ZyXEL Communications P-660RU-Tx User Manual page 90

Chapter 10 Network Address Translation (NAT)
NAT
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 global address) back to the
inside local address before forwarding it to the original inside host.
Port Forwarding
A port forwarding set is a list of inside (behind NAT on the LAN) servers, for
example, web or FTP, that you can make visible to the outside world even though
NAT makes your whole inside network appear as a single computer to the outside
world.
Single IP Versus NAT
Single IP is a ZyNOS implementation of a subset of NAT that supports two types of
mapping, Many-to-One and Server. The P-660RU-Tx also supports multiple IPs
to map multiple public IP addresses to multiple private LAN IP addresses of clients
or servers using mapping types.
• Choose Single IP if you have just one public WAN IP address for your P-660RU-
Tx.
• Choose Multiple IPs if you have multiple public WAN IP addresses for your P-
660RU-Tx.
Finding Out More
See Section 10.6 on page 97
90
for advanced technical information on NAT.
P-660RU-Tx User's Guide