Glossary https://www.litespeedtech.com/images/logos/litespeed/litespeed-logo.png 2019-09-05 21:16:55 Defining industry-standard terminology for web application delivery such as web server, load balancing, cache plugins, control panels, web acceleration, cluster and so on.

Glossary

Defining industry-standard terminology for web application delivery.

What is .htaccess?

.htaccess (aka Hypertext Access) is a directory-level configuration file used by Apache web server (and Apache-compatible servers, like LiteSpeed).

.htaccess defines the configuration of the server, and enables or disables additional functionality. An .htaccess file can be simple, containing basic redirects and rewrite rules, or complex with advanced functions such as password protection, cache control, and image hot link prevention.

The scope of .htaccess is the directory in which it appears.

.htaccess support with LiteSpeed

What is Anti-DDoS?

DDoS is short for Distributed Denial of Service. During a DDoS attack, perpetrators use a large number of IP addresses to flood the server with incoming traffic. These attacks can be volume-based, protocol-based, or application-layer-based.

Anti-DDoS is a collective term for the strategies used to battle the variety of DDoS attack techniques. Typically, Anti-DDoS tools mitigate the impact of DDoS attacks on networks through firewalls, and a variety of harware and software solutions.

LiteSpeed's Anti-DDoS Solutions

What is Apache Web Server?

Apache Web Server is free, open-source, cross-platform web server software. It played a key role in the initial growth of the internet, which is a contributing factor to its continuing popularity since 1996. Typically, Apache runs on Linux, though Windows is also supported. Apache's relatively slow process-based model has been improved upon in recent decades by the event-driven alternatives from companies like LiteSpeed and Nginx.

Easily Replace Apache with LiteSpeed

What is Application Delivery?

Typically, application delivery is a web-based service, through which data is processed and computed in a cloud environment or data center, and then executed through application clients to end users over the internet. Functionality is meant to be quick and efficient.

In the past, application delivery was restricted to hardware solutions, but nowadays you can find software based Application Delivery Controllers (or, ADCs). These software ADCs bring optimization by automating the deployment of additional ADCs as required. Enterprises may use ADCs to create highly scalable models which provide load balancing, security, and a more reliable user experience.


What is an Application Delivery Network?

An Application Delivery Network (or, ADN) is similar to the more familiar Content Delivery Network (CDN), however CDNs focus on static content, while ADNs handle dynamic content. Both CDNs and ADNs exist for the purpose of optimizing content delivery. At the data center end of an ADN is the Application Delivery Controller (ADC). ADNs feature performance-maximizing technologies that, when deployed together, provide availability, security, visibility, and acceleration to clients.


What is an Application Delivery Controller (ADC)?

An Application Delivery Controller (or ADC) is a network device in a data center, and is often part of an Application Delivery Network (ADN). ADCs are used to enhance performance through measures that include load balancing, caching, compression, and offloading of SSL processing. In a data center, ADCs are often placed between the firewall and one or more application servers, in an area known as the DMZ.

Learn about the LiteSpeed's Web ADC

What is an Application Server vs. a Web Server?

Often the terms Application Server and Web Server are used interchangeably, though they are not the same thing. The biggest difference between them is that a web server handles HTTP requests and is meant for static content, while an application server executes business logic using any number of protocols (including, sometimes, HTTP) and is suitable for dynamic content. Most application servers have a web server integrated into them, which means that an application server is capable of any function that a web server is capable of, and then some.

Application servers support Connection Pooling, Object Pooling, Transaction Support, Messaging services, and more. Most production environments use a web server as reverse proxy to the application server. This allows static content to be served quickly by the web server, while the app server handles the dynamic portion of the request.


What is Caching?

Simply put, caching temporarily stores a snapshot of recently-used information so that the snapshot may be re-used. This saves the system from repeatedly generating the same information. It improves efficiency, shortens data access times, reduces latency and improves system performance. Users are able to access the information more quickly, leading to an improved user experience.

Learn about LiteSpeed Cache

What is a Cache Plugin?

A cache plugin is add-on software for a web application that facilitates the caching of static HTML pages generated by the web app. Via the cache plugin, an web app is able to serve up static HTML upon user request, instead of forcing the user to wait for the content to be dynamically generated.

