After having recently discussed all the different kinds of proxies that exist, it occurred to me that it might be nice to provide some examples of what you can do with proxies besides the obvious web filtering scenario. This is by no means an exhaustive list, but is provided to show some of the more common (and cool, I think) uses of proxies.

What's really awesome is that while some of these uses are available with only one type of proxy (reverse or forward), a full proxy can provide all these uses, and more, in a single, unified application delivery platform.

1. DATA SCRUBBING

Data scrubbing is the process of removing sensitive information like credit card and social security numbers from web application responses. This is particularly useful in preventing data leaks, especially if you're subject to regulations like SOX, HIPPA, and PCI DSS where the penalties for divulging personally identifiable information can be harsh fines - or worse.

Data scrubbing is is an implementation of a reverse proxy.

2. URL REWRITING

Rewriting URLs is something everyone has likely had to do at one time or another if they've developed a web application. URL rewriting is used to refer web requests to new resources instead of sending out a redirect response in cases where resources have moved, renamed, or migrated to a new version.

URL rewriting is an implementation of a reverse proxy.

3. LAYER 7 SWITCHING

Layer 7 switching provides an organization with the ability to maximize their IP address space as well as architect a more efficient, better performing application architecture. Layer 7 switching routes specific web requests to different servers based on information in the application layer, like HTTP headers or application data.

Layer 7 switching is an implementation of a reverse proxy.

4. CONTENT FILTERING

The most common use of proxies is content filtering. Generally, content filtering allows or rejects requests for content based on organizational policies regarding content type, the existence of specific keywords, or based on the site itself.

Content filtering is an implementation of a forward proxy.

5. REDIRECTION 

Redirection is the process of, well, redirecting a browser to a new resource. This could be a new instance of a requested resource or as part of application logic such as redirecting a failed login to the proper page.

Redirection is generally implemented by a reverse proxy, but can also be implemented by a forward proxy as a means of redirecting rejected requests to an explanation page.

6. LOAD BALANCING 

Load balancing is one of the most common uses of a reverse proxy. Load balancing distributes requests for resources across a number of servers in order to provide scalability and availability services.

Load balancing is an implementation of a reverse proxy.

7. APPLICATION FIREWALL

An application firewall provides a number of functions including some in this list (data scrubbing and redirection). An application firewall sits in front of web applications and inspects requests for malicious content and attempts to circumvent security.

An application firewall is an implementation of a reverse proxy.

8. PROTOCOL SECURITY  

Protocol security is the ability of a proxy to enforce protocol specifications on requests and responses in order to provide additional security at all layers of the OSI stack. Protocol security provides an additional layer of security atop traditional security mechanisms that focus on data.

Protocol security is an implementation of a reverse proxy.