DSL Modem Router SlingLink SlingLink
Ethernet-connected PC
AC Power Line
Ethernet
Ethernet
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Project 19
Firewall
Configurations
for IM and Voice
over IP
What You??™ll Need
Your computer
Your router/firewall and firewall software
Broadband Internet connection
Your choice of IM or VoIP software
Cost: $0
Instant messaging isn??™t just about text messaging??¦and hasn??™t been for a long, long
time. Today we can use AOL Instant Messenger (AIM), Windows Live Messenger,
and Yahoo Messenger to share live webcam images, computer-to-computer voice
conversations, and computer-to-phone calls.
Adding to the diversity of our computers are Voice over IP (VoIP) applications
such as Packet8, Skype, and ViaTalk for computer-to-computer, computer-to-phone,
and phone-to-computer calls. Computer-based phone service is a relatively new but
increasingly popular means to connect to the huge domestic and international phone
systems, or simply chat between PCs.
Although all of these applications provide the same basic features??”voice over the
Internet??”they require unique configurations of both software and hardware firewalls.
This project gives you examples of firewall configurations that you need to set for common
VoIP, IM, remote control and video applications so that they will work properly
through your computer, network, and broadband connection.
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126 Project 19
Port and Protocol Definitions
As you??™ve explored networking, you??™ve undoubtedly run across myriad new terms??”
from IP address to protocol, TCP to UDP, and so on.
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