ZyXEL Communications LTE6100, Руководство пользователя

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Chapter 8 Network Address Translation (NAT)
LTE6100 User’s Guide
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The following table describes the fields in this screen.
8.5 Technical Reference
This section provides some technical background information about the topics covered in this
chapter.
8.5.1 NAT Definitions
Inside/outside denotes where a host is located relative to the LTE 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.
NAT never changes the IP address (either local or global) of an outside host.
8.5.2 What NAT Does
In the simplest form, NAT changes the source IP address in a packet received from a subscriber
(the inside local address) to another (the inside global address) before forwarding the packet to the
WAN side. When the response comes back, NAT translates the destination address (the inside
Table 24
Network Setting > NAT > Sessions
LABEL DESCRIPTION
MAX NAT
Session Use this field to set a common limit to the number of concurrent NAT sessions each client
computer can have.
If only a few clients use peer to peer applications, you can raise this number to improve
their performance. With heavy peer to peer application use, lower this number to ensure no
single client uses too many of the available NAT sessions.
Apply Click Apply to save your changes.
Cancel Click Cancel to restore your previously saved settings.
Table 25
NAT Definitions
ITEM DESCRIPTION
Inside This refers to the host on the LAN.
Outside This refers to the host on the WAN.
Local This refers to the packet address (source or destination) as the packet travels on the LAN.
Global This refers to the packet address (source or destination) as the packet travels on the WAN.