WHAT IS THE INTERNET?

•IT IS NOT OWNED BY ANYONE•IT IS NOT HOMOGENEOUS•NO CENTRALIZED MANAGEMENT•OVERSIGHT ORGANIZATIONS

WHAT IS THE INTERNET?

PROVIDES COMMUNICATIONS SERVICES• E-MAIL• FILE TRANSFER• ONLINE CHAT• AUDIO & VIDEO• WORLD WIDE WEB

INTERLINKED WEB PAGESSEARCHINSTANT MESSAGINGE-SHOPPING

WHAT IS THE INTERNET?IT IS: COMPLEX WORLDWIDE PUBLICLY ACCESSIBLE PACKET SWITCHING XMISSION TECHNOLOGY HAS INTERCONNECTED NETWORKS

• DOMESTIC• ACADEMIC• BUSINESS• GOVERNMENT• COMMERCIAL

INTERNET HISTORY

•1957 SPUTNIK

•1958 DOD-ARPA, ADVANCED RESEARCH PROJECT AGENCY FORMED

•1965 1st EMAIL, TIMESHARE TO MAINFRAME COMPUTER

•OCT. 1968 ARPANet WORKING GROUP MET AT SRI

•NOV. 1969 ARPANET UCLA-SRI COMPUTER LINK ESTABLISHED

•DEC. 1969 UCLA-SRI-UCSB-UofUTAH LINK-UP

•1971 1ST NETWORK E-MAIL TRANSMITTED BETWEEN COMPUTERS

•1973 FTP PROTOCOL INTRODUCED/IMPLEMENTED BY ARPANet

•1973 ROBT. KAHN & VINTON CERF BEGAN WORK ON TCP/IP

•1975 1ST COMMUNICATION TEST USING TCP/IP

•1975 ARPA TURNED ARPANet OVER TO DCA

•1978 PACKET SWITCHED NETWORKS EXPANDED TO EUROPE

INTERNET HISTORY – CONTD.

•1979 CompuServ OFFERS E-MAIL SERVICE

•1981 NETWORKS EXPANDED TO CANADA, HONG KONG, & AUSTRALIA

•1982 TCP/IP ADOPTED FOR ALL MILITARY COMPUTER NETWORKS

•1983 - TCP/IP REPLACES PRIOR PROTOCOL USED BY ARPANet- MILITARY PORTION OF ARPANet SPUN OFF TO MILNET- DOMAIN NAME SYSTEM INVENTED

•1986 NATIONAL SCIENCE FND NETWORK(NSFNetwork) ON LINE REPLACING ARPANet

•1988 - NSFNet PRINCIPAL INTERNET BACKBONE WORLDWIDE- NSFNet CREATED 5 SUPER CONDUCTOR CENTERS- NSFNet WAS THE PRINCIPAL INTERNET BACKBONE

•1991 TIM BERNERS-LEE RELEASES WORLD-WIDE WEB (WWW)

• 1993 MOSAIC (PRECURSOR TO NETSCAPE) MADE AVAILABLE TO PUBLIC

•1994 NSFNet TRAFFIC PASSES 10 TRILLION BYTES/MONTH

•1995 NSFNet DECOMMISSIONED; INTERNET TURNED OVER TO ISPs & TRANSMISSION CARRIERS

PROTOCOLS•RULES OR CONVENTIONS•TCP (TRANSMISSION CONTROL PROTOCOL) – CONTROLS

PACKAGING OF DATA INTO PACKETS AT SOURCE AND RECOMBINES DATA AT DESTINATION

•IP (INTERNET PROTOCOAL) – CONTROLS THE ROUTING OF DATA OVER THE INTERNET

•UDP (USER DATAGRAM PROTOCOL) – ALSO CONTROLS PACKAGING OF DATA INTO PACKETS SIMILAR TO, BUT NOT AS RELIABLY TRANSMITTED, AS TCP. USED FOR

STREAMING AUDIO/VIDEO

TCP/IP STACK LAYER

INTERNET DOMAIN NAMEDOMAIN NAME

racorinda@pacbell.net

http://www.yahoo.com

http://finance.yahoo.com.us/marketupdates/overview.html

1st LABEL TO LEFT OF “/” IS THE TOP DOMAIN, GEOGRAPHICALLYus=U.S., ca=Canada, fr=France, de=Germany, ru=Russia, es=Spain, jp=Japan 2nd LABEL TO LEFT IS THE TOP DOMAIN, GENERIC

