman@0 SF .311(Hosts outside of Bell T)87 -96 R .311(elephone Laboratories w)-.7 F .311(ould then only need to kno) --.1 F 2.811(wh)-.25 G .811 -.25(ow t)-2.811 H 2.811(og).25 G .312 -(et to a designated)-2.811 F(BTL relay)87 108 Q 2.5(,a)-.65 G -(nd the BTL topology w)-2.5 E(ould only be maintained inside Bell.)-.1 E -.543(There are three major problems associated with turning UUCP addresses into something reason-) -112 124.2 R .465(able: de\214ning the namespace, creating and propag)87 -136.2 R .465(ating the necessary softw)-.05 F .466(are, and b)-.1 F .466 -(uilding and main-)-.2 F(taining the database.)87 148.2 Q F0 2.5 -(4.1. De\214ning)87 172.2 R(the Namespace)2.5 E F1 1.015(Putting all UUCP hosts into a \215at namespace \(e.g., \231...@host.UUCP\232\) is not practical for a) -127 188.4 R .222(number of reasons.)102 200.4 R .222(First, with o)5.222 -F -.15(ve)-.15 G 2.722(r1).15 G .222(600 sites already)-2.722 F 2.722 -(,a)-.65 G .222(nd \(with the increasing a)-2.722 F -.25(va)-.2 G .222 -(ilability of ine).25 F(x-)-.15 E(pensi)102 212.4 Q 1.973 -.15(ve m)-.25 -H 1.673(icrocomputers and autodialers\) se).15 F -.15(ve)-.25 G 1.672 -(ral thousand more coming within a fe).15 F 4.172(wy)-.25 G 1.672 -(ears, the)-4.172 F .078(database update problem is simply intractable if the namespace is \215at.) -102 224.4 R .078(Second, there are almost cer)5.078 F(-)-.2 E 2.446 -(tainly name con\215icts today)102 236.4 R 7.446(.T)-.65 G 2.446 -(hird, as the number of sites gro)-7.446 F 4.946(wt)-.25 G 2.446 -(he names become e)-4.946 F -.15(ve)-.25 G 4.946(rl).15 G(ess)-4.946 E -(mnemonic.)102 248.4 Q .534(It seems ine)127 264.6 R .535(vitable that there be some sort of naming authority for the set of top le) --.25 F -.15(ve)-.25 G 3.035(ln).15 G(ames)-3.035 E .157 -(in the UUCP domain, as unpleasant a possibility as that may seem.)102 -276.6 R .157(It will simply not be possible to)5.157 F(ha)102 288.6 Q -.536 -.15(ve o)-.2 H .236(ne host resolving all names.).15 F .236 -(It may ho)5.236 F(we)-.25 E -.15(ve)-.25 G 2.736(rb).15 G 2.736(ep) --2.736 G .236(ossible to handle this in a f)-2.736 F .237 -(ashion similar to)-.1 F 1.582(that of assigning names of ne)102 300.6 R -1.582(wsgroups in USENET)-.25 F 6.582(.H)-.74 G -.25(ow)-6.582 G -2.15 --.25(ev e).25 H 2.382 -.4(r, i).25 H 4.082(tw).4 G 1.582 -(ill be essential to encourage)-4.082 F -2.15 -.25(ev e)102 312.6 T .52 -(ryone to become subdomains of an e).25 F .52(xisting domain whene)-.15 -F -.15(ve)-.25 G 3.02(rp).15 G .52(ossible \212 e)-3.02 F -.15(ve)-.25 G -3.02(nt).15 G .52(hough this will)-3.02 F .077(certainly bruise some e) -102 324.6 R 2.577(gos. F)-.15 F .077(or e)-.15 F .077(xample, if a ne) --.15 F 2.577(wh)-.25 G .076 -(ost named \231blid\232 were to be added to the UUCP)-2.577 