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Telnet and FTP. Telnet Lets you use the resources of some other computer on the Internet to access files, run programs, etc. Creates interactive connection.

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Presentation on theme: "Telnet and FTP. Telnet Lets you use the resources of some other computer on the Internet to access files, run programs, etc. Creates interactive connection."— Presentation transcript:

1 Telnet and FTP

2 Telnet Lets you use the resources of some other computer on the Internet to access files, run programs, etc. Creates interactive connection with remote machine To use:  Need telnet application software – Microsoft Windows Telnet (built into Windows 95 and greater) Macintosh Terminal (built into Mac OS X and greater)  Need an account on remote machine – you will be prompted login and password OR  Some systems will allow you to login as guest to access some resources like databases  Example: telnet

3 rsh rsh – remote shell Another protocol that allows us login access Use the rlogin (remote login) command in the terminal window Example: rlogin –l username (you can omit –l username if your username is the same on both systems) rlogin skips past the login: prompt and will present the Password: prompt

4 ssh ssh – secure shell ssh is another popular protocol that allows us login access  More secure than telnet or rsh since it encrypts all data that passes over the network  This can prevent a third party from spying on the network traffic and reading your sensitive information (like your password) Example: slogin –l username (Avoid using the generic with slogin or you may get a warning message about conflicting host keys) ssh secure shell replaces other, insecure terminal applications like Telnet and FTP

5 FTP FTP – file transfer protocol Allows you to send files and directories over a network FTP client – software that allows you to connect to an FTP server on the Internet  Originally clients were text-based and used commands (much like UNIX) – these still exist  Graphical based FTP clients now exist; e.g.: WS_FTP File Manager through Blackboard  Clients transfer data in one of two modes: ascii (for text files) and binary (for all others) Need an account on remote system (username and password) but some sites allow anonymous ftp  Login with anonymous  Enter email address as password  Good for downloading software and database information (otherwise information would have to be sent sneakernet or as an email attachment)

6 Viruses Downloading files from the Internet introduces the possibility that your computer could become infected with a virus Virus – generic term applied to a wide variety of malicious programs that invade your computer; not all cause damage (but many do) Computer virus is similar to biological virus in that it passes from computer to computer like a biological virus passes from person to person Platform specific (e.g., a Windows virus will not infect UNIX system, etc.) Types:  Traditional virus – attach to programs or data files, replicate themselves, then damage data, hard disk, etc.  Worms – stand alone programs designed to infect networks. They travel from network to network, replicating themselves along the way.  Trojan Horse program – legitimate program with hidden code that is activated by a trigger that causes the code to execute  Email Virus – gets transmitted in email messages

7 Viruses - Prevention 1. Use a secure operating system 2. Run antivirus software (aka virus detection software) Scanner – checks files to see if they were infected: Looks for characteristic data patterns found in programs infected by known viruses Determines if a program’s file size is changed Eradication program – disinfects by wiping virus from hard drive Innoculators – will prohibit a program from running if it detects a virus 3. Keep antivirus software up-to-date 4. Avoid programs from unknown sources (like Internet) including mail attachments from unknown senders 5. Don’t use pirated copies of software; purchase commercial software on CDs as they cannot be modified 6. Don’t double-click on an email attachment that contains an executable (file extension like.exe,.com,.vbs) and don’t run macros in a document unless you know what they do 7. Back up files regularly just in case…

8 Adware and Spyware Adware – software that displays ads on your computer  Ads pop up even if you are not browsing the Web  Some companies provide free software in exchange for advertising on your display Spyware – software that sends your personal information to a third party without your permission or knowledge; collects info about:  Web sites you visit  Sensitive info like your username and password  Some companies use collected info to send you unsolicited targeted ads Both cause performance issues with your computer like:  Computer hangs frequently, slows down, does not work properly  Hijacks your Web browser, gives you a new start page

9 Adware and Spyware - (con’t) Usually install secretly on your computer by either:  Tricking you into clicking a link that installs it; e.g., it opens a Window dialog box, you click Cancel and it installs it  Installing freeware that installs it; e.g., free file sharing program might secretly install spyware on your computer To protect against adware and spyware:  Use antivirus software as newer products now include adware and spyware scanning; Some ISPs are now providing protection from adware and spyware as well  Make sure that the programs you install do not contain adware: Read license agreement carefully Check the publisher’s Web site carefully Search the Internet for the name of the program and the keywords adware and spyware  Install a pop-up blocker to prevent adware and spyware pop-up windows (then you won’t accidently click a deceptive link)  Do not unwittingly install adware or spyware; e.g., you may see a dialog box to verify that you want to install a program – click No

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