Network Address And Port Translation (Napt) Or; Port Address Translation (Pat) - Asus SL1200 User Manual

Chapter 9 - Configuring Firewall/NAT Settings

9.2.3 Network Address and Port Translation (NAPT) or

Port Address Translation (PAT)

This mapping is also called IP Masquerading. This maps many internal
hosts to one globally valid Internet address. The mapping contains a pool
of network ports to be used for translation. Every packet is translated with
the globally valid Internet address and the port number is translated with
an available port from the pool of network ports. Figure 9.4 shows that all
the hosts on the local network gain access to the Internet by mapping to
only one globally valid IP address and different port numbers from a free
pool of network ports.
Figure 9.4 NAPT – Map Any Internal PCs to a Single Global IP Address
Figure 9.5 Reverse Static NAT – Map Figure 9.6 Reverse NAPT – Relayed
a Global IP Address to An Internal Incoming Packets to the Internal
PC Host Base on the Protocol, Port
Number or IP Address
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ASUS SL1200