Keeping Your Computer Safe and Running Efficiently

1. Keeping Your Computer Safe and Running Efficiently

2. Backup Your System • It’s possible that your hard disk will crash and everything on your computer will be lost. IT HAPPENS EVERY DAY. • Make (at least) one duplicate of all files that are critical to you. • Make this duplicate on external media.

3. Backups (continued) • Backup Media • Floppy disk • External Hard disk • Tape Drive (but still used for servers) • CD/DVD • USB memory sticks

4. What to backup • Full backup • Duplicates everything on your disk • Incremental backup • Duplicates everything since the last full backup • Differential backup • Duplicates everything since the last differential backup (or full backup)

5. Backups – What I Do • I use slightly different strategies on my macs and on my windows machines. • I use an external hard disk and on occasion (say every month) make a full backup of my system. • I do not save old full backups • I also make full backups of “important” data. These backups are made to • External hard disk (monthly). Mac (Super Duper!) • Burned to CD (as needed usually monthly) • USB Flash memory sticks (very frequently) • On my macs, I use Time Machine • Dropbox for automatic backups of certain data

6. Backups –What I Do (continued) • On Windows • Registry backup • Restore point backups

7. Spyware • Spyware is software that is put on your system possibly without you being aware of it. • It is often installed during the process of installing other software. (Read your license agreement for details)

8. Spyware (cont) • Its purpose is to detect how you use your computer and send that information to others. • It may also create pop-up ads on your computer.

9. How to Remove Spyware • Use a spyware detection program and run it periodically. • I use Spybot S&D (search and destroy) • Others use AdAware. • I also use Microsoft Security Essentials. • http://www.pchell.com is a web site that has lots of useful information for Windows users. • Note that I haven not checked this site out thoroughly but in general I agree with the things that I have read there.

10. Anti-Virus Software • A virus is an unwanted or unexpected program usually designed to damage a computer, degrade its performance, or cause the computer to perform unwanted tasks (such as sending information to other computers)

11. How Does Your Computer Get a Virus? • From Downloaded Files • From attachments to e-mail messages • From macro files located in data files such as Word documents or Excel worksheets.

12. How does Anti-virus software work? • It checks files to see if they contain virii.

13. How does it recognize a virus? • Virii have characteristic patterns in them called “signatures”. • Anti-Virus software checks files to see if they contain these signatures.

14. What if a file has a virus? • The virus is removed from the file if possible • If it is not possible, then the file is “quarantined” in a special folder so that it will not be used. • The quarantined files can then be replaced by proper files.

15. Updating Anti-Virus Software • AV software consists of two parts: • The program that checks for virii • The data that contains the signatures of various virii. • The program also has built in schemes for testing for unknown virii. • Both the program and data should be kept up-to-date

16. How Do I update? • Download new data files. • Download updates to the program • With MicroSoft Security Essentials, this is done automatically. • For other software, I would download program updates monthly and data updates weekly.

17. A Problem • Do NOT use two anti-virus programs simultaneously. They will probably cause the computer to hang.

18. Subscriptions • Typically your anti-virus program has a one year license. • You are free to use the program past the end of the license BUT… • Most publishers of anti-virus programs will not allow you to download program updates once your license has expired.

19. When your subscription has run out… • You can replace your program with one that has no expiration date or one that is free. • Avast! was the AV software that I used before MS security essentials became available http://www.avast.com. • Currently I use MicroSoft Security Essentials which is free for personal use. http://www.microsoft.com/en-us/security_essentials/default.aspx

20. Firewalls • A firewall is a program that controls access to your computer from the Internet and controls access from your computer to the Internet.

21. Windows Firewall • Windows XP with service pack 2 (and all later versions of windows) have a free firewall program built in. • Unfortunately this firewall only controls what comes in to your computer.

22. Other Free Firewalls • http://www.iopus.com/guides/free-firewall.htm is a link to a Web site that tests firewall software. • NOTE that I haven’t examined their tests so I can’t vouch for the quality of the tests. • I used Zone Alarm Pro, which is not free. (Regular) Zone Alarm is free and I’ve tested it and been satisfied. But it does take some configuration. • Currently there is a firewall on my router which handles my home network

23. How Does a Firewall Work? • When “stuff” moves from one place to another it is broken down into packets, each packet is sent, and the packets are reassembled at the destination site. • Each packet has a header which gives information about what the packet contains. • The firewall can then allow packets to pass if their headers contain the “right” information.

24. Firewall Rules • Firewalls contain rules that determine whether packets are allowed to pass or are not allowed to pass. • Rules can be stated in two ways • Allow everything to pass except … • Allow Nothing to pass except…

25. What kind of Rules can Firewalls Have? • Rules about ports. • A port is a number that represents a logical connection to a program. • For example port 80 is for http connections and ports 20 and 21 are for ftp connections • If a firewall were set up to deny port 80 then your computer would not be able to read Web pages.

26. What kind of Rules can Firewalls Have? (cont) • Rules about locations. • A location is either a domain or an IP address. • A firewall could have a rule that says accept from 134.198.168.2. This rule would mean that anything that is on the literacy Web server (134.198.168.2 or www.cil.cs.scranton.edu) will be accepted.

27. What kind of Rules can Firewalls Have? • Application rules. • A firewall could have a rule that says deny any program the use of port 20 except ftp.exe, iexplore.exe, fileZilla.exe, or kompoZer.exe. This would keep your computer from being able to ftp files unless they were being ftp’ed by one of those programs.

28. Little Snitch • Little Snitch is a program that I use on my various macintosh computers. It costs about $25 but I found it on sale for half price a few years ago. • It works in conjunction with the built in firewall on my mac and allows me to monitor the traffic going OUT from my computer to the internet. • I use it because I’m slightly paranoid and I like to know when my programs are phoning home. • I don’t necessarily recommend that you do that.