ZyXEL Communications 1000 User Manual

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Chapter 6 Configuration Basics
ZyWALL USG 1000 User’s Guide
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6.4  Packet Flow
Here is the order in which the ZyWALL applies its features and checks.
Figure 64   Packet Flow
6.4.1  ZLD 2.20 Packet Flow Enhancements
ZLD version 2.20 has been enhanced to simplify configuration. The packet flow 
has been changed as follows:
• Automatic SNAT and WAN trunk routing for traffic going from internal to 
external interfaces (you don’t need to configure anything to all LAN to WAN or 
WLAN to WAN traffic). 
The ZyWALL automatically adds all of the external interfaces to the default WAN 
trunk. External interfaces include ppp, cellular, and aux interfaces as well as any 
Ethernet interfaces that are set as external interfaces. 
Examples of internal interfaces are WLAN interfaces and any Ethernet interfaces 
that you configure as internal interfaces.
• A policy route can be automatically disabled if the next-hop is dead.
• You do not need to set up policy routes for IPSec traffic.
• Policy routes can override direct routes.