‘Reverse Proxy’ and ‘Load Balancer’ are two terms that are frequently used in the context of network architecture and web infrastructure. And, building reliable and scalable online applications requires an understanding of Reverse Proxy vs Load Balancer. Although they function as intermediary nodes in the client-server model similarly, they play different roles in network security and performance optimization.
Keep reading the article, as we will delve deep into the topic and comprehend Reverse Proxy vs Load Balancer, their respective types with use cases, and how they work in tandem to enhance the performance and security of your web infrastructure!
What Is a Reverse Proxy?
A reverse proxy server, frequently known as a reverse proxy, carries a key role in the ecosystem of web servers. Its function lies in serving as an intermediary tool or application strategically positioned between an end-user and a web server. In simple terms, it sits between client devices and a web server, delivering client requests to the appropriate web server and returning the server’s responses to the clients.
A reverse proxy works to improve the web servers, by preventing users from ever communicating directly with the origin server.
How Many Types of Reverse Proxies?
Reverse proxies are accessible in both hardware and software forms. Let’s see a number of popular open-source reverse proxy software options, including:
- Apache HTTP Server
- Apache Traffic Server
- HAProxy
- NGINX
- Pound
- Traefik
- Varnish HTTP Cache
Additionally, Web Application Firewalls (WAFs) are a particular kind of reverse proxy that is frequently used in business contexts. WAF maintains records of web traffic and defends a company’s web applications against online dangers like SQL injections, data theft, cross-site scripting, and other flaws. A Layer 7 load balancer is another type of reverse proxy, which we will discuss later.
How Does Reverse Proxy Work?
There are multiple important steps involved in using a proxy:
1. User Request: A user usually starts an HTTP request by typing the URL of a website into their web browser.
2. Request Reception: The reverse proxy receives and processes the user’s request by acting as a barrier between the user and the web server.
3. Request Validation: After reviewing the request, the reverse proxy decides whether to approve it or reject it. If rejected, the user is notified of an error or is redirected, if approved, the request moves on to the following phase.
4. Forwarding to Web Server: The reverse proxy forwards approved requests to the web server, which is usually located behind it.
5. Server Response: After that, the web server replies with the relevant information, frequently comprising website data.
6. Response Delivery: After receiving the response from the server, the reverse proxy sends it to the user to finish the transaction.
What Is a Load Balancer?
Another crucial element in the world of web infrastructure is a load balancer. Contrary to reverse proxies, load balancers act as an intermediary between users and collection servers rather than between users and individual web servers. The main purpose of load balancers is to reduce the load on heavily used servers, provide effective client request distribution, and maximize network speed and efficiency.
How Many Types of Load Balancers?
Load balancer can be divided into two main categories based on the digital system they employ and the particular Open Systems Interconnection (OSI) Model layer they function through.
Load Balancers by Digital System
1. Hardware Load Balancer Device: These actual objects are typically present in data centres. Usually, they work on the Transport Layer (L4) or Application Layer (L7).
2. Software Load Balancer (SLB): Software load balancers can be purchased as a service (LBaas) and installed on a server directly. They frequently appear as an application delivery controller (ADC) function.
Load Balancers by OSI Layer
1. Application Load Balancer (Level 7 Load Balancer or Reverse Proxy): This kind of load balancer works at Layer 7 of the OSI model, the highest layer. Based on application-level factors like URLs, HTTP headers, and SSL, it distributes web requests.
2. Gateway Load Balancer: A gateway load balancer works at Layer 3 (L3) and allows for simple scaling by directing all traffic through a single entry and exit point.
3. Global Server Load Balancer: This type of load balancer can connect to servers located worldwide and responds to user requests from the server that is closest to the requesting user.
4. Network Load Balancer (Level 4 Load Balancer): Operating at Layer 4 (L4), a network load balancer distributes traffic according to network variables including IP protocol, source IP, destination IP, and destination port.
How Does Load Balancer Work?
A load balancer operates as follows:
1. User Request: When anyone types any URL into their web browser, they are initiating a request, usually an HTTP request.
2. Request Reception: The load balancer receives and processes the user’s request and acts as a middleman between the user and several servers.
3. Server Selection: It chooses one server from many to handle the request.
4. Server Response: Now chosen server provides the relevant answer, which may contain information from the website.
5. Response Delivery: In order to complete the transaction, the load balancer forwards the server’s response to the user.
Reverse Proxy vs Load Balancer: Key Differences
1. Primary Function:
- Reverse Proxy – A reverse proxy’s main job is to operate as a middleman between clients and web servers, offering services like SSL termination, caching, and security.
- Load Balancer – Load balancers’s primary job is to split up incoming traffic among a number of servers or server clusters, ensuring even load distribution and high availability.
2. Layer of Operation:
- Reverse Proxy – Reverse proxy operates at the application layer (Layer 7) of the OSI model, where it places judgment on data particular to the application.
- Load Balancer – Manages server health and network traffic distribution by operating at both the transport layer (Layer 4) and the application layer (Layer 7).
3. Security and SSL:
- Reverse Proxy – Reverse proxy offers advanced security features like SSL termination, WAF, and DDoS defence.
- Load Balancer – Concentrates on traffic distribution and health monitoring but may not by default provide advanced security capabilities.
4: Caching and Content Optimization:
- Reverse Proxy – Enhances web application performance by providing content caching and optimization features.
- Load Balancer – Mainly responsible for traffic distribution and server health maintenance.
5: Session Persistence:
- Reverse Proxy – Although session persistence is not a standard feature of reverse proxies, it may be available as an option.
- Load Balancer – For an application that depends on session data maintained on the server, the load balancer frequently offers session persistence.
Conclusion
Finally, while both reverse proxy and load balancers are essential parts of network infrastructure, they play different roles in strengthening network security and maximizing web performance. Reverse proxies, such as Level 7 load balancers, concentrate on web requests and provide extra features, whereas load balancers are experts at effectively spreading user requests among a group of servers.
So, building and upholding a reliable and high-performing web infrastructure requires an awareness of the unique characteristics of these elements.
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