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User Guide 2.3
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Allowing incoming services
Allowing incoming services
By default, the security stance of the SOHO is to deny unsolicited 
incoming packets to computers on the private network protected 
by the SOHO firewall. You can, however, selectively open your 
network to certain types of Internet connectivity. For example, if 
you would like to set up a Web server behind the SOHO, you can 
add an incoming Web service. 
It is important to remember that each service you add opens a 
small window into your private network and marginally reduces 
your security. This is the inherent trade-off between access and 
security.
Network address translation
All incoming connections through a SOHO automatically use a 
feature called dynamic network address translation (dynamic 
NAT). Without dynamic NAT, your internal, private addresses 
would not be passed along the Internet to their destination.
Furthermore, the SOHO protects your internal network by 
disguising private IP addresses. During an Internet connection, all 
traffic passed between computers includes their IP address 
information. However, due to the dynamic NAT feature, 
applications and servers on the Internet only see the public, 
external IP address of the SOHO itself and are never privy to the 
addresses in your private network address range when they 
exchange information with a computer behind your firewall. 
Imagine that you install a computer behind the SOHO with the 
private IP address 192.168.111.12. If this address were broadcast to 
the Internet, hackers could easily direct an attack on the computer 
itself. Instead, the SOHO converts the address automatically to the 
public, external address of the SOHO. When a hacker tries to