ZyXEL Communications Prestige 2302RL Support Notes page 44

TCP/IP filters are applied before SUA address translation on outgoing traffic to the WAN and after SUA
address translation on incoming traffic from the WAN. This allows the Prestige to apply the filters with the
specified IP address and port number accurately before SUA.
Generic filters are applied at the point of transmission. For example when the traffic is received or transmitted
on an interface.
Figure1 shows the filter logic flow sequence. Steps of the logic flow sequence for LAN-to-WAN traffic are
listed below.

LAN device and protocol input filter sets.

WAN protocol call and output filter sets.

If SUA is enabled, SUA changes the source IP address from 192.168.1.33 to 203.205.115.6 and
port number from 1023 to 4034.

WAN device output and call filter sets.
Steps of the logic flow sequence for WAN-to-LAN traffic are listed below.
 WAN device input filter sets.

If SUA is enabled, SUA changes the destination IP address from 203.205.115.6 to 92.168.1.33 and port
number from 4034 to 1023.

WAN protocol input filter sets.

LAN device and protocol output filter sets.
All contents copyright (c) 2007 ZyXEL Communications Corporation.
Prestige 2302RL Support Notes
44