This article was posted to the Usenet group alt.hackers in
1995; any technical information is probably outdated.
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Re: Mail systems on AOL
Article: 8411 of alt.hackers From: crosby@cs.colorado.edu Newsgroups: alt.hackers Subject: Re: Mail systems on AOL Date: 8 Aug 1995 13:26:15 GMT Organization: University of Colorado, Boulder Lines: 87 Approved: me Message-ID: 407oln$6ko@lace.Colorado.EDU NNTP-Posting-Host: taussky.cs.colorado.edu Status: RO
In article <405vfu$krm@senator-bedfellow.mit.edu>, Simon Joseph Dedeo <dedeo@mit.edu> wrote: >Having read the RFC's for SMTP, I've been led >to believe that sending mail is impossible unless >one can telnet to the SMTP port of the destination >site (usu. 25). How, then, does mail from aol.com >"escape"? Mail *seems* to be coming from something >like "emout04.mail.aol.com", but I'm unable to telnet >to port 25 there. What's up with that? Isn't the >ability to access that port necessary for two >machines to exchange message texts? > >And now I'm *really* getting out of my league... >When mail is addressed "jloser@aol.com", the mail >program must access the DNS to locate the address >to telnet to, right? So why does a telnet to aol.com >return a "No address associated with name" error? > >-Simon D. >apologies for the foolish statements in the paragraphs above. > Well, you are on the right track. Firstly, the machine originating the mail doesn't have to be able to receive mail. Thus, emout04 (as I suppose one could guess from the name) is probably just for sending mail only. Secondly, for sending mail, you are on the right track. The trick is in your statement about accessing DNS. Your next reading, therefore, should be about DNS, and in particular (hint) things called mx records. Double hint: ebola:crosby% dig mx aol.com ; <<>> DiG 2.0 <<>> mx aol.com ;; res options: init recurs defnam dnsrch ;; got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6 ;; flags: qr rd ra; Ques: 1, Ans: 5, Auth: 4, Addit: 9 ;; QUESTIONS: ;; aol.com, type = MX, class = IN ;; ANSWERS: aol.com. 26892 MX 15 emin04.mail.aol.com. aol.com. 26892 MX 15 emin05.mail.aol.com. aol.com. 26892 MX 15 mail03.mail.aol.com. aol.com. 26892 MX 15 emin06.mail.aol.com. aol.com. 26892 MX 15 mail05.mail.aol.com. ;; AUTHORITY RECORDS: aol.COM. 113292 NS HP81.PROD.AOL.NET. aol.COM. 113292 NS OPS01.OPS.aol.com. aol.COM. 113292 NS NIS.ANS.NET. aol.COM. 113292 NS NS.ANS.NET. ;; ADDITIONAL RECORDS: emin04.mail.aol.com. 44436 A 198.81.10.11 emin05.mail.aol.com. 44436 A 198.81.10.36 mail03.mail.aol.com. 36820 A 152.163.172.49 emin06.mail.aol.com. 20186 A 198.81.10.44 mail05.mail.aol.com. 44436 A 152.163.172.109 HP81.PROD.AOL.NET. 102162 A 192.203.190.18 OPS01.OPS.aol.com. 113292 A 152.163.80.11 NIS.ANS.NET. 306782 A 147.225.1.2 NS.ANS.NET. 306782 A 192.103.63.100 ;; Total query time: 46 msec ;; FROM: ebola.UU.NET to SERVER: default -- 153.39.240.10 ;; WHEN: Tue Aug 8 09:13:29 1995 ;; MSG SIZE sent: 25 rcvd: 390 Good luck! You are on the path to enlightenment, O grasshopper. ObHack: Writing a postscript pretty print program in Perl using only the output from MS write (blech) as a postscript reference. Not much of a hack, especially as I was once pretty good a postscript (Though I haven't programmed it in like two years and have forgotten everything...I need to buy a copy of the blue book), but it was all I could think of for the moment. I'll post of something better later.
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