A reverse proxy server (or reverse proxy) facilitates a consumer’s requests to an internet server/utility server and the server’s response.
A load balancer receives consumer requests, distributes them accordingly amongst a gaggle of servers, then forwards every server response to its respective consumer.
From the transient definitions above, it’s clear that reverse proxies and cargo balancers have some overlapping functionalities.
For instance, they each act as middleman nodes that ahead requests and responses in a client-server mannequin.
Whereas they seem comparable at face worth, they’re two distinct items of structure with diverse roles in community safety.
This text unpacks the variations between reverse proxies and cargo balancers intimately to clear up any confusion between the pair.
What’s a Reverse Proxy Server?
A reverse proxy server is an middleman machine or utility between a consumer and an internet server. Reverse proxies are kind of proxy server designed to reinforce net servers’ safety by guaranteeing that customers by no means talk immediately with the origin server.
How Does a Reverse Proxy Work?
A typical reverse proxy operates as follows:
A consumer makes an HTTP request (through a firewall), e.g. enters an internet site’s URL into their net browser.The reverse proxy receives the consumer’s request.The reverse proxy both ‘allows’ or ‘denies’ the consumer’s request.If allowed, the reverse proxy forwards the request to the net server. If denied, it sends the consumer an error or redirect message. The online server sends a response (web site information) again to the reverse proxy.The reverse proxy forwards the server’s response to the consumer.
Reverse proxies obtain their title from the way in which they’re configured – in ‘reverse’ to a normal proxy server (or ahead proxy). Ahead proxies sit between a consumer and the Web, whereas reverse proxies sit between the community’s edge and the Web.
The opposing configurations of ahead and reverse proxies are depicted under.
Varieties of Reverse Proxies
Reverse proxies can be found in each {hardware} and software program varieties.
There are a lot of in style open-source reverse proxy software program options, corresponding to:
Internet Software Firewalls (WAFs) are a kind of reverse proxy, generally deployed in business use instances. A WAF screens net site visitors and protects a corporation’s net functions towards cyber assaults, corresponding to SQL injections, delicate information theft, cross-site scripting, and different vulnerabilities.
One other kind of reverse proxy is a Layer 7 load balancer. Layer 7 load balancers distribute net requests throughout a number of servers to enhance client-side community efficiency and consumer expertise.
Reverse Proxy Advantages
Whereas a reverse proxy’s major goal is to guard server-side operations, its performance gives advantages to each the shopper and server.
Enhanced SecurityThreat Safety: Because of their placement on the community’s edge, reverse proxies stop malicious purchasers from immediately accessing and exploiting any vulnerabilities inside a corporation’s inner community. Privateness: Reverse proxies conceal the origin server’s IP deal with for added information safety, stopping Web Service Suppliers (ISPs), net providers, and information facilities from monitoring their site visitors and doubtlessly inflicting information breaches.Filtering: Their potential to blacklist sure shopper IP addresses and restrict the variety of connections purchasers can provoke helps stop DDoS assaults.Load Balancing
Organizations can use a reverse proxy to distribute site visitors evenly and effectively throughout a number of backend servers.
Load balancing helps stop website shutdowns as site visitors will be rerouted to an alternate server (as a substitute of counting on one server) within the occasion of a community outage or DDoS assault.
Internet Acceleration
Reverse proxies allow sooner net server response instances, bettering website load instances and consumer expertise.
They use diverse net acceleration strategies to realize higher speeds.
Caching: Every time an internet server sends a response, reverse proxy shops a neighborhood copy of it. Subsequent time the consumer makes the identical request, the proxy can reply on to the consumer as a substitute of forwarding the request to the net server, lowering the response time and in addition assuaging the load on the server.Compression: Reverse proxies use compression algorithms to cut back the bandwidth required to ship the server’s response, rising site visitors pace. SSL/TLS Offloading – Reverse proxies can carry out SSL encryption and authentication on all incoming requests and responses.
As proxy acts because the endpoint to the SSL connection as a substitute of the net server, the net server can serve content material a lot sooner.
What’s a Load Balancer?
A load balancer acts as an middleman between a consumer and a gaggle of servers. Load balancers are used to alleviate pressure on high-traffic servers. They route shopper requests to essentially the most acceptable server, maximizing community pace and effectivity. By guaranteeing operational effectivity, load balancers assist organizations set up a scalable basis for his or her IT infrastructure.
How Does a Load Balancer Work?
