What Is The Difference Between Nat And Sua; How Many Network Users Can The Sua/Nat Support; What Are Device Filters And Protocol Filters; Why Can't I Configure Device Filters Or Protocol Filters - ZyXEL Communications P-2302RL-P1 Support Notes

P2302RL-P1 Support Notes
original IP source address and TCP/UDP source port numbers are written into the destination fields of the
packet (since it is now moving in the opposite direction), the checksums are recomputed, and the packet is
delivered to its true destination. This is because SUA keeps a table of the IP addresses and port numbers of the
local systems currently using it.

What is the difference between NAT and SUA?

NAT is a generic name defined in RFC 1631 'The IP Network Address Translator (NAT)'. SUA (Internet
Single User Account) is ZyXEL's implementation and trade name for functioning PAT which is a specific type
of NAT. SUA (or PAT for NAT) translates address into port mapping.
The primary motivation for RFC 1631 is that there is not enough IP address to go around. In addition, many
corporations simply did not bother to obtain legal (globally unique) IP addresses for their networks and now
finding themselves unable to connect to the Internet.
Basically, NAT is a process of translating one address to another. A NAT implementation can be as simple as
substituting an IP address with another. This allows a network to rectify the illegal address problem mentioned
above without going through each and every host.
The design goal of ZyXEL's SUA is to minimize the Internet access cost in a small office environment by using
a single IP address to represent the multiple hosts inside. It does more than IP address translation, so that
multiple hosts on the LAN can access the Internet at the same time.

How many network users can the SUA/NAT support?

The ZyXEL Device does not limit the number of the users but the number of the sessions. The ZyXEL Device
supports 1024 sessions that you can use the 'ip nat iface enif0 disp' command in menu 24.8 to view the current
active sessions.

What are Device filters and Protocol filters?

In ZyNOS, the filters have been separated into two groups. One group is called 'device filter group', and the
other is called 'protocol filter group'. Generic filters belong to the 'device filter group', TCP/IP and IPX filters
belong to the 'protocol filter group'.

Why can't I configure device filters or protocol filters?

In ZyNOS, you can not mix different filter groups in the same filter set.
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