F(netw)102 -336.6 Q .65(ork, it w)-.1 F .651(ould probably actually be addressed as \231d.bli.UUCP\232 \(i.e., as host \231d\232 in the pseudo-) --.1 F(domain \231bli\232 rather than as host \231blid\232 in the UUCP domain\).) -102 348.6 Q F0 2.5(4.2. Cr)87 372.6 R(eating and Pr)-.18 E -(opagating the Softwar)-.18 E(e)-.18 E F1 .078(The softw)127 388.8 R -.078(are required to implement a consistent namespace is relati)-.1 F --.15(ve)-.25 G .077(ly tri).15 F 2.577(vial. T)-.25 F .277 -.1(wo m)-.8 -H(odules).1 E(are needed, one to handle incoming mail and one to handle outgoing mail.) -102 400.8 Q 1.136 -(The incoming module must be prepared to handle either old or ne)127 417 -R 3.636(ws)-.25 G 1.136(tyle addresses.)-3.636 F(Ne)6.136 E(w-)-.25 E -.025(style addresses can be passed through unchanged.)102 429 R .024 -(Old style addresses must be turned into ne)5.025 F 2.524(ws)-.25 G -(tyle)-2.524 E(addresses where possible.)102 441 Q 2.247 -(The outgoing module is slightly trickier)127 457.2 R 7.247(.I)-.55 G -4.747(tm)-7.247 G 2.247(ust do a database lookup on the recipient)-4.747 -F .823(addresses \(passed on the command line\) to determine what hosts to send the message to.) -102 469.2 R .823(If those)5.823 F .023(hosts do not accept ne)102 481.2 -R .024(w-style addresses, it must transform all addresses in the header of the message) --.25 F(into old style using the database lookup.)102 493.2 Q 1.197 -(Both of these modules are straightforw)127 509.4 R 1.197(ard e)-.1 F -1.197(xcept for the issue of modifying the header)-.15 F 6.197(.I)-.55 G -(t)-6.197 E .944 -(seems prudent to choose one format for the message headers.)102 521.4 R --.15(Fo)5.944 G 3.444(ran).15 G .944(umber of reasons, Berk)-3.444 F -(ele)-.1 E(y)-.15 E .824(has elected to use the ARP)102 533.4 R .824 -(ANET protocols for message formats.)-.92 F(Ho)5.823 E(we)-.25 E -.15 -(ve)-.25 G 1.623 -.4(r, t).15 H .823(his protocol is some-).4 F -(what dif)102 545.4 Q(\214cult to parse.)-.25 E(Propag)127 561.6 Q 1.903 -(ation is some)-.05 F 1.903(what more dif)-.25 F 4.403(\214cult. There) --.25 F 1.903(are a lar)4.403 F 1.903(ge number of hosts connected to) --.18 F .812(UUCP that will w)102 573.6 R .811 -(ant to run completely standard systems \(for v)-.1 F .811 -(ery good reasons\).)-.15 F .811(The strate)5.811 F .811(gy is)-.15 F -(not to con)102 585.6 Q -.15(ve)-.4 G(rt the entire netw).15 E -(ork \212 only enough of it it alle)-.1 E(viate the problem.)-.25 E F0 -2.5(4.3. Building)87 609.6 R(and Maintaining the Database)2.5 E F1 .127 -(This is by f)127 625.8 R .127(ar the most dif)-.1 F .128 -(\214cult problem.)