See LiteSpeed's available Cache Plugins

What is a Certification Authority (CA)?

A Certification Authority (also called a Certificate Authority or CA) issues digital certificates, which serve as the subject's proof of ownership for a public key. CA's act as a trusted third party, and conducts digital certificate signing securely through HTTPS.


What is a Certificate Signing Request (CSR)?

When an applicant wishes to apply for a digital identity certifican from a certificate authority, a certificate signing request (CSR) is one of their first steps. A CSR is generated on the server where the certificate will be installed, and contains such information as the organization name, domain name, city, region and country. Also included is a public key, which is an encoded block of text that is given to the CA as part of the application. With the creation of the CSR a private key is created as well. The public key and private key together are known as a key pair.


What is a CDN?

A CDN, or Content Delivery Network, is a cluster of geographically distributed servers, intended to optimize the delivery of web content to user. Geographically, the closer a CDN server is to a user, the faster the content delivery will be. Additionally, some CDN services are helpful at relieving large surges in traffic and mitigating DDoS attacks.

Learn about QUIC.cloud CDN, currently in beta

What is Cloud Hosting?

Cloud hosting refers to a type of server configuration. The simplest example of cloud hosting is a network of virtual servers that tap into an underlying network of physical servers. This setup results in a scalable, reliable, and affordable hosting solution.

Learn how to get LiteSpeed in the cloud

What is Clustering?

Clustering is achieved by placing a load balancer in front of multiple computers (aka nodes) so that they appear to be a single virtual machine to clients. The load balancer accepts client requests and distributes them to the nodes in a manner that keeps any one node from being too much busier than any other.

Clustering provides an easily-scalable, as you can easily add more servers to meet increased demand. It is a cost-effective hardware solution for improving a website or application's performance and reliability.

Clustering may be configured in multiple ways, the simplest being Round Robin. In this setup, requests are distributed sequentially across the nodes in the cluster. Other clustering configurations implement Layer 7 load balancing where different types of specialized machines can direct traffic to the appropriate server based on the type of content requested. For example, requests for video may be routed to a streaming media server, while requests for shop prices or inventory may be sent to a database application.

It's relatively easy to maintain a clustered environment, even during business hours. Nodes in a clustered environment can be taken offline for service and upgraded as needed, while the remaining nodes service user requests.

Learn about LiteSpeed's clustering software solution

What is cPanel?

cPanel is a popular Linux-based hosting control panel. The web interface allows users to quickly and easily configure many web server and account settings.

A tiered structure facilitates the use of cPanel by users at varying levels, from administrator to end user, and gives each user access to only the settings revelant to his or her role. This setup makes it simple for users to manage their own hosting with minimal technical knowledge.

Learn about LiteSpeed's cPanel plugin

What is DNS Load Balancing?

Domain Name System (DNS) Load Balancing is a server configuration by which DNS request are distributed across the servers. This creates a highly available, well-performing DNS infrastructure.

Under this system DNS servers are monitored and removed from service if failure is detected. All servers are behind a single external IP, and so DNS servers can be removed for maintenance at any time, without affecting current requests. Similarly, servers may be added dynamically when needed.


What is ESI?

The main purpose of Edge Side Includes (ESI) is to address the problem of web infrastructure scaling. It allows the transparent management of online content across application servers, content management systems (CMS) and content delivery networks (CDN). It's a simple markup language originally proposed by Akamai, Oracle and a group of other companies.

ESI allows an application to set apart sections of a page, and offload the processing of those sections from the application to an edge server. ESI is designed to resolve caching issues that are caused by frequently-changing content, such as that found in catalogs, forums, login pages or other personalized content. With ESI, an uncacheable portion can be split off into a separate request, while the larger portion of the page can be cached. Allowing most of the page to remain cached results in lower costs and faster load time, and it helps to relieve server load during high volume traffic spikes.

Learn about LiteSpeed's ESI support

What is an Event-Driven Architecture?

