ZyXEL Communications 3.1 User Manual

ZyWALL (ZLD) CLI Reference Guide

Use device HA to increase network reliability. Device HA lets a backup ZyWALL (B) automatically 
take over if a master ZyWALL (A) fails.  

Device HA Backup Taking Over for the Master

• Active-passive mode lets a backup ZyWALL take over if the master ZyWALL fails. 
• Legacy mode uses VRRP (Virtual Router Redundancy Protocol) groups and allows for more 

complex relationships between the master and backup ZyWALLs, such as active-active or using 
different ZyWALLs as the master ZyWALL for individual interfaces. Legacy mode configuration 
involves a greater degree of complexity. Active-passive mode is recommended for general 
failover deployments.

• The ZyWALLs must all support and be set to use the same device HA mode (either active-passive 

or legacy). 

You can configure a separate management IP address for each interface. You can use it to access 
the ZyWALL for management whether the ZyWALL is the master or a backup. The management IP 
address should be in the same subnet as the interface IP address. 

Use synchronization to have a backup ZyWALL copy the master ZyWALL’s configuration, signatures 
(anti-virus, IDP/application patrol, and system protect), and certificates.

Note: Only ZyWALLs of the same model and firmware version can synchronize.

A

B