Transcript IETF 報告 UDLR-WG

Application of the Internet
1998/12/09
KEIO University, JAPAN
Mikiyo Nishida/[email protected]
Overview of this section
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E-mail
World Wide Web (WWW)
Connecting by telephone line
Other Common Application
Application for administrative use
Application for security
E-mail
• The most using application in the Internet
• E-mail service is constructed 2 parts.
– Mail messages transferring over the network
– User getting own mails
E-mail / SMTP
• SMTP - Simple Mail Transfer Protocol
– This protocol provides mail transferring
procedure between hosts/servers
– SMTP is very simple protocol (Simply,
delivering mails)
E-mail / sendmail
• “sendmail” is mail delivering deamon
– “sendmail” is working on Mail Server
– Each mail server’s “sendmail” deamon
transferring mails
E-mail / POP
• POP - Post Office Protocol
– This protocol provides the user downloading
mails from mail server
– Currently using POP3 (POP version3)
World Wide Web (WWW)
• The most famous Internet Application
• Killer Application
– Mostly the Internet traffic is occupied by
WWW
WWW / HTTP
• HTTP - Hyper Text Transfer Protocol
– This protocol provides the way of WWW
contents transferring
– HTTP is simple protocol
• send “GET (URL)” and reply contents
• HTTP service providing daemon called
“httpd”
WWW / URL
• URL - Uniform Resource Locator
– URL is the description of resource type (using
protocol), place
– example:
http://www.wide.ad.jp/index.html
ftp://www.sfc.wide.ad.jp/~west/hoge.zip
WWW / HTML
• HTML - HyperText Mark-up Language
– HyperText is the text including logical structure
(link, picture, character size, etc)
– HyperText can include related link information
– Web Browser is browsing HTML contents
WWW / Browser
• Browsing HTML text
– Formatting and displaying html text
– Following link in html text
– Integrating some Internet Service
– Famous browsers: Netscape Navigator,
Microsoft Internet Exploler
WWW / Java
• Java is one of programming language
(Developed by Sun Mircosystems)
• Java can program “Java Applet”
• Java Applet is runable on the WWW
Browser
Connecting by telephone line
• SLIP - Serial Line IP
– The protocol provides the way of transferring
IP Packet on the serial (telephone line, etc) line
• PPP - Point to point protocol
– PPP is upgrading SLIP
– Dynamic IP Address Assign
– CarriedmMany network information
Other Common Applications(1)
• FTP - File Transfer Protocol
– Sending and receiving remote file, local file
• TELNET
– Provides remote host’s terminal
– Login to remote system (UNIX)
Other Common Applications(2)
• DNS - Domain Name System
– Distributed Database system, matching IP
Address and hostname
– example:
203.178.143.111 <> myhost.wide.ad.jp
Application for network
administrative use
• ping
– checking network reachability
• traceroute
– tracing the route to destination
Application for Security
• SSL - Secure Socket Layer
– Encrypting and decrypting data at the socket
• SSH - Secure Shell
– Encrypting remote shell
– Hidden password and data by powerful
encrypting method