Keeping Your Computer Safe and Running Efficiently

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.

Backups (continued)

Backup Media Floppy disk External Hard disk Tape Drive Burn to CD/DVD

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)

Backups – What I Do 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) Burned to CD (as needed usually monthly) USB Flash memory sticks (very frequently)

Backups –What I Do (continued)

Registry backup Restore point backups

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)

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.

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 AntiSpyware (beta). http://www.pchell.com/support/spyware.

shtml reviews various products. Note that I haven not checked this site out

thoroughly

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)

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.

How does Anti-virus software work?

It checks files to see if they contain virii.

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.

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.

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

How Do I update?

Download new data files (I do it weekly). I recommend that you do it about that often. You can set your program to automatically download updates.

Download updates to the program. I do that monthly. I recommend that you do that about as often.

A Problem

Do NOT use two anti-virus programs simultaneously. They will probably cause the computer to hang. At least that’s the case with Norton

Anti-virus and McAfee Anti-Virus.

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.

When your subscription has run out…

You can replace your program with one that has no expiration date or one that is free.

www.grisoft.com AVG is one such example

www.free-av.com Antivir is another one

Others can be found online.

Firewalls

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

Windows Firewall

Windows XP with service pack 2 has a free firewall program built in to it.

Unfortunately this firewall only controls what comes in to your computer.

Other Free Firewalls http://www.iopus.com/guides/free-firewall.h

tm 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 use 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.

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.

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…

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.

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.

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, coreftp.exe, or nvu.exe. This would keep your computer from being able to ftp files unless they were being ftp’ed by one of those programs.