Updated: Jan 31
Reverse proxies and load balancers are both parts that can be employed in normal system architecture. Both of these load balancers and reverse proxies act as a gateway for server-side communications and are placed between the client and server.
When a client sends a request, it believes that the server will get it, but in fact, the server's gateway receives the request. It is known as a reverse proxy because this server's gateway acts as a proxy to the original server and works to safeguard the data inside of it. Reverse proxies of a specific kind include load balancers.
A system may or may not have a reverse proxy or load balancer.
Let's dive right in -
What is a Reverse Proxy?
A reverse proxy is a type of proxy server that typically sits in the middle of a network. The reverse proxy acts as an intermediary between clients and one or more backend servers. It sends client requests to the appropriate backend server and then gives the client the server's response back.
The reverse proxy adds an extra layer of security and abstraction for the underlying servers by masking the identity of the backend servers. It is commonly used to offer security and caching. It can be described as a gateway between two networks, such as the Internet and an internal network. It can also be used to provide security and caching.
What is a Load Balancer?
A load balancer is a software or hardware solution that ensures that the load on each server is distributed evenly, resulting in increased performance. Load balancing improves the overall server's performance but it also comes with an increase in cost and complexity. Load balancing also has benefits for security and availability as it helps to balance out incoming requests for content across all servers.
Most load balancers are physical devices installed between the user and the server. The device then monitors the usage of each server and automatically redirects traffic depending on which one is least busy at any given time.
When Should I Use a Reverse Proxy?
A reverse proxy server is a type of proxy server that retrieves resources on behalf of a client from one or more servers. Reverse proxies are commonly used to retrieve web pages, images, and other content from web servers, and to provide caching services.
A reverse proxy can be used in various scenarios including:
To provide load balancing (Yes! load balancers is an application of a Reverse Proxy) in an architecture where multiple servers share the same IP address. It distributes incoming traffic among multiple backend servers to improve performance and availability.
To cache data that may be frequently accessed by clients, such as static files, images, videos, etc. It stores frequently-requested content to reduce the load on the backend servers and improve the response time for clients.
To provide access control and filtering of requests.
Provides security to the servers. It hides the identity of backend servers, providing an additional layer of protection against security threats. You can also build firewalls in a reverse proxy against common cyber attacks like the DDoS attack, SYN attack, etc.
SSL Pinning and starting and terminating the SSL protocol, handling SSL encryption and decryption, and offloading the processing load from the backend servers.
URL rewriting: modifying incoming URLs to improve usability or compatibility with backend servers.
When Should I Use a Load Balancer?
Load balancers are used to distribute workloads across multiple servers. They can be used to handle high volumes of requests, but they are also used as a security measure to protect the server. Load balancers also ease the process when you want to add servers to your system and you don't want to disrupt the clients.
The use of load balancers is often necessary when there is a sudden increase in traffic or workloads. Load balancers can also dynamically decide when to spawn a server base on the incoming traffic load. Load balancers will ensure that the load is distributed evenly across all available resources so that not all requests go unanswered and users get access to the website at all times.
To consolidate, some common uses of Load Balancers are:
Scalability: Load balancing helps distribute incoming traffic among multiple servers, allowing a network of servers to scale to handle increased demand.
High Availability: Load balancing helps ensure that the network of servers remains available even if one or more servers fail, by redirecting traffic to healthy servers.
Performance: Load balancing can improve the performance of a network of servers by distributing the load and reducing the risk of bottlenecks.
Security: Load balancing can provide an additional layer of security by hiding the identity of backend servers, making them less vulnerable to attacks.
SSL Termination: Load balancing can handle SSL encryption and decryption, offloading the processing load from the backend servers.
Content Caching: Load balancing can cache frequently-requested content to reduce the load on the backend servers and improve response times for clients.
URL Rewriting: Load balancing can modify incoming URLs to improve usability or compatibility with backend servers.
Since it distributes and manages the "load" on each server, we call it a load balancer. There are several types of load-balancing algorithms.
Hashing or Consistent Hashing: Routes the requests based on the hash of a pre-selected identifier.
Least Connections: Routes the request based on whichever server is the least occupied.
Least Response Time: Uses a combined formula of fastest response times and fewest active connections.
Power of Two Choices: To route the request, the load balancer will randomly choose two servers and then selects the server with the lowest active CPU utilization.
Round Robin: This will route the requests among the server in sequential order.
Conclusion - "Is the load balancer a reverse proxy?"
To answer the question - "Is the load balancer a reverse proxy?", the answer is yes. A load balancer is a special case of a reverse proxy. But in terms of a practical sense, the terms reverse proxy and load balancers are used to mean different things.
The term Reverse Proxy is used more in the context of computer networks or when an organization wants to set up its network infrastructure. Whereas the term load balancer is most commonly used in the context of designing distributed systems or architecting complex systems.
And that's a wrap! Hi, I am Gourav Dhar, a software developer and I write blogs on Backend Development and System Design. Subscribe to my Newsletter and learn something new every week - https://thegeekyminds.com/subscribe