User`s guide

VoiceFinder AP2120 VoIP Gateway User’s Guide Version 1.00
AddPac Technology Co., Ltd. -
106 -
[NAT Glossaries]
z Inside local address: The address set in the host of the inside network
z Inside global address: An IP given by the Network Information Center
(NIC) or the service provider. There are more than one IP address
representing internal local IP addresses in the outside network.
z Outside local address: The IP address of the host in the outside network.
The outside local address appears in the inside network.
z Outside global address: The address that the host owner gave to the host
in the outside network. The outside global address is allocated to the
globally routable addresses or networks.
NAT supports static address translation and dynamic address translation.
z Static Address Translation: When there is any access request from the
outside network, NAT regularly maps an unregistered IP address of the
internal host to a certified IP address, and converts the registered IP
addresses to an unregistered IP address. Also, if an internal host accesses
to the outside network, NAT performs the opposite and converts addresses.
z Dynamic address Translation: NAT keeps registered IP addresses, and
when an inside network requests to access to the outside network, NAT
allocates one of IP addresses that it keeps. However, if all registered IP
address that NAT keeps are in use, NAT cannot allocate any registered IP
address to the inside network.
VoiceFinder AP2120 Gateway usually supports both of NAT function and Port
Address Translation (PAT) function.
NAT function converts several internal, unregistered IP addresses into several
external, registered IP addresses. And PAT function converts several internal,