Specifications

VoiceFinder VoIP Gateway Configuration Guide (APOS 2.0) Release Version 3.1
AddPac Technology Co., LTD
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2.7. Configuring NAT (Network Address Translation)
One of the major problems with today’s internet may be the shortage of supplying IP addresses
to meet the demand. Network Address Translation (NAT) is one of the ways to resolve this
problem. NAT translates the private IP address which is used within the network to a different
type of IP address (public IP address) when the IP address goes out of the network. In the other
way, NAT translates the public IP address coming from the outside into the inside of the
network.
NAT can be used in the following several purposes:
z NAT enables a user to connect the private IP network to the global internet when
authorized public IP address is not enough to assign to all terminals.
NAT is to be configured with the gateway which is located between the border of Stub
domain (commonly called as inside network) and the public network (commonly called as
outside network). At this location, NAT converts the packet from the private IP address in the
inside network to the unique public IP address before it sends out the packet to the outside
network.
z Sometimes an administrator needs to change the inside network address for security and
other management purposes. This change may require a lot of work, but using NAT, the
address can be translated with easy.
z Sometimes an administrator needs to perform load-sharing of TCP traffic. In this case, TCP
Load Distribution can be done by mapping many Local IP Addresses to one Global IP
Address. To access from the outside, Global IP Address can be accessed as one, then it is
divided by TCP sessions the load can be distributed.
Information