In an event-driven framework, a server employs one process (or very few processes) to handle all events that pop up — new requests coming in and new dynamic responses ready to go out. The server concerns itself not with creating new processes to handle every aspect of every connection, but with reacting to events that occur. This is faster and consumes significantly less CPU and memory than a process-based server, which requires a new process to be created for each request.

A web server built with an event-driven architecture fields a request and forwards it to an external process. Then, instead of waiting around for a dynamic response, it continues to field more requests. When an external process response is ready, the server gets a callback. The event-driven server then sends the external response back to the requesting client.

Learn about LiteSpeed's Event-Driven Architecture

What is a Full Page Cache?

A Full Page Cache is a type of caching whereby dynamically-generated content is stored as a static HTML snapshot and served in response to user requests, until the static file expires. This method helps to boost the performance of websites by eliminating the need to dynamically generate pages on every visit.

Learn about LiteSpeed's full page cache plugins

What is High Availability?

High availability (HA) refers to systems that have a long uptime. An HA configuration provides a failover setup for multiple nodes. When one node is temporarily unavailable, other notes will automatically detect and take over their traffic. HA systems are durable and likely to operate continuously without failing for long duration.

Learn about HA for LiteSpeed Web ADC

What is HTTP?

HTTP stands for "HyperText Transfer Protocol." It is a stateless protocol which defines how messages are formatted and transmitted, and what actions web servers and browsers should take in response to various commands.

HTTP was developed by Tim Berners-Lee at CERN in 1989, and has become the foundation of data communication for the World Wide Web.


What is HTTP/2?

In 2015, the Internet Engineering Task Force (IETF) defined a major revision of the HTTP network protocol used by the World Wide Web. This revision is referred to as HTTP/2, and was derived from the Google's experimental SPDY protocol. It is not a ground-up rewrite of the original HTTP. Methods, status codes and semantics remain the same, and it should be possible to use the same APIs with either protocol.

HTTP2's focus is on performance, specifically end-user perceived latency, and network/server resource usage.

Learn about LiteSpeed's HTTP/2 Implementation

What is HTTP/3?

HTTP/3 is the proposed third version of the Hypertext Transfer Protocol (HTTP), which is used to exchange binary information on the World Wide Web. In November 2018, the first successful HTTP/3 interoperability test was performed by LiteSpeed Technologies and Facebook, but the protocol is still experimental. As of mid-2019, The IETF is still defining what HTTP/3 will look like.

HTTP/3 builds on UDP, unlike previous HTTP versions which are TCP-based, and aims to solve constraints within the existing internet infrastructure.

Learn about LiteSpeed's HTTP/3 Implementation

What is HTTPS?

Hypertext Transfer Protocol Secure (HTTPS) is an extension of HTTP using Transport Layer Security (TLS) encryption. It is sometimes referred to as HTTP over TLS, or HTTP over SSL. It is widely used for secure Internet communication.

The main purpose of HTTPS is authentication and privacy protection while data is in transit. It guards against man-in-the-middle attacks. The bidirectional encryption of communications between a client and server protects against eavesdropping and tampering.

HTTPS is now used more often by web users than the original non-secure HTTP.

More Info

What is Load Balancing?

Load balancing is a key component that acts as reverse proxy to distribute application traffic across a number of servers. Load balancers increase performance, load capacity, and reliability.

Layer 7 load balancers make complex and informed load balancing decisions at the application level. There are several industry standard load balancing algorithms, including Round Robin, Weighted Round Robin, Least Connections, and Least Response Time.

Learn about LiteSpeed's Load Balancer

What is LiteSpeed QUIC Client Library?

LiteSpeed QUIC Client Library is an open-source implementation of QUIC functionality for clients, and contains all of the code necessary to build a custom QUIC client to interact with QUIC servers. Released in the interest of speeding the adoption of QUIC, most of the code in the distribution is used in LiteSpeed's own web server and ADC products.

QUIC stands for Quick UDP Internet Connections. This is an experimental transport layer network protocol which is designed to provide security protection equivalent to TLS/SSL. QUIC helps to reduce connection establishment time and improve congestion control. QUIC is used to solve the problem of high RTT by reducing the number of trips that must be taken, in which HTTP/2 and SPDY failed to resolve previously. QUIC uses UDP (User Datagram Protocol) instead of ubiquitous TCP. QUIC uses UDP protocol over ports 80 and 443. This permits clients to bypass transparent proxies and also suggest that forwarding proxies can also be bypassed.

