Basic Internet Services e Mail login file transfer

Basic Internet Services e. Mail, login, file transfer, news, document distribution, Web services Service management www. infotech. monash. edu

e. Mail Active message delivery – “push” technology TCP Port: 25 uses Simple Mail Transfer Protocol (SMTP) Clients: • mailx, pegasus, MS Outlook, Netscape Messenger, Mozilla Thunderbird… Servers: • Sendmail (Unix), MS-Exchange, Netscape Messaging Server, Mailman, Maiser… www. infotech. monash. edu 2

Terminal Emulation • • • uses Telnet protocol TCP Port: 23 Clients: telnet Servers: telnetd (Unix) Now rarely used (for security reasons) www. infotech. monash. edu 3

Secure Terminal Emulation • • Secure Shell protocol (ssh) Uses TCP port 22 Handles session key negotiation and encryption of traffic Also possible to do encapsulation of data from other ports on client and server machines (port forwarding) • Client: ssh, putty, teraterm • Server: sshd (unix) www. infotech. monash. edu 4

File Transfer • • Uses File Transfer Protocol (FTP) Port: 21 Clients: ftp Servers: ftpd (Unix), embedded in IIS (Win 32) www. infotech. monash. edu 5

Secure File Transfer • Secure File Copy (scp) • Secure File Transfer Protocol (s. FTP) • Usually implemented as cp or ftp inside ssh encapsulated session • Clients: win. SCP (win 32), Fugu (Mac OS/X) • Servers: sshd (UNIX) www. infotech. monash. edu 6

News • • • Passive messaging - “pull technology” Uses Network News Transfer Protocol Port: 119 Clients: MS Outlook, Netscape Collabra, Mozilla Thunderbird Servers: nntpd(Unix), www. infotech. monash. edu 7

Web Services • Uses HTML for message format and HTTP for message transport • port: 80 (or 8080) or 445 for secure HTTP • Clients: Mozilla firefox, Netscape Navigator, MS Internet. Explorer, Opera • Servers: IIS (win 32), apache (unix & win 32), tinyhttpd www. infotech. monash. edu 8

Client/Server, 1 -to-Many With each of the preceding, multiple clients may communicate with a single server www. infotech. monash. edu

File Transfer Protocol (FTP) www. infotech. monash. edu 10

e. Mail • The normal usage of this application is to create a message for another user on a local or remote computer system and have it delivered electronically. • An example of “push” delivery www. infotech. monash. edu 11

e. Mail (cont’d) e. g. mail johnm@vax. ftp. com Subject: How is the Project? Message -----------------------Hi, I got your last message. . etc www. infotech. monash. edu 12

e. Mail (cont’d) The message is sent from the originating mail serving application to the destination mail serving application via a route that may pass through many mailservers on its way. MTA mailservers MTA Mail clients www. infotech. monash. edu 13

e. Mail -- SMTP Headers Received: from (2) ALPHA 8. MONASH. EDU. AU by (1) silas. monash. edu. au (8. 9. 3/1. 1. 29. 3/16 Feb 01 -1022 AM) id XAA 0000955685; Tue, 23 Apr 2002 23: 50: 56 +1000 (EST) Received: from blammo. monash. edu. au ([129. 179. 1. 74]) by (3) vaxh. monash. edu. au (PMDF V 5. 2 -31 #39306) with ESMTP id <01 KGX 6 J 1 JA 328 WW 4 SY@vaxh. monash. edu. au> for asad@silas. monash. edu. au; Tue, 23 Apr 2002 23: 50: 48 +1000 Received: from blammo (unknown [127. 0. 0. 1]) by (4) localhost (Postfix) with ESMTP id 5425712 C 002 for <asad@silas. monash. edu. au>; Tue, 23 Apr 2002 13: 50: 43 +0000 (/etc/localtime) Received: from mail 1. monash. edu. au (bigted. monash. edu. au [129. 179. 11. 60]) by (5) blammo. monash. edu. au (Postfix) with ESMTP id 14 A 8512 C 002 for <asad@silas. monash. edu. au>; Tue, 23 Apr 2002 23: 50: 43 +1000 (EST) Received: from ALPHA 1. MONASH. EDU. AU ([129. 179. 1. 1]) by (6) mail 1. monash. edu. au (Netscape Messaging Server 4. 15) with ESMTP id GV 0 X 4 I 00. NBA for <asad@mail 1. monash. edu>; Tue, 23 Apr 2002 23: 50: 42 +1000 www. infotech. monash. edu 14

e. Mail -- SMTP Headers Received: from (8) blammo. monash. edu. au ([129. 179. 1. 74]) by (7) vaxc. monash. edu. au (PMDF V 6. 1 #39306) with ESMTP id <01 KGX 6 IRZ 3 MQ 922 MOH@vaxc. monash. edu. au> for asad@mail 1. monash. edu (ORCPT asadkhan@inftech. monash. edu. au); Tue, 23 Apr 2002 23: 50: 31 +1000 Received: from blammo (unknown [127. 0. 0. 1]) by localhost (Postfix) with ESMTP id 762 F 512 C 002 for <asadkhan@inftech. monash. edu. au>; Tue, 23 Apr 2002 13: 50: 30 +0000 (/etc/localtime) Received: from (9) mail 021. syd. optusnet. com. au (mail 021. syd. optusnet. com. au [200. 39. 20. 161]) by blammo. monash. edu. au (Postfix) with ESMTP id 1 F 4 AE 12 C 002 for <asadkhan@inftech. monash. edu. au>; Tue, 23 Apr 2002 23: 50: 30 +1000 (EST) Received: from CO 3025549 A (10) (c 16494. frank 1. vic. optusnet. com. au [200. 39. 205. 113]) www. infotech. monash. edu 15

