Скачать презентацию TCP IP Servers LPD Printing SMTP Mail Скачать презентацию TCP IP Servers LPD Printing SMTP Mail

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  • Количество слайдов: 34

TCP/IP Servers • LPD (Printing) • SMTP (Mail) • FTP (File Transfer) • NTP TCP/IP Servers • LPD (Printing) • SMTP (Mail) • FTP (File Transfer) • NTP (Network Time) • NNTP (News) • WEB

Network Printing • Configure the printer hardware on the host system by using either Network Printing • Configure the printer hardware on the host system by using either the parallel or usb interfaces. • Add the Windows component “Other Network File and Printing Services” – uses port 515 (LPD) for BSD Unix printing • Or get HP Jet. Admin software for the system – uses port 9100 (Jet Direct) • Or get a network ready printer

Printing cont. • Printer protocols: – Postscript (Adobe) • is a language executed by Printing cont. • Printer protocols: – Postscript (Adobe) • is a language executed by the printer • is very configurable – PCL (Hewlett Packard) • is a bit mapped graphics mode • is faster than postscript – ASCII (text) • Plain old printable characters

Printer Setup (Network Ready) • Plug it in to the wall outlet (power) • Printer Setup (Network Ready) • Plug it in to the wall outlet (power) • Plug in the network cable • Power up the printer • Print the configuration sheet • Register the printer address (preferably non-routable)

Printing • PDL (Print Description Languages), basically printer drivers. • Provide a standard interface Printing • PDL (Print Description Languages), basically printer drivers. • Provide a standard interface from the application to the printer.

Printer maintenance • Expendable supplies (paper and toner) • How to fix a paper Printer maintenance • Expendable supplies (paper and toner) • How to fix a paper jam • Monitor the printer output bin • Monitor the print quality • Clean the printer

Simple Mail Trasnsfer Protocol • The protocol is very simple • Uses port 25 Simple Mail Trasnsfer Protocol • The protocol is very simple • Uses port 25 • All files are ascii text • Syntax: user@host. domain • Mail relay: user%host 1@host 2. domain • Mail Exchange (MX) – Allows mail server redirection

SMTP Mail Servers • POP 2, POP 3 – – Uses port 109 or SMTP Mail Servers • POP 2, POP 3 – – Uses port 109 or 110 Post Office Protocol, mail transfers to client, download all mail to the client (older protocol, replaced by): • IMAP – – Uses port 143 Internet Message Access Protocol, mail stays on server – Better for mobile (transient) clients • Webmail – uses a Web interface to access mail

Mail Clients • Eudora – Commercial • Netscape Messenger – Comes with Netscape • Mail Clients • Eudora – Commercial • Netscape Messenger – Comes with Netscape • Outlook – Comes with Windows 9 x, 2000 • Webmail, Groupwise – Uses any web browser

Client Setup • Client can have separate mail server and smtp server. • Mail Client Setup • Client can have separate mail server and smtp server. • Mail server is where our mail is received • SMTP server is where we send our messages • The Mail server can have virus and spam filters

Spamming • Mail Relaying to an off site recipient • Testing SMTP mail – Spamming • Mail Relaying to an off site recipient • Testing SMTP mail – abuse. net • Configuration to prevent SPAM – allow only local domain relays to internet

Headers • From • Date: • Subject: • To: • Resent-date: • Resent-from: Headers • From • Date: • Subject: • To: • Resent-date: • Resent-from:

Attachments • Using mail to transfer files • Simple operation • Incompatible programs – Attachments • Using mail to transfer files • Simple operation • Incompatible programs – Word for MAC vs. Word for PC –. pdf solves the compatibility problem • Dangers (viruses, trojan horses) – Executable programs that the client downloads and automatically executes

Encoding Methods • Binary Files (programs, sound, video) • UUENCODE (UNIX) – one file Encoding Methods • Binary Files (programs, sound, video) • UUENCODE (UNIX) – one file per encode • MIME (WWW, POP, IMAP) – multiple files per encode • Bin. Hex (Apple) – one file per encode

SMTP Example 1> telnet cc. usu. edu 25 2> 220 grumpy. usu. edu – SMTP Example 1> telnet cc. usu. edu 25 2> 220 grumpy. usu. edu – ESMTP Server (PMDF V 5. 2 -32) 1> HELO pc 15. logan. tv 2> 250 grumpy. usu. edu Ok, “port 32443”@techsun. cs. usu. edu” [129. 123. 7. 33] 1> MAIL From: 2> 250 2. 5. 0 Address Ok. 1> RCPT To: 2> 250 2. 1. 5 bobw@cc. usu. edu Ok. 1> DATA 2> 354 Start Mail input; end with 1> Date: Sat, 22 Mar 1998 13: 26: 31 MST 1> From: student 11@pc 15. logan. com 1>Subject: Meeting tomorrow

SMTP Example cont. 1> The meeting is TOMORROW at 3: 00 PM! 1> 1>. SMTP Example cont. 1> The meeting is TOMORROW at 3: 00 PM! 1> 1>. 2> 250 2. 5. 0 Ok 1> QUIT 2> 221 2. 3. 0 Bye received. Goodbye.

