What is a reverse proxy? | Proxy servers explained | Cloudflare
What is a reverse proxy?
A reverse proxy is a server that sits in front of web servers and forwards client (e. g. web browser) requests to those web servers. Reverse proxies are typically implemented to help increase security, performance, and reliability. In order to better understand how a reverse proxy works and the benefits it can provide, let’s first define what a proxy server is.
What’s a proxy server?
A forward proxy, often called a proxy, proxy server, or web proxy, is a server that sits in front of a group of client machines. When those computers make requests to sites and services on the Internet, the proxy server intercepts those requests and then communicates with web servers on behalf of those clients, like a middleman.
For example, let’s name 3 computers involved in a typical forward proxy communication:
A: This is a user’s home computer
B: This is a forward proxy server
C: This is a website’s origin server (where the website data is stored)
In a standard Internet communication, computer A would reach out directly to computer C, with the client sending requests to the origin server and the origin server responding to the client. When a forward proxy is in place, A will instead send requests to B, which will then forward the request to C. C will then send a response to B, which will forward the response back to A.
Why would anyone add this extra middleman to their Internet activity? There are a few reasons one might want to use a forward proxy:
To avoid state or institutional browsing restrictions – Some governments, schools, and other organizations use firewalls to give their users access to a limited version of the Internet. A forward proxy can be used to get around these restrictions, as they let the user connect to the proxy rather than directly to the sites they are visiting.
To block access to certain content – Conversely, proxies can also be set up to block a group of users from accessing certain sites. For example, a school network might be configured to connect to the web through a proxy which enables content filtering rules, refusing to forward responses from Facebook and other social media sites.
To protect their identity online – In some cases, regular Internet users simply desire increased anonymity online, but in other cases, Internet users live in places where the government can impose serious consequences to political dissidents. Criticizing the government in a web forum or on social media can lead to fines or imprisonment for these users. If one of these dissidents uses a forward proxy to connect to a website where they post politically sensitive comments, the IP address used to post the comments will be harder to trace back to the dissident. Only the IP address of the proxy server will be visible.
How is a reverse proxy different?
A reverse proxy is a server that sits in front of one or more web servers, intercepting requests from clients. This is different from a forward proxy, where the proxy sits in front of the clients. With a reverse proxy, when clients send requests to the origin server of a website, those requests are intercepted at the network edge by the reverse proxy server. The reverse proxy server will then send requests to and receive responses from the origin server.
The difference between a forward and reverse proxy is subtle but important. A simplified way to sum it up would be to say that a forward proxy sits in front of a client and ensures that no origin server ever communicates directly with that specific client. On the other hand, a reverse proxy sits in front of an origin server and ensures that no client ever communicates directly with that origin server.
Once again, let’s illustrate by naming the computers involved:
D: Any number of users’ home computers
E: This is a reverse proxy server
F: One or more origin servers
Typically all requests from D would go directly to F, and F would send responses directly to D. With a reverse proxy, all requests from D will go directly to E, and E will send its requests to and receive responses from F. E will then pass along the appropriate responses to D.
Below we outline some of the benefits of a reverse proxy:
Load balancing – A popular website that gets millions of users every day may not be able to handle all of its incoming site traffic with a single origin server. Instead, the site can be distributed among a pool of different servers, all handling requests for the same site. In this case, a reverse proxy can provide a load balancing solution which will distribute the incoming traffic evenly among the different servers to prevent any single server from becoming overloaded. In the event that a server fails completely, other servers can step up to handle the traffic.
Protection from attacks – With a reverse proxy in place, a web site or service never needs to reveal the IP address of their origin server(s). This makes it much harder for attackers to leverage a targeted attack against them, such as a DDoS attack. Instead the attackers will only be able to target the reverse proxy, such as Cloudflare’s CDN, which will have tighter security and more resources to fend off a cyber attack.
Global Server Load Balancing (GSLB) – In this form of load balancing, a website can be distributed on several servers around the globe and the reverse proxy will send clients to the server that’s geographically closest to them. This decreases the distances that requests and responses need to travel, minimizing load times.
Caching – A reverse proxy can also cache content, resulting in faster performance. For example, if a user in Paris visits a reverse-proxied website with web servers in Los Angeles, the user might actually connect to a local reverse proxy server in Paris, which will then have to communicate with an origin server in L. A. The proxy server can then cache (or temporarily save) the response data. Subsequent Parisian users who browse the site will then get the locally cached version from the Parisian reverse proxy server, resulting in much faster performance.