-.25 F 2.628(Ap)5.128 G .128 -(rototype for this database already e)-2.628 F .128(xists, b)-.15 F .128 -(ut it is)-.2 F(maintained by hand and does not pretend to be complete.) -102 637.8 Q .701(This problem will be reduced considerably if people choose to group their hosts into subdo-) -127 654 R 3.219(mains. This)102 666 R -.1(wo)3.219 G .719 -(uld require a global update only when a ne).1 F 3.22(wt)-.25 G .72 -(op le)-3.22 F -.15(ve)-.25 G 3.22(ld).15 G .72(omain joined the netw) --3.22 F(ork.)-.1 E 2.805(Am)102 678 S .305 -(essage to a host in a subdomain could simply be routed to a kno)-2.805 -F .304(wn domain g)-.25 F(ate)-.05 E -.1(wa)-.25 G 2.804(yf).1 G .304 -(or further)-2.804 F 3.073(processing. F)102 690 R .573(or e)-.15 F .573 -(xample, the address \231eric@a.bli.UUCP\232 might be routed to the \231bli\232 g) --.15 F(ate)-.05 E -.1(wa)-.25 G 3.074(yf).1 G(or)-3.074 E(redistrib)102 -702 Q 1.376(ution; ne)-.2 F 3.876(wh)-.25 G 1.375 -(osts could be added within BLI without notifying the rest of the w) --3.876 F 3.875(orld. Of)-.1 F(course, other hosts)102 714 Q/F2 10 -/Times-Italic@0 SF(could)2.5 E F1(be noti\214ed as an ef)2.5 E -(\214cienc)-.25 E 2.5(ym)-.15 G(easure.)-2.5 E F0 -1(Ve)72 756 S -(rsion 8.2)1 E(USENIX \255 J)130.475 E(an 83)-.15 E(Last Mod 11/27/1993) -88.355 E EP -%%Page: 8 8 -%%BeginPageSetup -BP -%%EndPageSetup -/F0 10/Times-Bold@0 SF(Mail Systems and Addr)72 60 Q(essing in 4.2bsd) --.18 E(8)259.93 E/F1 10/Times-Roman@0 SF .966 -(There may be more than one domain g)127 96 R(ate)-.05 E -.1(wa)-.25 G -4.767 -.65(y. A).1 H .967(domain such as BTL, for instance, might)4.117 -F(ha)102 108 Q .653 -.15(ve a d)-.2 H .353(ozen g).15 F(ate)-.05 E -.1 -(wa)-.25 G .353(ys to the outside w).1 F .352 -(orld; a non-BTL site could choose the closest g)-.1 F(ate)-.05 E -.1 -(wa)-.25 G 4.152 -.65(y. T).1 H(he).65 E .308(only restriction w)102 120 -R .308(ould be that all g)-.1 F(ate)-.05 E -.1(wa)-.25 G .308 -(ys maintain a consistent vie).1 F 2.808(wo)-.25 G 2.808(ft)-2.808 G -.308(he domain the)-2.808 F 2.808(yr)-.15 G(epresent.)-2.808 E F0 2.5 -(4.4. Logical)87 144 R(Structur)2.5 E(e)-.18 E F1(Logically)127 160.2 Q -3.803(,d)-.65 G 1.303(omains are or)-3.803 F -.05(ga)-.18 G 1.303 -(nized into a tree.).05 F 1.303 -(There need not be a host actually associated)6.303 F .462(with each le) -102 172.2 R -.15(ve)-.25 G 2.962(li).15 G 2.962(nt)-2.962 G .462 -(he tree \212 for e)-2.962 F .462 -(xample, there will be no host associated with the name \231UUCP)-.15 F --.7<2e9a>-1.11 G(Similarly)102 184.2 Q 3.115(,a)-.65 G 3.115(no)-3.115 G --2.19 -.18(rg a)-3.115 H .614 -(nization might group names together for administrati).18 F .914 -.15 -(ve r)-.25 H .614(easons; for e).15 F .614(xample, the)-.15 F(name)102 -196.2 Q(CAD.research.BigCorp.UUCP)142 212.4 Q(might not actually ha)102 -228.6 Q .3 -.15(ve a h)-.2 H(ost representing \231research.).15 E<9a>-.7 -E(Ho)127 244.8 Q(we)-.25 E -.15(ve)-.25 G 1.531 -.4(r, i).15 H 3.231(tm) -.4 G .731(ay frequently be con)-3.231 F -.15(ve)-.4 G .731(nient to ha) -.15 F 1.031 -.15(ve a h)-.2 H .732 -(ost or hosts that \231represent\232 a domain.).15 F -.15(Fo)102 256.8 S -3.466(re).15 G .966(xample, if a single host e)-3.616 F .966 -(xists that represents Berk)-.15 F(ele)-.1 E 2.266 -.65(y, t)-.15 H .966 -(hen mail from outside Berk).65 F(ele)-.1 E 3.466(yc)-.15 G(an)-3.466 E -(forw)102 268.8 Q .796 -(ard mail to that host for further resolution without kno)-.1 F .796 -(wing Berk)-.25 F(ele)-.1 E(y')-.15 E 3.296(s\()-.55 G .797(rather v) --3.296 F .797(olatile\) topol-)-.2 F(ogy)102 280.8 Q 5(.T)-.65 G -(his is not unlik)-5 E 2.5(et)-.1 G(he operation of the telephone netw) --2.5 E(ork.)-.1 E .053(This may also be useful inside certain lar)127 -297 R .053(ge domains.)-.18 F -.15(Fo)5.053 G 2.553(re).15 G .053 -(xample, at Berk)-2.703 F(ele)-.1 E 2.553(yi)-.15 G 2.553(tm)-2.553 G -.053(ay be pre-)-2.553 F .722(sumed that most hosts kno)102 309 R 3.222 -(wa)-.25 G .722(bout other hosts inside the Berk)-3.222 F(ele)-.1 E -3.223(yd)-.15 G 3.223(omain. But)-3.223 F .723(if the)3.223 F 3.223(yp) --.15 G .723(rocess an)-3.223 F .405(address that is unkno)102 321 R .405 -(wn, the)-.25 F 2.905(yc)-.15 G .405 -(an pass it \231upstairs\232 for further e)-2.905 F 2.905 -(xamination. Thus)-.15 F .405(as ne)2.905 F 2.905(wh)-.25 G .405 -(osts are)-2.905 F .488(added only one host \(the domain master\))102 -333 R/F2 10/Times-Italic@0 SF(must)2.989 E F1 .489 -(be updated immediately; other hosts can be updated)2.989 F(as con)102 -345 Q -.15(ve)-.4 G(nient.).15 E .583 -(Ideally this name resolution process w)127 361.2 R .583 -(ould be performed by a name serv)-.1 F .582(er \(e.g., [Su82b]\) to) --.15 F -.2(avo)102 373.2 S .507(id unnecessary cop).2 F .507 -(ying of the message.)-.1 F(Ho)5.507 E(we)-.25 E -.15(ve)-.25 G 1.307 --.4(r, i).15 H 3.007(nab).4 G .507(atch netw)-3.007 F .508 -(ork such as UUCP this could)-.1 F(result in unnecessary delays.)102 -385.2 Q F0 2.5(5. COMP)72 409.2 R(ARISON WITH DELIVERMAIL)-.74 E F2 -(Sendmail)112 425.4 Q F1(is an outgro)2.5 E(wth of)-.25 E F2 -(delivermail)2.5 E F1 5(.T)C(he primary dif)-5 E(ferences are:)-.25 E -12.5(\(1\) Con\214guration)92 441.6 R .573 -(information is not compiled in.)3.073 F .572 -(This change simpli\214es man)5.572 F 3.072(yo)-.15 G 3.072(ft)-3.072 G -.572(he problems of)-3.072 F(mo)118.66 453.6 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.)