Standard request distribution

About default forwarding

NetCache forwards unresolved outbound requests based on the information entered when the hierarchy is configured. Default settings can be enabled on the Hierarchies - General page in the Appliance Manager (Setup tab > Hierarchies > General). The NetCache default settings for distributing outbound requests are highly efficient, and most organizations do not require custom settings. For example, you can enable default hierarchy forwarding rules to send

Requests for local servers or the local domain directly to local servers
Requests for noncacheable objects directly to origin servers
Protocol-specific requests to hierarchy members that support the same protocol
The NetCache hierarchy feature supports default forwarding rules for handling HTTP, FTP, FTP over HTTP, Gopher, Tunnel (HTTPS), MMS, and RTSP protocol requests.

Note
If you are configuring a hierarchy for a Web cache, all hierarchy members handling transparent FTP must be NetCache appliances.

Distribution methods

Distribution methods are settings that control how NetCache forwards unresolved requests. You define the distribution method when you create a forwarding rule on the Hierarchies - Forwarding Rules page (Setup tab > Hierarchies > Forwarding Rules).

NetCache can be configured to distribute unresolved requests in one of the following ways:

Direct--Send requests directly to the origin server, a local domain, or an origin server on the Internet. The NetCache appliance does not send a request through another proxy-cache server or firewall. This method of distribution requires the NetCache appliance to have direct connectivity to the Internet.
Single host--Send requests to a specified proxy-cache server or firewall.
Parent cluster or firewall cluster--Load balance requests over multiple parents or multiple firewalls that handle the same protocol.
ICP (Internet Cache Protocol)--Query other cache hosts within the hierarchy for individual Web pages. ICP is always used for communicating with neighbors.

Direct monitor

Direct monitor is a basic hierarchy setting on the Setup > Hierarchy > General page that enables NetCache to monitor Internet connectivity by establishing TCP connections with each host specified. When attempts to connect to all hosts fail, the Internet connection is considered down and NetCache fails over to the next forwarding rule for directing requests. Failover can be enabled or disabled on a per-rule basis. See Custom settings to support failover for more information.

Note
To designate a direct path to the Internet that supersedes host defined connections, you must create a hierarchy forwarding rule to identify and set the distribution method for a particular host to "direct."