Learn about LiteSpeed QUIC Client Library

What is LiteSpeed Technologies?

LiteSpeed Technologies Inc was founded in 2002 by George Wang. It is an information technology company based in New Jersey, USA that produces leading high-performance, high-scalability web server software designed specifically for high-traffic servers, such as those of Internet service providers and corporate data centers.

It's flagship product, LiteSpeed Web Server, can be used to replace an existing Apache server without changing any other programs or operating system details, and without breaking anything. As such, LiteSpeed Web Server can quickly replace a major bottleneck in your existing web hosting platform. With its comprehensive range of features and easy-to-use web administration console, LiteSpeed Web Server can help you conquer the challenges of deploying an effective web hosting infrastructure.


What is LiteSpeed Web ADC?

LiteSpeed Web ADC (LSLB - previously LiteSpeed Load Balancer) is an affordable, high-performance layer 7 HTTP smart load-balancing application. LiteSpeed Web ADC is feature-rich, secure, and efficient, offering more flexibility than similarly-priced load balancing software. This makes it an excellent choice for small enterprises looking to scale their applications beyond one server — both to improve service speed as well as reliability in case of hardware failure.

Learn more about LiteSpeed Web ADC

What is LiteSpeed Web Server?

LiteSpeed Web Server (LSWS) is compatible with commonly used Apache features including mod_rewrite, .htaccess, and mod_security.

As a drop-in Apache alternative, LSWS can load Apache configuration files directly and can fully integrate with popular control panels. Replacing Apache with LSWS takes less than 15 minutes with zero downtime.

Unlike other solutions that act as frontend proxies, LSWS replaces all Apache functions, simplifying use and making the transition to a new server easy for your team. Move confidently forward with little-to-no retraining.

Learn more about LiteSpeed Web Server

What is a Managed VPS Hosting?

A managed VPS is a server that is installed, configured, secured, updated, and audited by an expert. Users get the benefit of a VPS without needing to bother with day-to-day maintenance and other management details.

Typically managed VPS hosting packages include:

  • 24x7 expert technical support
  • Data backups on remote servers
  • Guaranteed uptime
  • An easy-to-use control panel that allows one to start/stop/restart the VPS
  • VPS installation and initial setup
  • Solid VPS server security
  • Daily updates and security monitoring
  • Malware scans and removal

What is MIME-type?

A media type (known as a Multipurpose Internet Mail Extensions or MIME type) is a two-part identifier for file formats and format contents transmitted on the Interne. Designed mainly for SMTP, the content types defined by MIME standards are also of importance in communication protocols outside of email, such as HTTP for the World Wide Web.

Servers insert the MIME header at the beginning of any web transmission. Clients use this header to select an appropriate viewer application for the type of data the header indicates.


What is ModSecurity?

ModSecurity is an open-source Apache module specifically designed to protect websites from malicious activity. It's a web application firewall (WAF), requiring a group of customizable rulesets and triggers, in order to achieve real-time web application monitoring, logging, and access control.

Learn about LiteSpeed and ModSecurity

What is OpenLiteSpeed?

OpenLiteSpeed is the Open Source edition of LiteSpeed Web Server Enterprise.

Both servers are actively developed and maintained by the same team, and are held to the same high-quality coding standard.

OpenLiteSpeed contains all of the essential features found in LiteSpeed Enterprise, and represents our commitment to support the Open Source community.

Learn about OpenLiteSpeed

What is OpenSSL?

OpenSSL is widely used by internet servers to secure communications over networks. The majority of HTTPS websites use OpenSSL, which contains an open-source implementation of the SSL and TLS protocols. Its core library is written in the C programming language. OpenSSL executes basic cryptographic functions and provides various utility functions. Wrappers are available in a variety of computer languages, allowing for widespread use of the OpenSSL library.


What is Private Cache?

