Club LOGIN Le courrier électronique comment ça marche?

Transcription

1 Club LOGIN Le courrier électronique comment ça marche? Durée: 60 minutes Gregor Bruhin, avril

2 Objectifs Comprendre les principes de base et le fonctionnement du courrier électronique Se familiariser avec les protocoles impliqués Comprendre comment les mails sont acheminés vers les boîtes aux lettres Présentation des problèmes et difficultés qu'un provider internet peut rencontrer pour fournir ces services (si on a le temps) 2

3 Définitions Application client-serveur Protocoles réseau, TCP/IP DNS Serveurs, Services Interopérabilité 3

4 Structure d un Header Body MIME (Multipurpose Internet Mail Extensions) Multipart UUEncodé 8bit -> 7bit 4

5 Structure d un , exemple From ots. service@newsaktuell.ch Wed Apr 7 20:27: Return-Path: <ots. service@newsaktuell.ch> Received: from mx8.bluewin.ch ( ) by mssazhb-int.msg.bluewin.ch (Bluewin AG ) id 4057CA700191B9ED for gregor.bruhin@bluewin.ch; Wed, 7 Apr :39: Received: from mail.newsaktuell.ch ( ) by mx8.bluewin.ch (Bluewin AG ) id 4056CBB300B70A20; Wed, 7 Apr :39: Received: from chi.newsaktuell.ch ([ ]) by mail.newsaktuell.ch with esmtp (Exim 3.16 #1) id 1BBF7u-00053x-00; Wed, 07 Apr :38: Received: from root (helo=mail.newsaktuell.ch) by CHI.newsaktuell.ch with local-smtp (Exim 4.12) id 1BBF7u-0000JZ-00; Wed, 07 Apr :38: To: ots.economie.fr@newsaktuell.ch To: ots.sante.fr@newsaktuell.ch To: ots.politique.fr@newsaktuell.ch Errors-To: listerrors@newsaktuell.ch Reply-To: listadmin@newsaktuell.ch From: ots. service@newsaktuell.ch Subject: Le Conseil fédéral refuse une protection légale moderne à une... MIME-Version: 1.0 Content-Type: text/plain; charset=iso Content-Transfer-Encoding: 8bit Message-Id: <E1BBF7u-0000JZ-00@CHI.newsaktuell.ch> Date: Wed, 07 Apr :38: Le Conseil fédéral refuse une protection légale moderne à une grande partie du personnel hospitalier Berne (ots) - L'ASMAC déplore la décision prise par le Conseil fédéral. Une chance unique de faire bénéficier l'ensemble du personnel hospitalier d'une réglementation moderne en matière de protection des travailleurs vient d'être perdue. La décision du Conseil fédéral s'avère problématique du point de vue du droit du travail: fruit d'une logique difficile à suivre, elle favorise un traitement inégal des personnels hospitaliers, des hôpitaux et des cantons. 5

6 Fonctionnalités Envoyer (SMTP) Recevoir (POP) 6

7 7

8 SMTP Envoi de mails RFC 2821 Premiers services commerciaux 1988 ESMTP 250-sun3.netoxygen.ch Hello sun5.netoxygen.ch [ ] (may be forged), pleased to meet you 250-ENHANCEDSTATUSCODES 250-PIPELINING 250-8BITMIME 250-SIZE 250-DSN 250-ETRN 250-AUTH LOGIN PLAIN 250-STARTTLS 250-DELIVERBY 250 HELP 8

9 SMTP telnet mail.netoxygen.ch 25 Trying Connected to sun3.netoxygen.ch. Escape character is '^]'. 220 sun3.netoxygen.ch ESMTP Sendmail / ; Tue, 13 Apr :25: helo greg.club-login.ch 250 sun3.netoxygen.ch Hello greg.mcnet.ch [ ] (may be forged), pleased to meet you mail Sender ok rcpt Recipient ok data 354 Enter mail, end with "." on a line by itself from:blah@toto.ch to:president@whitehouse.gov subject:hello test i3dkpp1a Message accepted for delivery 9