SSL encryption – Encrypting and decrypting SSL (or TLS) communications for each client can be computationally expensive for an origin server. A reverse proxy can be configured to decrypt all incoming requests and encrypt all outgoing responses, freeing up valuable resources on the origin server.
How to implement a reverse proxy
Some companies build their own reverse proxies, but this requires intensive software and hardware engineering resources, as well as a significant investment in physical hardware. One of the easiest and most cost-effective ways to reap all the benefits of a reverse proxy is by signing up for a CDN service. For example, the Cloudflare CDN provides all the performance and security features listed above, as well as many others.
What is a reverse proxy? | Proxy servers explained | Cloudflare
What is a reverse proxy?
A reverse proxy is a server that sits in front of web servers and forwards client (e. g. web browser) requests to those web servers. Reverse proxies are typically implemented to help increase security, performance, and reliability. In order to better understand how a reverse proxy works and the benefits it can provide, let’s first define what a proxy server is.
What’s a proxy server?
A forward proxy, often called a proxy, proxy server, or web proxy, is a server that sits in front of a group of client machines. When those computers make requests to sites and services on the Internet, the proxy server intercepts those requests and then communicates with web servers on behalf of those clients, like a middleman.
For example, let’s name 3 computers involved in a typical forward proxy communication:
A: This is a user’s home computer
B: This is a forward proxy server
C: This is a website’s origin server (where the website data is stored)
In a standard Internet communication, computer A would reach out directly to computer C, with the client sending requests to the origin server and the origin server responding to the client. When a forward proxy is in place, A will instead send requests to B, which will then forward the request to C. C will then send a response to B, which will forward the response back to A.
Why would anyone add this extra middleman to their Internet activity? There are a few reasons one might want to use a forward proxy:
To avoid state or institutional browsing restrictions – Some governments, schools, and other organizations use firewalls to give their users access to a limited version of the Internet. A forward proxy can be used to get around these restrictions, as they let the user connect to the proxy rather than directly to the sites they are visiting.
To block access to certain content – Conversely, proxies can also be set up to block a group of users from accessing certain sites. For example, a school network might be configured to connect to the web through a proxy which enables content filtering rules, refusing to forward responses from Facebook and other social media sites.
To protect their identity online – In some cases, regular Internet users simply desire increased anonymity online, but in other cases, Internet users live in places where the government can impose serious consequences to political dissidents. Criticizing the government in a web forum or on social media can lead to fines or imprisonment for these users. If one of these dissidents uses a forward proxy to connect to a website where they post politically sensitive comments, the IP address used to post the comments will be harder to trace back to the dissident. Only the IP address of the proxy server will be visible.
How is a reverse proxy different?
A reverse proxy is a server that sits in front of one or more web servers, intercepting requests from clients. This is different from a forward proxy, where the proxy sits in front of the clients. With a reverse proxy, when clients send requests to the origin server of a website, those requests are intercepted at the network edge by the reverse proxy server. The reverse proxy server will then send requests to and receive responses from the origin server.
The difference between a forward and reverse proxy is subtle but important. A simplified way to sum it up would be to say that a forward proxy sits in front of a client and ensures that no origin server ever communicates directly with that specific client. On the other hand, a reverse proxy sits in front of an origin server and ensures that no client ever communicates directly with that origin server.
Once again, let’s illustrate by naming the computers involved:
D: Any number of users’ home computers
E: This is a reverse proxy server
F: One or more origin servers
Typically all requests from D would go directly to F, and F would send responses directly to D. With a reverse proxy, all requests from D will go directly to E, and E will send its requests to and receive responses from F. E will then pass along the appropriate responses to D.
Below we outline some of the benefits of a reverse proxy:
Load balancing – A popular website that gets millions of users every day may not be able to handle all of its incoming site traffic with a single origin server. Instead, the site can be distributed among a pool of different servers, all handling requests for the same site. In this case, a reverse proxy can provide a load balancing solution which will distribute the incoming traffic evenly among the different servers to prevent any single server from becoming overloaded. In the event that a server fails completely, other servers can step up to handle the traffic.
Protection from attacks – With a reverse proxy in place, a web site or service never needs to reveal the IP address of their origin server(s). This makes it much harder for attackers to leverage a targeted attack against them, such as a DDoS attack. Instead the attackers will only be able to target the reverse proxy, such as Cloudflare’s CDN, which will have tighter security and more resources to fend off a cyber attack.