-2.5 E 12.5(\(2\) Address)92 469.8 R .491 -(parsing is more \215e)2.991 F 2.991(xible. F)-.15 F .491(or e)-.15 F -(xample,)-.15 E F2(delivermail)2.992 E F1 .492(only supported one g) -2.992 F(ate)-.05 E -.1(wa)-.25 G 2.992(yt).1 G 2.992(oa)-2.992 G -.15 -(ny)-2.992 G(netw)118.66 481.8 Q(ork, whereas)-.1 E F2(sendmail)2.5 E F1 -(can be sensiti)2.5 E .3 -.15(ve t)-.25 H 2.5(oh).15 G -(ost names and reroute to dif)-2.5 E(ferent g)-.25 E(ate)-.05 E -.1(wa) --.25 G(ys.).1 E 12.5(\(3\) F)92 498 R(orw)-.15 E 2.878(arding and :include: features eliminate the requirement that the system alias \214le be) --.1 F 1.073(writable by an)118.66 510 R 3.573(yu)-.15 G 1.073(ser \(or that an update program be written, or that the system administration) --3.573 F(mak)118.66 522 Q 2.5(ea)-.1 G(ll changes\).)-2.5 E(\(4\))92 -538.2 Q F2(Sendmail)15 E F1 .443(supports message batching across netw) -2.944 F .443(orks when a message is being sent to multiple)-.1 F -(recipients.)118.66 550.2 Q 12.5(\(5\) A)92 566.4 R 1.945 -(mail queue is pro)4.445 F 1.946(vided in)-.15 F F2(sendmail.)4.446 E F1 -1.946(Mail that cannot be deli)6.946 F -.15(ve)-.25 G 1.946 -(red immediately b).15 F 1.946(ut can)-.2 F .439(potentially be deli) -118.66 578.4 R -.15(ve)-.25 G .438 -(red later is stored in this queue for a later retry).15 F 5.438(.T)-.65 -G .438(he queue also pro)-5.438 F .438(vides a)-.15 F -.2(bu)118.66 -590.4 S -.25(ff).2 G .838(er ag).25 F .839(ainst system crashes; after the message has been collected it may be reliably redeli) --.05 F(v-)-.25 E(ered e)118.66 602.4 Q -.15(ve)-.25 G 2.5(ni).15 G 2.5 -(ft)-2.5 G(he system crashes during the initial deli)-2.5 E -.15(ve)-.25 -G(ry).15 E(.)-.65 E(\(6\))92 618.6 Q F2(Sendmail)15 E F1 1.351 -(uses the netw)3.851 F 1.351(orking support pro)-.1 F 1.351 -(vided by 4.2BSD to pro)-.15 F 1.35(vide a direct interf)-.15 F 1.35 -(ace net-)-.1 F -.1(wo)118.66 630.6 S .283(rks such as the ARP).1 F .284 -(ANET and/or Ethernet using SMTP \(the Simple Mail T)-.92 F .284 -(ransfer Protocol\))-.35 F -.15(ove)118.66 642.6 S 2.5(raT).15 G -(CP/IP connection.)-2.5 E F0 -1(Ve)72 756 S(rsion 8.2)1 E(USENIX \255 J) -130.475 E(an 83)-.15 E(Last Mod 11/27/1993)88.355 E EP -%%Page: 9 9 -%%BeginPageSetup -BP -%%EndPageSetup -/F0 10/Times-Roman@0 SF(REFERENCES)264.105 132 Q([Crock)87 148.2 Q 56.73 -(er77] Crock)-.1 F(er)-.1 E 3.535(,D)-.4 G 3.535(.H)-3.535 G 1.035(., V) --3.535 F 1.035(ittal, J. J., Pogran, K. T)-.6 F 1.035 -(., and Henderson, D. A. Jr)-.74 F(.,)-.55 E/F1 10/Times-Italic@0 SF -(Stan-)3.535 E(dar)195 160.2 Q 2.627(df)-.37 G .127(or the F)-2.627 F -.127(ormat of ARP)-1.05 F 2.627(AN)-.9 G .128(etwork T)-2.627 F -.2(ex) --.92 G 2.628(tM).2 G(essa)-2.628 E -.1(ge)-.1 G(s.).1 E F0 .128 -(RFC 733, NIC 41952.)5.128 F(In [Feinler78].)195 172.2 Q(No)5 E -.15(ve) --.15 G(mber 1977.).15 E([Crock)87 188.4 Q 56.73(er82] Crock)-.1 F(er)-.1 -E 4.272(,D)-.4 G 4.272(.H)-4.272 G(.,)-4.272 E F1(Standar)4.272 E 4.272 -(df)-.37 G 1.772(or the F)-4.272 F 1.772(ormat of Arpa Internet T)-1.05 -F -.2(ex)-.92 G 4.271(tM).2 G(essa)-4.271 E -.1(ge)-.1 G(s.).1 E F0 .025 -(RFC 822.)195 200.4 R(Netw)5.025 E .025(ork Information Center)-.1 F -2.526(,S)-.4 G .026(RI International, Menlo P)-2.526 F .026(ark, Cali-) --.15 F 2.5(fornia. August)195 212.4 R(1982.)2.5 E 60.51 -([Feinler78] Feinler)87 228.6 R 2.938(,E)-.4 G .438(., and Postel, J.) --2.938 F(\(eds.