10 Envoi SMTP (résultat) 10

11 POP3 Réception de mails RFC 1939 POP vs IMAP 11

12 POP3 telnet pop.netoxygen.ch 110 Trying Connected to sun3.netoxygen.ch. Escape character is '^]'. +OK mail.netoxygen.ch Cyrus POP3 v server ready user gregxxxxx +OK Name is a valid mailbox pass XXXXXXXX +OK Maildrop locked and ready list +OK scan listing follows retr 1 +OK Message follows Return-Path: <gbruhin@vianetworks.ch> Received: from sun3.netoxygen.ch ([unix socket]) by mail.netoxygen.ch (Cyrus v2.1.15) with LMTP; Tue, 13 Apr :27: X-Sieve: CMU Sieve 2.2 Received: from greg.club-login.ch (greg.mcnet.ch [ ] (may be forged)) by sun3.netoxygen.ch ( / ) with SMTP id i3dkpp1a for gregor.bruhin@netoxygen.ch; Tue, 13 Apr :26: Date: Tue, 13 Apr :25: Message-Id: < i3DKPp1a012147@sun3.netoxygen.ch> from: blah@toto.ch to: president@whitehouse.gov subject: hello - SPAM X-Spam-Score: (*****) BAYES_44,DATE_MISSING,MSGID_FROM_MTA_SHORT,NO_REAL_NAME,SUB_HELLO X-Spam-Status: YES X-Spam-Flag: YES X-Scanned-By: MIMEDefang 2.36 test. 12

13 Routage Validation, vérification des droits Lookups DNS (MX record) Relaying Enveloppe Le contenu n influence pas le routage Fiabilité Queueing 13

14 Côté ISP Répartition de charge Redondance / Fiabilité Filtrage spam/virus Obligations légales Postmaster@, abuse, 14

15 dig mx bluewin.ch ; <<>> DiG <<>> mx bluewin.ch ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: ;; flags: qr aa ra; QUERY: 1, ANSWER: 3, AUTHORITY: 4, ADDITIONAL: 6 ;; QUESTION SECTION: ;bluewin.ch. IN MX ;; ANSWER SECTION: bluewin.ch IN MX 30 mxzhb.bluewin.ch. bluewin.ch IN MX 10 mxbw.bluewin.ch. bluewin.ch IN MX 20 mxzhh.bluewin.ch. ;; AUTHORITY SECTION: bluewin.ch IN NS dns1.bluewin.ch. bluewin.ch IN NS dns2.bluewin.ch. bluewin.ch IN NS dns3.bluewin.ch. bluewin.ch IN NS dns4.bluewin.ch. ;; ADDITIONAL SECTION: mxzhh.bluewin.ch IN A mxzhb.bluewin.ch IN A dns1.bluewin.ch IN A dns2.bluewin.ch IN A dns3.bluewin.ch IN A dns4.bluewin.ch IN A

16 RFC s POP RFC 1939 RFC 1734 RFC 2449 RFC 2595 RFC 3206 Post Office Protocol - Version 3 (POP3) POP3 AUTHentication command POP3 Extension Mechanism Using TLS with IMAP, POP3 and ACAP The SYS and AUTH POP Response Codes SMTP RFC821 SMTP protocol RFC822 Mail header format RFC974 MX routing RFC1123 Host requirements (modifies 821, 822, and 974) RFC1344 Implications of MIME for Internet Mail Gateways RFC1413 Identification server RFC1428 Transition of Internet Mail from Just-Send-8 to 8-bit SMTP/MIME RFC1652 SMTP Service Extension for 8bit-MIMEtransport RFC1894 An Extensible Message Format for Delivery Status Notifications RFC1985 SMTP Service Extension for Remote Message Queue Starting RFC2034 SMTP Service Extension for Returning Enhanced Error Codes RFC2045 Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies RFC2476 Message Submission RFC2554 SMTP Service Extension for Authentication RFC2821 Simple Mail Transfer Protocol RFC2822 Internet Message Format RFC2852 Deliver By SMTP Service Extension RFC2920 SMTP Service Extension for Command Pipelining 16

17 Questions??? 17