Usually, a load balancer operates as follows:
A consumer makes a request, e.g. an HTTP request – getting into an internet site’s URL into their net browser.The load balancer receives the consumer’s request.The load balancer sends the request to a single server in a gaggle of various servers.The chosen server sends a response (web site information) again to the load balancer.The load balancer forwards the server’s response to the consumer.
Whereas the above instance explains how a load balancer handles net requests, load balancers can assist many different protocols, relying on their kind.
The way in which the load balancer selects which server to ahead a consumer’s request to will depend on which algorithm it makes use of.
Load Balancing Algorithms
A load balancing algorithm is a algorithm that determines which server is chosen inside a gaggle of various servers.
There are a number of forms of load balancing algorithms.
Hash: Selects a server primarily based on a predefined key, e.g. the shopper’s IP deal with. Least Connections: Sends requests to the server coping with the fewest current shopper connections.Least Response Time: Makes use of a mixed system of quickest response instances and fewest energetic connections.Energy of Two Decisions: Randomly chooses two servers then selects the server with the fewest energetic connections. Spherical Robin: Distributes requests throughout servers in a sequential method.s.Varieties of Load Balancers
Load balancers are categorized by which digital system they use and the precise layer of the Open Programs Interconnection (OSI) Mannequin by which they function.
Load Balancers by Digital SystemHardware Load Balancer System
{Hardware} load balancer gadgets are sometimes present in information facilities. They’re bodily gadgets that often function on the Transport Layer (L4) or Software Layer (Layer 7).
Software program Load Balancer (SLB)
Software program load balancers are purchasable as load balancer as a service (LBaaS), e.g., as a function of an utility supply controller (ADC), or will be put in immediately onto a server.
Load Balancers by OSI LayerApplication Load Balancer (Degree 7 Load Balancer or Reverse Proxy)
An utility load balancer operates on Layer 7 of the OSI mannequin – the very best layer.
It distributes net requests primarily based on application-level variables, corresponding to URLs, HTTP headers, and SSL.
A Layer 7 load balancer is a reverse proxy because it handles requests on the appliance stage – the layer by which HTTP operates.
Gateway Load Balancer
A gateway load balancer operates on Layer 3 (L3). As all site visitors flows by a single entry and exit level, enabling straightforward scalability.
World Server Load Balancer
A world server load balancer can hook up with servers all around the world. It responds to consumer requests from the server geographically closest to the requesting consumer.
Community Load Balancer (Degree 4 Load Balancer)
A community load balancer operates on layer 4 (L4).
It distributes site visitors primarily based on community variables, together with IP protocol, supply IP, supply port, vacation spot IP, and vacation spot port.
Load Balancer Advantages
A load balancer’s potential to distribute consumer requests effectively throughout a number of high-traffic servers gives many mutual advantages to the client-server mannequin.
Enhanced Person Expertise
Load balancers carry out well being checks to establish server outages after which reroute consumer site visitors to a functioning server.
They conduct well being checks by intercepting error response messages to the consumer or by sending direct requests to the server which require a selected response to sign the server is wholesome.
The load balancers’ intervention within the occasion of a server error signifies that customers expertise far fewer error messages and keep away from response lag.
Better Reliability
Load balancers are applied throughout multi-server deployments, guaranteeing requests are distributed evenly and effectively.
By stopping server overload and site visitors bottlenecks, load balancers present higher reliability to customers.
The supply of many servers as a substitute of a single server ensures consumer requests are nonetheless fulfilled, even within the occasion of an outage.
Session Persistence
As HTTP/S is a stateless protocol, session persistence is just not intuitive however is important for a lot of functions to carry out successfully.
For instance, net functions, corresponding to e-commerce websites, depend on session persistence to maintain buying baskets energetic.
Load balancers guarantee a selected consumer’s (i.e. from a selected IP deal with) requests are all the time despatched to the identical server throughout a session.
What’s the Distinction Between a Reverse Proxy and a Load Balancer?
Reverse proxies and cargo balancers each improve the efficiency of utility supply networks, however the roles they play on this optimization aren’t fairly the identical.
A reverse proxy is particularly a Degree 7 load balancer, dealing completely with net requests. A load balancer can function on Ranges 3-7 of the OSI mannequin, dealing with quite a few forms of requests on high of net requests, e.g., DNS, SSL, TCP.
A reverse proxy can carry out extra roles to that of a load balancer. For instance, a reverse proxy can even:
Function as a WAFPerform net acceleration, e.g. caching, TLS/SSL offloading, compressionProvide cybersecurity mechanisms, e.g. risk safety, IP concealment, net filtering
A load balancer’s major position is to distribute consumer requests throughout a number of servers. A reverse proxy can be utilized to facilitate requests between customers and a single server.
