============================================================================== RED CIENTIFICA PERUANA ============================================================================== =-=-=-=-=-=-=-=-=-=-= =-=-=-=-=-=-=-=-=-=-= =-=-=-=-=-=-=-=-=-=-= Serving PCs and Workstations Using a Central Mail Server on an Internet ------- --- --- ------------ ----- - ------- ---- ------ -- -- -------- There are advantages to collecting mail destined to PCs and workstations on a central server, to be turned over to the PC or workstation on demand: - Your PC or workstation may be down quite a bit and less network bandwidth and less of the processing resouces of the sending computer are used if the computer receiving your mail is ready. - Some people use more than one PC or workstation to read mail. - A PC or workstation may not have the resources to store all the mail you receive. - It can make your e-mail address more like other users'. The easiest way to "implement" this is to run the central mail server like any multi-user system: let people sign on to it and use some mail utility. Then PC and workstation users can use "terminal sessions" to sign on to the central mail server and read their mail. This has the disadvantage of making the PC and workstation users learn and use the central mail server's procedures. SMTP, the "internet" mail protocol used to deliver mail between multi-user systems only supports mail transfer initiated by the sender. Other protocols have been devised to allow a workstation or PC to request transfer of mail, thus able to make use of a cnetral server. These include the published protocols POP (probably not used anymore), POP2, POP3, IMAP2, IMAP3 and DMSP. POP, POP2, POP3: These are rather minimal and are designed to be so. The three are similar but not enough alike to be interoperable. They are basically designed to identify the user by username and password, to transfer the mail from server to PC or workstation and to delete the mail transferred. It is assumed that SMTP will be used to send mail. Messages can be retrieved individually, but the only information you can get about a message without transferring it is its length in bytes-- useful for PCs with limited storage. POP2 and POP3 are still used a good deal. POP3 has a couple of optional extensions: one to avoid sending passwords, and one to aid in reading bulletin boards. IMAP2, IMAP3: The IMAP family is similar to the POP family, but also gives clients a way to do string searches through mail that still resides on the server. This is designed to allow the PC or workstation to be more selective as to which mail will be transferred. The POP protocols, on the other hand, are designed for simpler server software. IMAP2 is used quite a bit. IMAP3 is an incompatible offshoot that has not been implemented much. Recent work not yet documented in an RFC has extended IMAP2 to include support for multimedia mail. DMSP (aka PCMAIL): PCs and workstations can use this protocol to both send and receive mail. The system is designed around the idea that each user can own more than one workstation; however, the system doesn't seem to handle the idea of a "public workstation" very well. The PCs and workstations are assumed to hold state information about the mail, a directory so to speak, and when the PC or workstation is connected to the server, this directory is updated to "reality". More about the protocols: Name: Post Office Protocol, Version 2 Nickname: POP2 Document: RFC 937 (Butler et al, February 1985) TCP-port: 109 Sites: Name: Post Office Portocol, Version 3 Nickname: POP3 Document: RFC 1225 (Rose, May 1991) TCP-port: 110 (109 also often used) Sites: UC Irvine, MIT Name: Distributed Mail Service Protocol Nickname: DMSP, Pcmail Document: RFC 1056 (Lambert, June 1988) TCP-port: 158 Sites: MIT Name: Interactive Mail Access Protocol, Version 2 Nickname: IMAP2 Document: RFC 1176 (Crispin, August 1990) TCP-port: 143 Sites: Stanford, U Washington Name: Interactive Mail Access Protocol, Version 3 Nickname: IMAP3 Document: RFC 1203 (Rice, February 1991) TCP-port: 220 Sites: Stanford Implementations: Prot Computer Implementation End Source ------ ----------- ------------------- ------- -------------------------------- DSMP PC pc-epsilon (3.1) client allspice.lcs.mit.edu DSMP PC pc-netmail (3.1) client allspice.lcs.mit.edu DSMP PC pc-reader client allspice.lcs.mit.edu DSMP Unix Pcmail 3.1 reposit. server allspice.lcs.mit.edu DSMP Unix/EMACS