e. Mail -- SMTP Headers by mail 021. syd. optusnet. com. au (8. 11. 1/8. 11. 1) with SMTP id g 3 NDo. Ri 15920 for <asadkhan@infotech. monash. edu. au>; Tue, 23 Apr 2002 23: 50: 27 +1000 Date: Tue, 23 Apr 2002 23: 51: 34 +1000 From: Patrik <patrik@optushome. com> Subject: Questions To: asadkhan@infotech. monash. edu. au Message-id: <EFEOICAJMKDCOLDIMNJNCEBACAAA. patrik@optushome. com> MIME-version: 1. 0 X-MIMEOLE: Produced By Microsoft Mime. OLE V 6. 00. 2600. 0000 X-Mailer: Microsoft Outlook IMO, Build 9. 0. 2416 (9. 0. 2910. 0) Content-type: MULTIPART/MIXED; BOUNDARY="Boundary_(ID_DI+x. GCWXZl. Chun 9 D 5 NMJlw)" Importance: Normal X-Priority: 3 (Normal) X-MSMail-priority: Normal Parts/Attachments: www. infotech. monash. edu 16

e. Mail – the SMTP Model User Agent Local MTA Processing Queue MTA Relay Processing Queue Local MTA User Agent Mailboxes www. infotech. monash. edu 17

The SMTP Model • MTA: A mail transfer agent exchanges mail over a TCP/IP connection • System administrator is responsible for setting up the MTA • SMTP defines a MTA that implements a system based upon the spooling of messages. www. infotech. monash. edu 18

SMTP • First proposed in RFC 821 • Later updated in RFC 822 – replaced X. 400 • Commands HELO client identifies itself MAIL/RCPT identifies originator and recipient DATA for sending the contents of the mail QUIT terminates the mail exchange RSET aborts a transfer and resets both the ends VRFY to verify the address without actually sending NOOP forces server to respond with OK EXPN expands a mailing list TURN lets client and server switch roles www. infotech. monash. edu 19

Mailing Lists • To send mail to a group of users, mailing lists are often used. • A mail server is needed to distribute the mail messages to members of a mailing list. • List can be manually created, or may be automatically maintained. www. infotech. monash. edu 20

Mailing Lists • Listservers maintaining automated lists receive mail messages from new list members requesting that they be added to the list. • eg. subscribe FIT 2018_Notices • Self registration method… www. infotech. monash. edu 21

Mailing Lists • List members can also remove themselves from the list. • eg. unsubscribe FIT 2018_Notices • Messages will be sent to all members of the list when e-mail is posted to the listname email address on the computer that is hosting the list. eg. FIT 2018_Notices@webboard. netcomp. monash. edu. au www. infotech. monash. edu 22

Terminal Connectivity • Allows remote users to log into computers that are attached to the network. • Users can be located anywhere that there is a network connection. • As if they were sitting at a terminal that was physically attached to that computer. • Security implications: the conversation may not be private if using an internet connection www. infotech. monash. edu 23

Terminal Connectivity (cont’d) • eg. terminal session accessing the library computer • library. monash. edu. au (before 2000… now uses web interface) www. infotech. monash. edu 24

File Transfer Protocol (FTP) • Moving files from one computer To another over the Internet GET Assign 1. doc PUT COMPUTER A FTP Server COMPUTER B FTP Client www. infotech. monash. edu 25

FTP -- Anonymous ftp • To use ftp, a user normally must identify themselves with a username and password. • Having accounts for all possible users is impractical. • An anonymous user account is maintained on many ftp servers www. infotech. monash. edu 26

FTP -- Anonymous ftp • The anonymous account is restricted to certain areas of the server and will normally have restricted privileges (e. g. may only be permitted to read and not write). • Most systems require the user's e-mail address to be typed instead of a password. • Many ftp servers use the account ftp (its easier to type). • Most WWW browsers support ftp as a built in function making it easy to use file transfer www. infotech. monash. edu 27

News • All network of news servers around the Internet implements the Network News Transfer Protocol (NNTP). • These systems support a special-interest group type of information service. • Servers use peer-to-peer transfer (news feed) www. infotech. monash. edu 28

News • Messages can be posted to a news group and will then be copied to all news servers over a period of time. www. infotech. monash. edu 29

News • News messages can be read by anyone using a news client that is attached to a news server. • Most WWW browsers and email readers have NNTP plug-in applications www. infotech. monash. edu 30

Hyper. Text Transfer Protocol (HTTP) • Hyper. Text Markup Language • a simple markup language used to create hypertext documents that are portable from one platform to another • HTML documents are SGML documents • ISO Standard 8879: 1986 Information Processing Text and Office Systems; Standard Generalized Markup Language (SGML) www. infotech. monash. edu 31

HTTP (cont’d) • HTML describes the structure and organization of a document • It only suggests appropriate presentations of the document when processed • Tags define the start and end of headings, paragraphs, lists, character highlighting and links www. infotech. monash. edu 32

HTTP (cont’d) <html> <head> <title>CPE 2009 Lectures</title> </head> <body> <table width=“ 100%” cellspacing=“ 0“ cellpadding="0" border="0" > etc… www. infotech. monash. edu 33

HTTP (cont’d) www. infotech. monash. edu 34

HTTPD Administration Ref: http: //hoohoo. ncsa. uiuc. edu/docs/tutorials/ • • • Virtual directory structure Directory Indexing Security – Access control and user authentication – Secure server – chroot server – Kereberos, MD 5 authentications • • • CGI (Common Gateway Interface) Configurations Virtual Hosting Logfile rotations Starting, stopping, and restarting the daemon Multiple Directory. Index Keep. Alive Redirect Directives Server-side includes Imagemaps www. infotech. monash. edu 35

End… www. infotech. monash. edu