WatchGuard Technologies Firebox SOHO 6.1 ユーザーズマニュアル

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User Guide
5
How Does the SOHO 6 Process Information?
Port numbers
The port numbers are used by computers at both the sending and 
receiving end to determine the particular program or application 
for each connection.
How Does the SOHO 6 Process Information?
Services
A service is the combination of protocol(s) and port numbers 
associated with a specific program or application type. To simplify 
configuration of your SOHO 6, WatchGuard configured versions 
of several common services are available for your use.
Network Address Translation
All outgoing connections through a SOHO 6 automatically use a 
feature called dynamic NAT (Network Address Translation). 
Without dynamic NAT, your trusted, private addresses are passed 
along the Internet to their destination.
In addition, the SOHO 6 protects your trusted network by 
disguising private IP addresses. During an Internet connection, all 
traffic passed between computers includes IP address information. 
However, because of the dynamic NAT feature, applications and 
servers on the Internet only see the public, external IP address of 
the SOHO 6 itself and are never aware of the addresses in your 
trusted, network address range.
Imagine that you install a computer behind the SOHO 6 with the 
IP address 206.253.208.100. If this address were broadcast to the 
Internet, hackers could easily direct an attack on the computer 
itself. Instead, the SOHO 6 converts the address automatically to