FTP • File Transfer Protocol – User – Anonymous • GET/PUT/DEL/CWD – GUI Interface FTP • File Transfer Protocol – User – Anonymous • GET/PUT/DEL/CWD – GUI Interface • Binary/Ascii • Hash

FTP Example • requires 2 ports • telnet ftp. remotesite. com 21 – – FTP Example • requires 2 ports • telnet ftp. remotesite. com 21 – – – 220 ftp. remotesite. com FTP server ready user anonymous 331 password required for anonymous password user@cc. usu. edu 230 user anonymous logged in PORT 1200

FTP Example cont. • • PORT 129, 123, 7, 55, 4, 76 200 PORT FTP Example cont. • • PORT 129, 123, 7, 55, 4, 76 200 PORT command successful pwd 257 “/export/guest/bobw” is current directory RETR. /. login 150 ASCII data connection for. /. login(129. 123. 7. 55, 1100)(795 bytes) QUIT

NTP • Network Time Protocol • • – Uses port 123 UDP (User Datagram NTP • Network Time Protocol • • – Uses port 123 UDP (User Datagram Protocol) Atomic Clock Synchronization Multiple Servers Used for – – – Distributed Databases Client/Server Security

Clock Synchronization mt mr Time Server Time Client Tround = mt + mr time Clock Synchronization mt mr Time Server Time Client Tround = mt + mr time = t Clock set is t + Tround/2

NNTP • Network News Transfer Protocol – Uses port 119 • Distributed Bulletin Board NNTP • Network News Transfer Protocol – Uses port 119 • Distributed Bulletin Board – Uses a tree hierarchy • Minimizes Duplicate messages/disk space • Tree based distribution • Store and Forward

Web Browsers • Mosaic – More or less the first web browser • Netscape Web Browsers • Mosaic – More or less the first web browser • Netscape – Became extremely popular very quickly • Microsoft Internet Explorer – Plays catch up with Netscape • Hot. Java – Sun Microsystems Browser

Web Browsers Cont. • Web Browsers can cache pages and pictures locally to speed Web Browsers Cont. • Web Browsers can cache pages and pictures locally to speed up access • Web Browsers can use a proxy server to remotely cache pages and pictures for many systems. • The proxy can act as a firewall and IP translator.

Web Servers • Apache • Roxen • Netscape • Microsoft – IIS Web Servers • Apache • Roxen • Netscape • Microsoft – IIS

Web Servers Cont. • Use http (hyper text transfer protocol) to create file and Web Servers Cont. • Use http (hyper text transfer protocol) to create file and service access • Can have virtual servers to save IP addresses • Can have additional ports (services) • Most of the fancy stuff is done by the browser.

HTML • • • Hyper Text Markup Language Uses ascii text and commands Automatically HTML • • • Hyper Text Markup Language Uses ascii text and commands Automatically formats text Sets up hyper links and displays pictures Connects to services such as ftp Start with and end with

HTML Cont. • <BODY> • <a href=“http: //www. usu. edu></a> • <a image=“fred. gif”></a> HTML Cont. • • • •

  • Hello
    • •

    XML • e. Xtensible Markup Language • Extends basic HTML to aid in creating XML • e. Xtensible Markup Language • Extends basic HTML to aid in creating documents and document systems. • Creates access to data bases

    CGI’s Common Gateway Interface • Allow Web browsers to execute programs on the Web CGI’s Common Gateway Interface • Allow Web browsers to execute programs on the Web server. • Uses: Mail, finger, database, animation, sound • Found in /cgi directory in the Web page home • Are executable C, perl, java, or shell programs

    ASP • Active Server Pages • Similar functions to CGI’s • Can do access ASP • Active Server Pages • Similar functions to CGI’s • Can do access counters, database access and online forms (fill in the blank)

    PHP • Personal Home Page Tools • Language for creating Web programs • Syntax PHP • Personal Home Page Tools • Language for creating Web programs • Syntax is similar to Basic

    Java • Developed by Sun • C++ context • Builds GUI’s (Graphical User Interfaces) Java • Developed by Sun • C++ context • Builds GUI’s (Graphical User Interfaces) • Handles animated objects on the web page

    Security and the WEB • • • WEB files must be world readable. The Security and the WEB • • • WEB files must be world readable. The WEB server may be run by root CGI’s can be dangerous security holes. • PHP, ASP, and VBscripts can have security holes (buffer overflows) • WEB servers are searched by many search engines that broadcast your data.