D-Link DI-1750 Reference Manual page 158

A router configured with NAT must not advertise the local networks to the outside. However, routing
information that NAT receives from the outside can be advertised in the stub domain as usual.
6.3.3 NAT Terminology
As mentioned previously, the term inside refers to those networks that are owned by an organization
and that must be translated. Inside this domain, hosts will have addresses in the one address space,
while outside, they will appear to have addresses in another address space when NAT is configured.
The first address space is referred to as the local address space and the second is referred to as the
global address space.
Similarly, outside refers to those networks to which the stub network connects, and which are generally
not under the control of the organization. As we will discuss in the following section, a host residing in
an outside network can/must be translated into a certain address, and it can be a local or a global
address.
Anyhow, NAT uses the following definitions:
♦ Inside local address—The IP address that is assigned to a host on the inside network. The address
is probably not a legitimate IP address assigned by the Network Information Center (NIC) or service
provider.
♦ Inside global address—A legitimate IP address (assigned by the NIC or service provider) that
represents one or more inside local IP addresses to the outside world.
♦ Outside local address—The IP address of an outside host as it appears to the inside network. Not
necessary a legitimate address, it was allocated from address space routable on the inside.
♦ Outside global address—The IP address assigned to a host on the outside network by the owner of
the host. The address was allocated from globally routable address or network space.
6.3.4 NAT Configuration Task List
Before configuring any NAT translation, you must know your inside local addresses and inside global
addresses. To configure NAT, perform the optional tasks described in the following sections:
♦ Translating Inside Source Addresses
♦ Overloading an Inside Global Address
♦ Translating Overlapping Addresses
♦ Providing TCP Load Distribution
♦ Changing Translation Timeouts
♦ Monitoring and Maintaining NAT
6.3.5 Translating Inside Source Addresses
You can translate your own IP addresses into globally unique IP addresses when communicating
outside of your network. You can configure static or dynamic inside source translation as follows:
Static translation establishes a one-to-one mapping between your inside local address and an inside
global address. Static translation is useful when a host on the inside must be accessible by a fixed
address from the outside.
Dynamic translation establishes a mapping between an inside local address and a pool of global
addresses.
Figuer 6-1 illustrates a router that is translating a source address inside a network to a source address
outside the network
Model Name
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