About upstream proxies
After configuring upstream proxy settings, you can use a single upstream proxy for all web requests.
Multiple upstream proxies
There are three potential destinations for a web request forwarded to an upstream proxy. These are as follows, in order of precedence:
- A pool of one or more proxies allowed by the upstream proxy policies, to service the request.
- The default proxy, if configured.
- Direct forwarding of requests to their origin servers, if allowed. An origin server is defined as the target destination of web request, in other words, the server from which a requested resource originates.
Upstream proxy policies are additive. The Smoothwall Filter checks requests against all the policies, in order. Any proxy allowed to service a request is added to the proxy pool. If the final pool for a request contains two or more proxies, load-balancing and fail-over rules decide the one that sent the request.
Note: The rules only apply to requests serviced by the Smoothwall Filter. If a device behind the Filter can obtain direct, unfiltered web access, the client’s requests are treated no differently from other Internet traffic.