Zyxel P-791R v2 Рекомендации по настройке онлайн [7/98] 154425

P-791R v2 Support Notes

9. What is SUA? When should I use SUA?

SUA (Single User Account) is a unique feature supported by P-791R v2 router

which allows multiple people to access Internet concurrently for the cost of a

single user account.

When P-791R v2 acts as SUA receives a packet from a local client destined

for the outside Internet, it replaces the source address in the IP packet header

with its own address and the source port in the TCP or UDP header with

another value chosen out of a local pool. It then recomputes the appropriate

header checksums and forwards the packet to the Internet as if it is originated

from P-791R v2 using the IP address assigned by ISP. When reply packets

from the external Internet are received by P-791R v2, the 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.

10. What is the difference between SUA and Full Feature NAT?

When you edit NAT in Web Configurator, Advanced Setup, Network -> NAT

-> General, there will be three options for you:

z Inactive NAT

z SUA Only

z Full Feature

SUA (Single User Account) in previous ZyNOS versions is a NAT set with 2

rules: Many-to-One and Server. With SUA, 'visible' servers had to be mapped

to different ports, since the servers share only one global IP.

The P-791R v2 now has Full Feature NAT which supports five types of IP/Port

mapping: One to One, Many to One, Many to Many Overload, Many to Many

No Overload and Server. You can make special application when you select

Full Feature NAT. For example: With multiple global IP addresses, multiple

severs using the same port (e.g., FTP servers using port 21/20) are allowed on

the LAN for outside access.

You can edit Full Feature NAT in Network->NAT->Address Mapping