.biz, .com, .edu, .info, .net, .org, .info, .mil, .arpa, .museum

3rd LABEL TO LEFT IS SECOND LEVEL DOMAIN

REMAINING LABELS TO LEFT ARE SUB-DOMAINS UNDER CONTROL OF THE SECOND LEVEL DOMAIN

INTERNET DOMAIN NAMEIP ADDRESS

DOMAIN NAME REQUEST

IP Request:finance.yahoo.com/

NAME SERVER FOR LOCAL ISP

IP Request:yahoo.com

Address For:yahoo.com

IP Request:Finance

Address For:Finance

Communications Established

ROOT SERVER

NAME SERVER FOR yahoo.com

1

222

3

7

4

5

6

http://finance.yahoo.com/marketupdates/overview.html

FINANCE SERVER AT YAHOO.COM

YAHOO.COMGATEWAY SERVER

YAHOO.COMNAME SERVER

FINANCE.YAHOO.COMSERVER

FIREWALL

BRIDGE/SERVER

DATA PACKET

PORTS – VIRTUAL ENTRANCEWAY BETWEEN YOUR COMPUTER & THE INTERNET

TOTAL AVAILABLE PORTS = 65,535

PORT NO. DESCRIPTION

20/TCP FTP—data

21/TCP FTP—control (command)

23/TCP,UDP Telnet protocol—unencrypted text communications

25/TCP,UDP Simple Mail Transfer Protocol (SMTP)—used for e-mail routing between mail servers

53/TCP,UDP Domain Name System (DNS)

70/TCP Gopher protocol

80/TCP Hypertext Transfer Protocol (HTTP)

109/TCP Post Office Protocol 2 (POP2)

110/TCP Post Office Protocol 3 (POP3)

115/TCP Simple File Transfer Protocol (SFTP)

220/TCP,UDP IMAP, Interactive Mail Access Protocol, version 3

465/TCP SMTP over SSL

513/TCP Login

531/TCP,UDP AOL Instant Messenger, IRC

532/TCP netnews

OUTGOING E-MAIL: SMTP Port 115 POP3 Port 110SMTP W/SSL Port 465 POP 3 W/SSL Port 995

IF YOU USE A NON-STANDARD PORT YOU MUST SPECIFY THE PORT NUMBER BEING USED IN THE URL; E.G., http://www.parishilton.com:81/

E-MAIL

METHOD OF WRITING, SENDING, RECEIVING AND SAVING MESSAGES USING AN ELECTRONIC COMMUNICATION SYSTEM

•COMMON PROTOCOLS - POP (POST OFFICE PROTOCOL): DELETES MSGS ON SERVER WHEN D/L - IMAP (INTERNET MESSAGE ACCESS PROTOCOL): LEAVES MSGS ON SERVER - WEBMAIL (HTTP PROTOCOL): ACCESS MAIL SERVER WITH BROWSER - SMTP (SIMPLE MAIL TRANSFER PROTOCOL): STANDARD FOR OUTGOING MAIL - PROPRIETARY PROTOCOLS: FOR INTRANET SYSTEMS, LIKE AOL/COMPANIES - HTML (HYPERTEXT MARKUP LANGUAGE): MESSAGE BODY - MIME (MULTIPURPOSE INTERNET MAIL EXTENSIONS): PERMITS TEXT OTHER THAN ASCII, TEXT & NON-TEXT ATTACHMENTS, AND MULTIPLE PART MSGS.

Attach:

HEADER

BODY

CLIENT

PORTSMTP: 115/465HTTP: 80AOL: 531

PORTPOP3: 110/995IMAP4:220/993

EMAIL TRANSMISSION DIAGRAMsmtp.att.yahoo.com

WORLD WIDE WEB (www) or“The Web”

•SIR TIMOTHY BERNERS-LEE CREATED WEB TECHNOLOGY

•MARC ANDREESSEN CREATED THE FIRST BROWSER