Pcmail 4.2 client allspice.lcs.mit.edu DSMP PC PC/TCP client FTP Software DSMP OS/2 PC/TCP client FTP Software DSMP OS/2 TCP/2 client Essex Systems DSMP OS/2 TCP/2 SERVER PACK server Essex Systems DSMP OS/2 TCP/2 ADV CLIENT client Essex Systems IMAP2 Macintosh MacMS 2.2.1 client sumex-aim.stanford.edu IMAP2 Macintosh Mailstrom (beta) client sumex-aim.stanford.edu POP2 Macintosh MacPOP 1.5 client trident.arc.nasa.gov POP2 MS-DOS PC POP 2.1 client trident.arc.nasa.gov POP3 Macintosh TCP/Connect II client InterCon Systems Corporation IMAP2 NeXT EasyMail client ftp.cac.washington.edu IMAP2 NeXT MailManager server ftp.cac.washington.edu IMAP2 TOPS20 ? server ? IMAP2 Unix ? client ftp.cac.washington.edu IMAP2 Unix imapd 3.1 server sumex-aim.stanford.edu* IMAP2 Unix/X ximap 0.7.2 client sumex-aim.stanford.edu IMAP2 Unix imapd server ftp.cac.washington.edu IMAP2 Unix pine client ftp.cac.washington.edu IMAP2 Xrx Lsp Mch ? client ? IMAP2 MS-DOS pine (future) client ? IMAP2 MS-Windows ? client ?Some company in Canada POP2 Macintosh POPMail II client boombox.micro.umn.edu POP2 Macintosh MailStop server boombox.micro.umn.edu POP2 MS-DOS LifeLine Mail client SunSelect POP2 MS-DOS ka9q server ucsd.edu POP2 MS-DOS MD/DOS-IP client U Maryland POP2 MS-DOS PC/TCP client FTP Software POP2 Unix ? server boombox.micro.umn.edu POP2 Unix popd (USC-ISI) server trident.arc.nasa.gov POP2 Unix imapd/ipop2d server ftp.cac.washington.edu POP2 Unix mh-6.7 (UCI RandMH) server ftp.cc.berkeley.edu POP2 VM FAL server IBM POP2 VM ? server Texas Tech University POP2 OS/2 TCP/2 SERVER PACK server Essex Systems POP2 VMS MULTINet server TGV, Inc. POP3 Macintosh Eudora 1.2.2 client ftp.cso.uiuc.edu POP3 Macintosh Eudora 1.3 (in dev) client Not Yet POP3k Macintosh Eudora X client run at Brown U. POP3 Macintosh MacPOP (Berkeley) client ftp.cc.berkeley.edu POP3k Macintosh TechMail 2.0 client net-dist.mit.edu POP3 Macintosh MacMH client jessica.stanford.edu/info POP3 Macintosh POPMail II client boombox.micro.umn.edu POP3 Macintosh MailStop (soon) server UMinn POP3t Unix popper-1.7 server ftp.cc.berkeley.edu POP3 Unix popper-1.831 server ? POP3 Unix mh-6.7 (UCI RandMH) both ics.uci.edu POP3 Unix imapd/ipop3d server ftp.cac.washington.edu POP3t MS-DOS PC/TCP client FTP Software POP3 MS-DOS TechMail(future) client ? POP3 MS-DOS ? client logos.ucs.indiana.edu POP3 MS-DOS NUPOP (in beta) client (ftp.acns.nwu.edu) POP3 MS-DOS POPMail/PC client boombox.micro.umn.edu POP3 MS-DOS Eudora (alpha) client Qualcomm Inc (pc-eudora-info@qualcom.com) POP3 MS-DOS ka9q (future) server ? POP3 ? POPgate (Pmail gw) server risc.ua.edu POP3x MSwindows WinQVT (2.1) client QPC Software (shareware) POP3 MSwindows Eudora (future) client Qualcomm Inc (pc-eudora-info@qualcom.com) POP3 MSwindows wnqvtnet client ftp.cica.indiana.edu POP3 VMS IUPOP3 (1.7) (1.6?) server mythos.ucs.indiana.edu, logos? POP3 VMS MULTINet both TGV, Inc. POP3 OS/2 TCP/2 SERVER PACK server Essex Systems POP3 OS/2 TCP/2 ADV CLIENT client Essex Systems POP? MS-DOS UCDmail client ucdavis.ucdavis.edu POP? MS-DOS PC POP client ?Bill Schweickert/Sterling Fed POP? Macintosh MEWS client ? POP? Macintosh byupopmail client ? POP? VM ? server TTUVM1 ? Macintosh Hypermail ? ? ------ ----------- ------------------- ------- -------------------------------- Appendix: Some other packages for desktop systems ------ ----------- ------------------- ------- -------------------------------- uucp Macintosh uAccess peer ICE Engineering SMTP Macintosh LeeMail 1.2.4 peer Shareware, laf@mitre.org uucp Macintosh FernMail peer Shareware, dplatt@snulbug.mtview.ca.us prop Macintosh MacPost both ftp.lu.se uucp Macintosh Eudora peer ftp.cso.uiuc.edu uucp Macintosh UUPC peer dplatt@snulbug.mtview.ca.us uucp Macintosh gnuucp peer jim@fpr.com ? MS-DOS Pmail 2.3 (R1) client splicer.cba.hawaii.edu ? MS-DOS Pmail 2.3 (R2)(fut) client ? MS-Windows Pmain/Windows (fut) client ? Macintosh Pmail/Mac 1.1 client splicer.cba.hawaii.edu ? Macintosh Pmail/Mac 2.0(beta) client risc.ua.edu ------ ----------- ------------------- ------- -------------------------------- Other issues: (1) What are the common extensions to POP3 and which clients/servers support them? POP3k - kerberos POP3x - ? POP3t - xtnd xmit facility--allows client to send mail through additional POP commands, thus allowing server to verify/log source of mail. ------ ----------- ------------------- ------- -------------------------------- ----- End Included Message ----- .