Deploying NetCache inside multiple firewalls

Goals when deploying NetCache inside multiple firewalls

When you deploy one or more NetCache appliances inside multiple firewalls, you want the following to occur:

Distribution of traffic over the firewalls
Failover of traffic to another firewall if one firewall goes down

Difference between transparent and nontransparent firewalls

If the firewall is transparent, routing automatically sends requests to the Internet. You do not need to configure NetCache for this to occur. However, if the firewall is nontransparent and running as a proxy, you must configure NetCache to distribute requests over the firewalls and have traffic fail over to the other firewall if one firewall goes down.

Example: NetCache inside parallel nontransparent firewalls

The following illustration shows a deployment with a NetCache appliance inside two parallel firewalls.

By defining (in the NetCache configuration) that the firewalls are part of a cluster in a logical hierarchy, you enable NetCache to distribute requests over the two firewalls. Otherwise, NetCache might use one firewall continually until it that firewall goes down and, only then, use the other firewall. See Section A, Request resolution hierarchies for an explanation of clusters.

Are there differences if there are multiple NetCache appliances?

No. A request is sent to one of the NetCache appliances, as determined by how the client traffic request distribution is set up. That NetCache appliance then interacts with the firewalls as described in this section. To make this deployment work, each NetCache appliance is configured with the same logical hierarchy configuration.