Nat Technical Reference; Nat Definitions - ZyXEL Communications P-2900-4HB User Manual

Table 12 Edit Address Mapping Rule (continued)
LABEL
Apply
Cancel
Delete

6.3 NAT Technical Reference

This section provides some technical background information about the topics
covered in this chapter.

6.3.1 NAT Definitions

Inside/outside denotes where a host is located relative to the ZyXEL Device, for
example, the computers of your subscribers are the inside hosts, while the web
servers on the Internet are the outside hosts.
Global/local denotes the IP address of a host in a packet as the packet traverses a
router, for example, the local address refers to the IP address of a host when the
packet is in the local network, while the global address refers to the IP address of
the host when the same packet is traveling in the WAN side.
Note that inside/outside refers to the location of a host, while global/local refers to
the IP address of a host used in a packet. Thus, an inside local address (ILA) is the
IP address of an inside host in a packet when the packet is still in the local
network, while an inside global address (IGA) is the IP address of the same inside
host when the packet is on the WAN side. The following table summarizes this
information.
Table 13 NAT Definitions
ITEM
Inside
Outside
Local
Global
NAT never changes the IP address (either local or global) of an outside host.
P-2900-4HB User's Guide
DESCRIPTION
Click Apply to save your changes back to the ZyXEL Device.
Click Cancel to return to the previously saved settings.
Click Delete to exit this screen without saving.
DESCRIPTION
This refers to the host on the LAN.
This refers to the host on the WAN.
This refers to the packet address (source or destination) as the packet travels
on the LAN.
This refers to the packet address (source or destination) as the packet travels
on the WAN.
Chapter 6 Network Address Translation (NAT) Screens
63