ZyWALL 70 Support Notes
All contents copyright (c) 2005 ZyXEL Communications Corporation.
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Using Dual WAN
This feature is for ZyWALL 35 & 70 only since ZyWALL 5 has only one WAN interface. There are two
operation modes for dual WAN. The “Active/Passive” is for fail-over and fall-back. And the
“Active/Active” is not only for fail-over and fall-back, but also can perform load balancing to make
outgoing traffic will be processed efficiently.
WAN backup (Active/Passive mode)
With ZyWALL’s Active/Passive mode, users can achieve backup of Internet connectivity, so when the
primary WAN (normally it’s lower-cost) is down, the secondary WAN (normally it’s higher-cost) can take
over the connectivity job.
This section describes how to use ZyWALL’s WAN backup feature to let ZyWALL’s Internet connectivity
always available including LAN users’ Internet access and DMZ servers’ availability.
Following is an example of a possible network topology. Company A has two Internet access methods, one is
ADSL, the other is ISDN. Since cost for ADSL is lower than ISDN, so the MIS decides to use ADSL for
general Internet Access and ISDN for backup.
Condition: ZyWALL gets one public IP address
