A web browser is software that displays web pages and allows users to navigate between them. It takes URL requests, communicates with web servers to retrieve content, and renders received files and scripts to display webpages to the user. Common functions of browsers include fetching webpages and embedded content like images, running client-side scripts, and handling cookies and other data used to maintain state across webpage visits.

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2.  Web Browser is a software that is installed on your
computer. It is used to locate and display web
pages and other online content. Behind the scene,
a browser performs lot of functions but its key role
is to take your request to the web server and bring
the content to you and display it.
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3.  Finds the web server
 Takes your request and transports data
 Transports cookies
 Brings back content
 Processes the content and renders it
 Executes scripts (code)
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4.  Enter a URL into a browser
◦ Breaks the URL into a host + path
 Asks a DNS server for an IP address for the host
 DNS server returns a IP address for that host
◦ Browser sends a request to the IP address
 Path is used to determine what file to obtain
 Data for web server to process, maintain state
 Server replies to the request – HTML, PDF, mp3, etc.
◦ Browser reads the HTML file and asks for all the files referenced in the
original HTML file
 These additional files could be images, more HTML, or other types on content.
 Additional files could reside on different hosts requiring more DNS requests
 After browser gets all the pieces, it processes the data and renders a single
“page”
 Non-HTML file are opened in the browser of associated application.
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5.  Internet Explorer (Microsoft)
 Firefox
 Safari
 Chrome
 Opera
 Konqueror
 Several others
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7.  Data set by the web site owner
 Data you enter in the form
 Information you request
 Cookies
 Operating System, browser type
 Your IP address – can help determine your
geographical location
 Referring page
 Much more
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8.  Example URLs:
◦ http://www.somesite.com
◦ https://www.somesite.com
http – data is unencrypted while transport from the web
browser to the web server
https – data is encrypted while transported from the
browser to the web server
Make sure that data you don’t want anyone to eavesdrop is
encrypted – https in the address bar; closed lock in the
status bar
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10.  Use one browser for your “important” surfing and another for “casual”
browsing. That way data from one can't leak to the other (generally
speaking)
 Always keep an eye on the URL in the address bar
 Read, Pause before clicking on anything
 Logout and always close the browser window
 Nothing is “really” free. Only download
files from websites you trust
 Don’t open attachments forwarded from your friend’s computer is
corrupted
 Logout and close browser/tab
 The browser’s back and refresh features can be used to steal
passwords from insecurely written applications.
 Be careful of Google search results
 Always type URL for sites where confidential information is in use.
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11.  Always use the red “X”
in the corner of a pop-up
screen
 Never click “yes,”
“accept” or even “cancel”,
because it could be a trick
that installs software on
your PC
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12. An Internet firewall
is like a moat
around a castle,
creating a barrier
between
your computer and
the Internet
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13.  Search results may contain malicious web site
 Does it make sense?
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14.  Keep passwords private and create ones that are
hard to “crack”
 Use password checker (See resources)
 Never share your passwords with friends or be
tricked into giving them away
 Do not email login name and password together
 Do not text message your login information
 If you do have to write, keep the paper in safe
keeping
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15.  Avoid creating passwords using
◦ Dictionary words in any language.
 Words in all languages are vulnerable
 Words spelled backwards, common misspellings, and
abbreviations
◦ Sequences or repeated characters.
 Examples: 12345678, 222222, abcdefg, or adjacent letters
on your keyboard (qwerty)
◦ Personal information.
 Your name, birthday, driver's license, passport number, or
similar information
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16.  Web browser
◦ http://en.wikipedia.org/wiki/Web_browser
 How browser works
◦ http://taligarsiel.com/Projects/howbrowserswork1.htm
 Securing your browser
◦ http://www.cert.org/tech_tips/securing_browser/
 Analysis: Browser Security
◦ http://www.networkcomputing.com/wireless/analysis-browser-
security.php
 Microsoft Online Safety
◦ http://www.microsoft.com/protect
 Get Wise
◦ http://www.getnetwise.org
 Password Checker
◦ https://www.microsoft.com/protect/fraud/passwords/checker.aspx?WT.mc
_id=Site_Link
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