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@@ -802,3 +802,46 @@ Load balancers can also help with horizontal scaling, improving performance and
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* [Layer 4 load balancing](https://www.nginx.com/resources/glossary/layer-4-load-balancing/)
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* [Layer 7 load balancing](https://www.nginx.com/resources/glossary/layer-7-load-balancing/)
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* [ELB listener config](http://docs.aws.amazon.com/elasticloadbalancing/latest/classic/elb-listener-config.html)
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+
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+## Reverse proxy (web server)
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+
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+<p align="center">
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+ <img src="http://i.imgur.com/p7xHS4Z.png">
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+ <br/>
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+ <i><a href=https://commons.wikimedia.org/wiki/File:Proxy_concept_en.svg>Source: Wikipedia</a></i>
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+ <br/>
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+</p>
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+
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+A reverse proxy is a web server that centralizes internal services and provides unified interfaces to the public. Requests from clients are forwarded to a server that can fulfill it before the reverse proxy returns the server's response to the client.
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+
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+Additional benefits include:
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+
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+* **Increased security** - Hide information about backend servers, blacklist IPs, limit number of connections per client
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+* **Increased scalability and flexibility** - Clients only see the reverse proxy's IP, allowing you to scale servers or change their configuration
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+* **SSL termination** - Decrypt incoming requests and encrypt server responses so backend servers do not have to perform these potentially expensive operations
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+ * Removes the need to install [X.509 certificates](https://en.wikipedia.org/wiki/X.509) on each server
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+* **Compression** - Compress server responses
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+* **Caching** - Return the response for cached requests
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+* **Static content** - Serve static content directly
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+ * HTML/CSS/JS
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+ * Photos
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+ * Videos
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+ * Etc
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+
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+### Load balancer vs reverse proxy
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+
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+* Deploying a load balancer is useful when you have multiple servers. Often, load balancers route traffic to a set of servers serving the same function.
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+* Reverse proxies can be useful even with just one web server or application server, opening up the benefits described in the previous section.
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+* Solutions such as NGINX and HAProxy can support both layer 7 reverse proxying and load balancing.
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+
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+### Disadvantage(s): reverse proxy
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+
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+* Introducing a reverse proxy results in increased complexity.
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+* A single reverse proxy is a single point of failure, configuring multiple reverse proxies (ie a [failover](https://en.wikipedia.org/wiki/Failover)) further increases complexity.
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+
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+### Source(s) and further reading
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+
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+* [Reverse proxy vs load balancer](https://www.nginx.com/resources/glossary/reverse-proxy-vs-load-balancer/)
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+* [NGINX architecture](https://www.nginx.com/blog/inside-nginx-how-we-designed-for-performance-scale/)
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+* [HAProxy architecture guide](http://www.haproxy.org/download/1.2/doc/architecture.txt)
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+* [Wikipedia](https://en.wikipedia.org/wiki/Reverse_proxy)
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Donne Martin