Symantec Norton Personal Firewall 2003, User Manual

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Contents 9
Appendix A Troubleshooting Norton Personal Firewall
Troubleshoot Norton Personal Firewall problems ......................... 112
What is wrong with this Web site? ........................................... 112
Why can’t I post information online? ....................................... 113
Why did an email message I sent never arrive? .................... 113
Why doesn’t Norton Personal Firewall notify me before
letting programs access the Internet? .............................. 114
Why can’t I print to a shared computer or connect to a
computer on my local network? ......................................... 114
Why can’t I connect to the Internet via my cable
modem? ................................................................................... 114
How can a Web site get my browser information? ................ 115
Appendix B About the Internet
How information is transmitted over the Internet ........................ 118
About UDP ...................................................................................... 120
About ICMP .................................................................................... 120
About IGMP .................................................................................... 120
How Web information is located on the Internet ........................... 120
Requesting a page ........................................................................ 121
Understanding URLs .................................................................... 121
How ports identify programs on servers ......................................... 122
How computers are identified on the Internet ............................... 123
Appendix C Understanding Internet risks
Risks from hackers ............................................................................... 125
The process of a hacker attack ................................................... 125
Risks from active content ................................................................... 128
Risks from inappropriate content and activities ............................ 129
Blocking site and newsgroup categories ................................. 129
Restricting access to programs .................................................. 129
Risks to your privacy ........................................................................... 129
Sending private information ...................................................... 129
Understanding cookies ................................................................ 130
Blocking cookies ........................................................................... 130
Tracking Internet use .................................................................. 131
Risks from Trojan horses and viruses .............................................. 131
The likelihood of being attacked ....................................................... 132