Cisco Cisco Email Security Appliance X1070 Troubleshooting Guide

Contributed by Jai Gill and Robert Sherwin, Cisco TAC Engineers.
Aug 07, 2014

This document describes the prerequisties and requirements needed for configuring clustering on the Email
Security Appliance (ESA).  

Valid Centralized Management feature key on each ESA that you wish to join into a cluster.

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Starting with AsyncOS 8.5.6, the feature key is no longer required to enable Centralized Management
feature. By default, Centralized Management feature is enabled on your appliance.

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The centralized management feature allows you to manage and configure multiple appliances at the same
time, reducing administration time and ensuring a consistent configuration across your network. You do not
need to purchase additional hardware for managing multiple appliances. The centralized management feature
provides increased reliability, flexibility, and scalability within your network, allowing you to manage
globally while complying with local policies.

A cluster is defined as a set of machines that share configuration information. Within the cluster, machines
(Cisco appliances) are divided into groups; every cluster will contain at least one group. A given machine is a
member of one and only one group. An administrator user can configure different elements of the system on a
cluster−wide, group−wide, or per−machine basis, enabling the segmentation of Cisco appliances based on
network, geography, business unit, or other logical relationships.

Note: Clustering is not used to load balance or route mail between ESAs.  Clustering does not share queue or
quarantines between ESAs.

Clusters are implemented as a peer−to−peer architecture; there is no master/slave relationship within a cluster.
You may log into any machine to control and administer the cluster.