NetCache interaction with a firewall

If NetCache is outside a firewall

If you are deploying a NetCache appliance outside a firewall, no further configuration is required to enable NetCache to access the Internet. However, you might want to ensure that clients and caches outside your organization cannot use this cache to resolve requests, thereby using your bandwidth. See Hierarchies for more information about configuring access controls to prevent access by other proxy-cache servers. See the access controls chapter in the Security Guide for information about how to create access controls for clients.

If NetCache is deployed inside a transparent firewall

If NetCache is deployed inside a transparent firewall, no explicit NetCache configuration is required. NetCache uses the default gateway to send requests to the Internet. However, the firewall must be configured to accept requests from NetCache and forward them to the Internet.

If NetCache is deployed inside a nontransparent firewall

If NetCache is deployed inside a nontransparent firewall, you must configure a request resolution hierarchy, with the nontransparent firewall as a member of the hierarchy. The reason is that a NetCache appliance that exists inside a nontransparent firewall has no way to send requests through the firewall to the Internet. When the firewall is configured as a hierarchy member, NetCache can route unresolved requests to the firewall for routing to the Internet.

You can specify the domains and IP addresses that are local to the NetCache appliance so that NetCache can bypass the hierarchy for requests for local origin servers. Bypassing the hierarchy for origin servers that exist physically near your NetCache appliance can speed performance and reduce the load on parent and neighbor caches.