Is Layer 4 load balancer a reverse proxy?

Are load balancers proxy servers?

I'm using load balancers.

I have a VPS with 1 public IP address and I use 2 load balancers for the 2 web servers behind it.

Do I need to be worried about the load balancer caching the requests to my web servers? If I use a load balancer as a proxy server, do I need to worry about the cache being used? Yes, you should be concerned. When a load balancer caches the response, then when a user sends a request to a different IP address (eg, from another computer), the load balancer will return the cached response. Then that same user will continue to get the cached response instead of sending a new request to the server with the new IP address.

You can avoid this by ensuring that all users are directed to the IP address of the server they are connected to (eg, if you have 2 load balancers and each receives traffic from 50 users, you want to direct them all to a single server). You also need to ensure that the load balancer is configured to pass along any errors back to the client, otherwise the user won't know that the load balancer isn't returning the response.

Is Azure load balancer a reverse proxy?

Azure load balancer seems like a reverse proxy.

What's the difference between load balancer and proxy? Does load balancer acts as proxy? No, Azure load balancer is not a reverse proxy, and it is definitely not a reverse proxy in the classic sense. However, there are certain cases where using load balancer (rather than an external reverse proxy) will help improve performance: High number of concurrent HTTP requests. By proxying your traffic, the load balancer can limit the number of backend instances in the service to one instance (the frontend) and still be able to handle a high number of requests.

High-throughput HTTP traffic. Since a lot of the traffic is usually not latency sensitive, you don't need to cache anything, so a load balancer will help you scale better.

Traffic pattern which fits a load balancing model. You can use a reverse proxy like F5 to do a lot of things with HTTP traffic, but if that traffic is not latency sensitive, then a load balancer like Azure may better suited for you.

Load balancer is a type of network load-balancer (LB) that distributes incoming network connections across multiple web servers, load balancers, or other Internet hosts. A reverse proxy is a type of load-balancer that performs request redirection and request caching. Reverse proxies are load-balancers for other computers and applications (web servers, applications, databases, etc.) When you use a reverse proxy, you forward requests to a back-end service or application without any modification to the request message itself (method, path, body, etc. Azure Load Balancer does not require you to define a static set of rules or rulesets for when it should redirect and cache a request. For example, you can't direct all SSL traffic to your S3. This is because SSL is only supported by a subset of the Microsoft Azure Network Load Balancing rules. For more information about which rules support SSL, see Supported security protocols.

Is Layer 4 load balancer a reverse proxy?

If the application under load balancer works fine without a problem, can I be sure that server under load balancer doesn't get overloaded?

If not, can someone guide me on how should I verify if the server gets overloaded? Does ntop/puppeteer provides an out of box way to capture server requests? What are the best practices of verifying a client request from servers under load balancer? Thanks. I haven't yet read any documents/papers on how best to do this. But in case you get stuck reading on that one day, and/or want to know how to do it yourself, you can look here. It will probably take about 10 minutes to implement (you don't have to write any java/javascript etc).

You could then use a tool like nload or tcpdump to see what the requests are like and whether they're too much for your machine, but there are many other ways to see whether things are good or not. For instance, you could log out requests using a tool like loggly and see if their usage goes up after a minute. You could have the user enter any username/password for that purpose - then you would know what sort of load the server is getting.