\),)5.438 E F1(ARP)2.938 E .438(ANET Pr)-.9 F .438 -(otocol Handbook.)-.45 F F0 .438(NIC 7104,)5.438 F(Netw)195 240.6 Q -3.011(ork Information Center)-.1 F 5.511(,S)-.4 G 3.012 -(RI International, Menlo P)-5.511 F 3.012(ark, California.)-.15 F(1978.) -195 252.6 Q([No)87 268.8 Q 59.65(witz78] No)-.25 F .479 -(witz, D. A., and Lesk, M. E.,)-.25 F F1 2.978(AD)2.978 G .478 -(ial-Up Network of UNIX Systems.)-2.978 F F0(Bell)5.478 E 3.528 -(Laboratories. In)195 280.8 R 1.029(UNIX Programmer')3.528 F 3.529(sM) --.55 G 1.029(anual, Se)-3.529 F -.15(ve)-.25 G 1.029(nth Edition, V).15 -F 1.029(olume 2.)-1.29 F(August, 1978.)195 292.8 Q 55.5 -([Schmidt79] Schmidt,)87 309 R(E.,)2.631 E F1 .131(An Intr)2.631 F .131 -(oduction to the Berk)-.45 F(ele)-.1 E 2.631(yN)-.3 G(etwork.)-2.631 E -F0(Uni)5.131 E -.15(ve)-.25 G .131(rsity of Califor).15 F(-)-.2 E -(nia, Berk)195 321 Q(ele)-.1 E 2.5(yC)-.15 G 2.5(alifornia. 1979.)-2.5 F -59.95([Shoens79] Shoens,)87 337.2 R(K.,)3.227 E F1 .728(Mail Refer)3.227 -F .728(ence Manual.)-.37 F F0(Uni)5.728 E -.15(ve)-.25 G .728 -(rsity of California, Berk).15 F(ele)-.1 E 4.528 -.65(y. I)-.15 H(n).65 -E 3.478(UNIX Programmer')195 349.2 R 5.977(sM)-.55 G 3.477(anual, Se) --5.977 F -.15(ve)-.25 G 3.477(nth Edition, V).15 F 3.477(olume 2C.)-1.29 -F(December)8.477 E(1979.)195 361.2 Q 52.72([Solomon81] Solomon,)87 377.4 -R .251(M., Landweber)2.75 F 2.751(,L)-.4 G .251(., and Neuhengen, D.,) --2.751 F F1 .251(The Design of the CSNET)2.751 F .397(Name Server)195 -389.4 R(.)-1.11 E F0 2.896(CS-DN-2. Uni)5.397 F -.15(ve)-.25 G .396 -(rsity of W).15 F .396(isconsin, Madison.)-.4 F .396(October 1981.)5.396 -F 73.84([Su82a] Su,)87 405.6 R(Za)2.844 E .344(w-Sing, and Postel, Jon,) --.15 F F1 .344(The Domain Naming Con)2.844 F .344(vention for Internet) --.4 F 2.71(User Applications.)195 417.6 R F0 5.21(RFC819. Netw)7.71 F -2.71(ork Information Center)-.1 F 5.21(,S)-.4 G 2.71(RI Interna-)-5.21 F -(tional, Menlo P)195 429.6 Q(ark, California.)-.15 E(August 1982.)5 E -73.28([Su82b] Su,)87 445.8 R(Za)4.174 E(w-Sing,)-.15 E F1 4.174(AD)4.174 -G(istrib)-4.174 E 1.675(uted System for Internet Name Service)-.2 F(.) --.15 E F0(RFC830.)6.675 E(Netw)195 457.8 Q 3.012(ork Information Center) --.1 F 5.512(,S)-.4 G 3.011(RI International, Menlo P)-5.512 F 3.011 -(ark, California.)-.15 F(October 1982.)195 469.8 Q/F2 10/Times-Bold@0 SF -(Mail Systems and Addr)72 756 Q(essing in 4.2bsd)-.18 E(9)259.93 E EP -%%Trailer -end -%%EOF |