Reverse proxy servers and load balancers are both components in a client-server computing architecture. Both act as intermediaries in the communication between the clients and servers, performing functions that improve efficiency. They can be implemented as dedicated, purpose-built devices, but increasingly in modern web architectures they are software applications that run on commodity hardware. While they seem to perform similar functions, let’s explore when and why they’re typically deployed at a website.
A load balancer distributes incoming client requests among a group of servers to ensure satisfactory speed and optimized functioning. Load balancers are most commonly deployed when a site needs multiple servers because the volume of requests is too much for a single server to handle efficiently. Deploying multiple servers also eliminates a single point of failure, making the website more reliable. Most commonly, the servers all host the same content, and the load balancer’s job is to distribute the workload in a way that makes the best use of each server’s capacity, prevents overload on any server, and results in the fastest possible response to the client.
A reverse proxy accepts a request from a client, forwards it to a server that can fulfill it, and returns the server’s response to the client. Whereas deploying a load balancer makes sense only when you have multiple servers, it often makes sense to deploy a reverse proxy even with just one web server or application server. You can think of the reverse proxy as a website’s “public face.” Its address is the one advertised for the website, and it sits at the edge of the site’s network to accept requests from web browsers and mobile apps for the content hosted at the website. A reverse proxy provides an additional level of abstraction and control to ensure the smooth flow of network traffic between clients and servers. The reverse proxy provides:
- Increased security.No information about your backend servers is visible outside your internal network, so malicious clients cannot access them directly to exploit any vulnerabilities. Many reverse proxy servers include features that help protect backend servers from distributed denial-of-service (DDoS) attacks, for example, by rejecting traffic from particular client IP addresses (denylisting), or limiting the number of connections accepted from each client.
- Increased scalability and flexibility.Because clients see only the reverse proxy’s IP address, you are free to change the configuration of your backend infrastructure. This is particularly useful In a load-balanced environment, where you can scale the number of servers up and down to match fluctuations in traffic volume.
- Web acceleration. Reverse proxies can reduce the time it takes to generate a response and return it to the client to improve performance through such techniques as SSL acceleration,intelligent compressionand caching. Reverse proxies also enable federated security services for multiple applications by enforcing web application security.