Global Server Load Balancing (GSLB) – In this form of load balancing, a website can be distributed on several servers around the globe and the reverse proxy will send clients to the server that’s geographically closest to them. This decreases the distances that requests and responses need to travel, minimizing load times.
Caching – A reverse proxy can also cache content, resulting in faster performance. For example, if a user in Paris visits a reverse-proxied website with web servers in Los Angeles, the user might actually connect to a local reverse proxy server in Paris, which will then have to communicate with an origin server in L. A. The proxy server can then cache (or temporarily save) the response data. Subsequent Parisian users who browse the site will then get the locally cached version from the Parisian reverse proxy server, resulting in much faster performance.
SSL encryption – Encrypting and decrypting SSL (or TLS) communications for each client can be computationally expensive for an origin server. A reverse proxy can be configured to decrypt all incoming requests and encrypt all outgoing responses, freeing up valuable resources on the origin server.
How to implement a reverse proxy
Some companies build their own reverse proxies, but this requires intensive software and hardware engineering resources, as well as a significant investment in physical hardware. One of the easiest and most cost-effective ways to reap all the benefits of a reverse proxy is by signing up for a CDN service. For example, the Cloudflare CDN provides all the performance and security features listed above, as well as many others.
Why use a reverse proxy? – Loadbalancer.org
Simply because – it offers high availability, flexible security, great performance, and easy maintenance. For businesses struggling with web congestion due to heavy usage, using a reverse proxy is the right solution. Reverse proxies help to keep web traffic flowing – seamlessly. Along with improving server efficiency and ease of maintenance, they also provide an important layer of additional cybersecurity. Using a reverse proxy is also a great way for businesses to consolidate their internet presence. Read our blog to find out more about exactly what a reverse proxy is. How a reverse proxy works In a computer network, a reverse proxy server acts as a middleman – communicating with the users so the users never interact directly with the origin servers. Serving as a gateway, it sits in front of one or more web servers and forwards client (web browser) requests to those web servers. Web traffic must pass through it before they forward a request to a server to be fulfilled and then return the server’s response.
A reverse proxy is like a website’s ‘public face. ‘ Its address is the one advertised on the website. It sits at the edge of the site’s network to accept web browsers and mobile apps requests for the content hosted at the website. Reverse proxies make different servers and services appear as one single unit, allowing organizations to hide several different servers behind the same name – making it easier to remove services, upgrade them, add new ones, or roll them back. As a result, the site visitor only sees and not Reverse proxies help increase performance, reliability, and security. They provide load balancing for web applications and APIs. They can offload services from applications to improve performance through SSL acceleration, caching, and intelligent compression. By enforcing web application security, a reverse proxy also enables federated security services for multiple applications. To sum up, reverse proxy servers can:
Conceal the characteristics and existence of origin servers
Ease out takedowns and malware removals
Carry TLS acceleration hardware, letting them perform TLS encryption in place of secure websites
Spread the load from incoming requests to each of the servers that supports its own application area
Layer web servers with basic HTTP access authentication
Work as web acceleration servers that can cache both dynamic and static content, thus reducing the load on origin servers
Perform multivariate testing and A/B testing without inserting JavaScript into pages
Compress content to optimize it and speed up loading times
Serve clients with dynamically generated pages bit by bit even when they are produced at once, allowing the pages and the program that generates them to be closed, releasing server resources during the transfer time
Assess incoming requests via a single public IP address, delivering them to multiple web-servers within the local area network
What are the key benefits of using a reverse proxy? Security, load balancing, and ease of maintenance are the three most important benefits of using reverse proxy. Besides, they can also play a role in identity branding and proved online securityReverse proxies play a key role in building a zero trust architecture for organizations – that secures sensitive business data and systems. They only forward requests that your organization wants to serve. If you’re only serving web content, you can configure your reverse proxy to exclude all requests other than those for ports 80 and 443 – the default ports responsible for HTTP and HTTPS. This helps divert traffic based on type. Reverse proxies also make sure no information about your backend servers is visible outside your internal network, thus protecting them from being directly accessed by malicious clients to exploit any vulnerabilities. They safeguard your backend servers from distributed denial-of-service (DDoS) attacks – by rejecting or blacklisting traffic from particular client IP addresses, or limiting the number of connections accepted from each organizations looking at deploying proxy servers with extra teeth, reverse proxies can be easily upgraded to a creased scalability and flexibilityIncreased scalability and flexibility, is generally most useful in a load balanced environment where the number of servers can be scaled up and down depending on the fluctuations in traffic volume. Because clients see only the reverse proxy’s IP address, the configuration of your backend infrastructure can be changed freely. When excessive amounts of internet traffic slow down systems, the load balancing technique distributes traffic over one or multiple servers to improve the overall performance. It also ensures that applications no longer have a single point of failure. If and when one server goes down, its siblings can take over! Reverse proxies can use a technique called round-robin DNS to direct requests through a rotating list of internal servers. But if businesses have more demanding requirements, they can swap to a sophisticated setup that incorporates advanced load balancing accelerationReverse proxies can also help with ‘web acceleration’ – reducing the time taken to generate a response and return it to the entity brandingMost businesses host their website’s content management system or shopping cart apps with an external service outside their own network. Instead of letting site visitors know that you’re sending them to a different URL for payment, businesses can conceal that detail using a reverse proxy.
