Problems with hierarchical caching

When we are a part of a cache hierarchy, we serve the content received from neighbors directly to our clients. So, there is a serious problem if content received from neighbors is not genuine. For example, let's say we are a part of a cache hierarchy and one of our neighbor proxy servers is compromised. In such a scenario, the compromised proxy server can serve any content for the requests we are forwarding. This generally leads to propagation of viruses and worms on a network. Therefore, all our neighbors should be properly secured and up-to-date so that we don't end up compromising our client for the sake of increasing our hit ratio.

We'll essentially be forwarding a lot of our client's requests to our neighbor proxy servers. This may result in leakage of private information of our clients. For example, a lot of data is sent as a part of the URL in HTTP GET requests. If a neighbor cache is not properly striping query terms from the URL before logging,...