Compatible Systems 5.4 - Manual (Page 248)

242 Chapter 14 - General
> Internal Range
This is the address range of the internal NAT network. This range will be
translated into the range of IP addresses defined by the External Range. Any
interface or subinterface on the device which is part of the same network as
the Internal Range is considered to be an internal NAT port.
This window displays a list of all entered Internal Range but is not used to add
or modify the entries. To add or modify the entries, you must access the NAT
Map Dialog Box by selecting the New or Modify buttons above the Internal
Range window.
External Range
This is the address range of the external NAT network. This range will be
translated into the range of IP addresses defined by the Internal Range. The
address or range of addresses specified must be a valid, globally recognized
Internet address (or addresses) which can be routed on the network.
If only a single Internet IP address is available, then the External Range must
be the same as the IP address on the IP port communicating with the Internet.
In this case, care must be taken not to create a one-to-one translation pair
using this IP address in the NAT Mapping Dialog Box (under Global/Nat
Mapping). If a range of addresses is specified, the NAT software makes the
decision about which Internet address is assigned to outgoing packets.
This window displays a list of all entered External Range but is not used to
add or modify the entries. To add or modify the entries, you must access the
NAT Map Dialog Box by selecting the New or Modify buttons above the
External Range window.
PassThru Range Addresses
This is the address range which may pass through the external NAT port
without being translated. This is used when the NAT router has an IP inter-
face (or interfaces), in addition to the NAT internal port and NAT external
port, which is connected to part of the local network which is configured with
global IP addresses.
v Note: If an IP address or range of addresses is included in both the
External Range and PassThru Range, NAT will treat the IP address(es) as
being members of the External Range only.
This window displays a list of all entered PassThru Range but is not used to
add or modify the entries. To add or modify the entries, you must access the
NAT Map Dialog Box by selecting the New or Modify buttons next to the
PassThru Range window.