Caching commonly-requested dataBusinesses that serve a lot of static content like images and videos can set up a reverse proxy to cache some of that content. This kind of caching relieves pressure on the internal services, thus speeding up performance and improving user experience – especially for sites that feature dynamic is a reverse proxy different from a forward proxy? Simply because a forward proxy server sits in front of users, stopping origin servers from directly communicating with that user and a reverse proxy server sits in front of web servers, and intercepts requests. While a forward proxy acts for the client, guarding their privacy, a reverse proxy acts on behalf of the server. Forward proxies are used to capture traffic from managed endpoints; however, they don’t capture traffic from unmanaged endpoints like reverse proxies do. Forward proxies are used not for load balancing, but for passing requests to the internet from private networks through a firewall and can act as cache servers to reduce outward verse proxy and load balancers: what’s the correlation? A reverse proxy is a layer 7 load balancer (or, vice versa) that operates at the highest level applicable and provides for deeper context on the Application Layer protocols such as HTTP. By using additional application awareness, a reverse proxy or layer 7 load balancer has the ability to make more complex and informed load balancing decisions on the content of the message – whether it’s to optimise and change the content (HTTP header manipulation, compression and encryption) and/or monitor the health of applications to ensure reliability and availability. On the other hand, layer 4 load balancers are FAST routers rather than application (reverse) proxies where the client effectively talks directly (transparently) to the backend servers. All modern load balancers are capable of doing both – layer 4 as well as layer 7 load balancing, by acting either as reverse proxies (layer 7 load balancers) or routers (layer 4 load balancers). An initial tier of layer 4 load balancers can distribute the inbound traffic across a second tier of layer 7 (proxy-based) load balancers. Splitting up the traffic allows the computationally complex work of the proxy load balancers to be spread across multiple nodes. Thus, the two-tiered model serves far greater volumes of traffic than would otherwise be possible and therefore, is a great option for load balancing object storage systems – the demand for which has significantly exploded in the recent years. What are the common reverse proxy servers? Hardware load balancers, open-source reverse proxies, and reverse proxy software – offered by many vendors on the market. However, HAProxy, released in 2001 by Willy Tarreau, is the best reverse proxy out there – we highly recommend it because it’s fast and free. Over the years, HAProxy has evolved significantly to meet the changing needs of modern applications. Therefore, today, it’s being widely used by countless organizations around the world. HAProxy calls out reverse proxies as a critical element in achieving modern application delivery. By offering key capabilities like routing, security, observability, and more, reverse proxies form the bridge from inflexible traditional infrastructure to dynamic, distributed environments. Click around our blogs for more on HAProxy, transparent proxy, load balancing web proxies, and loads more.
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Frequently Asked Questions about how reverse proxy server works
What is a reverse proxy and how it works?
A reverse proxy is a server that sits in front of one or more web servers, intercepting requests from clients. … With a reverse proxy, when clients send requests to the origin server of a website, those requests are intercepted at the network edge by the reverse proxy server.
Why do you need a reverse proxy?
Reverse proxies help increase performance, reliability, and security. They provide load balancing for web applications and APIs. They can offload services from applications to improve performance through SSL acceleration, caching, and intelligent compression.Jan 29, 2021
What is the difference between a proxy and a reverse proxy?
A traditional forward proxy server allows multiple clients to route traffic to an external network. … A reverse proxy, on the other hand, routes traffic on behalf of multiple servers. A reverse proxy effectively serves as a gateway between clients, users, and application servers.Mar 31, 2021