ZyXEL Communications P-660HN-F1A, User Manual

Page: 174 / 430

Chapter 9 Network Address Translation (NAT)
P-660HN-F1A User’s Guide
174
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.
SUA (Single User Account) Versus NAT
SUA (Single User Account) is a ZyNOS implementation of a subset of NAT that
supports two types of mapping,
Many-to-One
and
Server
. The P-660HN-F1A also
supports
Full Feature
NAT to map multiple global IP addresses to multiple private
LAN IP addresses of clients or servers using mapping types as outlined in Table 51
on page 187 .
• Choose SUA Only if you have just one public WAN IP address for your P-
660HN-F1A.
• Choose Full Feature if you have multiple public WAN IP addresses for your P-
660HN-F1A.
Finding Out More
See Section 9.6 on page 183 for advanced technical information on NAT.