Load Balancer vs Reverse Proxy

 

Why to use a Reverse Proxy ?

What is the difference between Load Balancer and Reverse Proxy? SO

When you refer to a load balancer you are referring to a very specific thing – a server or device that balances inbound requests across two or more web servers to spread the load.
Link Load Balancer does – load balancing, service discovery, health checks, Sticky sessions, TLS termination, Observability, Security and DoS mitigation.

A reverse proxy, however, typically has any number of features:

1. load balancing
2. caching: it can cache content from the web server(s) behind it and thereby reduce the load on the web server(s) and return some static content back to the requester without having to get the data from the web server(s)
3. security: it can protect the web server(s) by preventing direct access from the internet; it might do this through simple means by just obfuscating the web server(s) or it may have some more active components that actually review inbound requests looking for malicious code
4. SSL acceleration: when SSL is used; it may serve as a termination point for those SSL sessions so that the workload of dealing with the encryption is offloaded from the web server(s)
5. connection pooling (allow multiple requests on one frontend connection when backend doesn’t handle it well; or reuse backend connection for multiple frontend connections)
6. Some load balancers balance traffic using DNS, resolving the same name to different IPs in a round robin effectively redirecting requests. This can often be useful when load balancing requests between data centers or other physical locations. This is a poor choice if you need “instant” fail over, as you’re at the mercy of your clients DNS server to honor the TTL you’ve provided. Cisco’s GSS (Global Site Selector) is a good example of DNS based load balancing.
   A reverse proxy works by accepting the request on behalf of the web server then echoing that request to the web server and returning it to the client, optionally caching the results should a similar request follow.

7. A load balancer can balance traffic from layer 3 upwards to layer 7, but a reverse proxy is HTTP specific. Load balancers however can deal with a lot of other protocols.