L39
Forward proxies, reverse proxies and filtering
Cram this first — memory hook
Forward = for the clients; reverse = reception for the servers.
Exam trap
A reverse proxy, load balancer and Content Delivery Network can have overlapping features without being identical concepts.
The slide facts
A forward proxy helps clients reach external services; a reverse proxy fronts servers. Proxies may filter, log, cache or terminate Transport Layer Security , depending on configuration.
If you have time — extra
A forward proxy acts on behalf of clients: a school sends outbound web requests through it for policy and logging. A reverse proxy acts on behalf of servers: outside clients connect to it and it forwards requests to appropriate internal applications. Think assistant making calls for employees versus receptionist receiving calls for a department. A transparent/intercepting proxy can be placed in the path without explicit per-client proxy settings; a non-transparent/explicit proxy is configured as a proxy by the client. Content filtering may use a Uniform Resource Locator (), content type or reputation. A reverse proxy can terminate Transport Layer Security (), but the onward connection must be protected separately if needed. A proxy does not automatically decrypt all traffic, hide every identity or prevent every attack.
Walkthrough
Identify whom the proxy represents, trace client → proxy → destination, identify where authentication/encryption occur on each leg, then apply the required filtering and access policy.