A private cache is a cache that is accessed by a single client at a single IP address. A separate, personalized copy of a privately cached page is stored for each user who requests it. Private caches are helpful for data that cannot or should not be shared publicly, such as personalized greetings and shopping cart contents.


What is Public Cache?

A public cache is a cache that can be accessed by everyone. A single copy of a publicly cached page is stored and served to everyone who requests it. Public cache is ideal for sites that do not require a login, or do not display sensitive or personalized information.


What is reCAPTCHA?

reCAPTCHA is a security feature, meant to determine that a user is human before granting access to a submission form, web page, application, or even an entire server. At the server level, reCAPTCHA is an effective Anti-DDoS measure.

Hundreds of millions of CAPTCHAs are solved by people every day. reCAPTCHA makes positive use of this human effort by channeling the time spent solving CAPTCHAs into annotating images and building machine learning datasets. This in turn helps improve maps and solve hard AI problems.

Learn more about LiteSpeed's reCAPTCHA

What is Reseller Hosting?

Reseller hosting is a form of web hosting where the account owner uses allocated hard drive space and bandwidth to host websites on behalf of third parties. Typical web hosting resellers include web design firms, web developers, and marketing agencies who offer web hosting as an add-on service. Most reseller hosting plans allow resellers to create their own branding via customized control panels and service plans, and allow them to choose their own pricing structure.


What is a Reverse Proxy Server?

A reverse proxy is a server that sits in front of one or more web servers, intercepting requests from clients. When clients send requests to the origin server of a website, those requests are intercepted at the network edge by the reverse proxy server. The reverse proxy server will then send requests to and receive responses from the origin server. A reverse proxy provides an additional level of abstraction and control to ensure the smooth flow of network traffic between clients and servers. It ensures that no client ever communicates directly with that origin server.

Common uses for a reverse proxy server include:

  • Load Balancing
  • Caching
  • Web acceleration
  • Protection from attacks
  • SSL encryption

What is a Reverse Proxy vs. a Load Balancer?

A reverse proxy server and load balancer have very similar features. Often, they are promoted together as a load balancer/reverse proxy combination, and all of the features are built into one bundle. A load balancer refers to a server or a device that balances inbound requests across two or more web servers to even the load. A reverse proxy server typically includes load balancing capabilities but also boasts additional features, like caching, security, and SSL acceleration.


What are Rewrite Rules?

Rewrite rules or mod_rewrite is an Apache web server extension for flexible url rewriting. It uses a rule-based rewriting engine, based on a PCRE regular-expression parser, to rewrite requested URLs on the fly. mod_rewrite's main function is to map a URL to a file system path. It can also be used to redirect one URL to another URL or to invoke an internal proxy fetch.

mod_rewrite can have an unlimited number of rules, and each rule can attach an unlimited number of rule conditions. This allows a URL to be rewritten on the basis of server variables, environment variables, HTTP headers, or time stamps. mod_rewrite may be invoked in httpd.conf or in .htaccess.


What is Round-Robin Load Balancing?

This is one of the most simplistic methods for distributing client requests across a number of servers. Round Robin forwards a client request to each server in turn, and loops back to the beginning of the server list, once it reaches the end.

The main benefit of Round Robin load balancing is that it is very easy to implement. However, since it assumes all servers are the same, it does not always result in the most accurate or efficient distribution of traffic. Because of this, two variations exist:

  • Weighted Round Robin — A weight is assigned to each server based on the criterion of the traffic handling capacity by an site administrator. The higher the weight, the larger volume of client requests the server receives.
  • Dynamic Round Robin — A weight is assigned to each server dynamically, based on real-time data of server load and idle capacity.

What are Server Side Includes (SSI)?

Server Side Includes (SSI) are codes you can add to your HTML document that tell the web server to include other content with the document being served. They let you add dynamically generated content to an existing HTML page, without having to serve the entire page dynamically.

HTML documents with SSI directives should be saved with the .shtml, .stm or .shtm file extensions.


What is Session Persistence?

In load balancing, session persistence ensures that a client's requests go to the same, single backend server for the duration of that session. This is also referred to as a "sticky session". Additionally, session persistence can refer to the feature that forces multiple client requests of the same protocol to be directed to the same node. This is common with many web applications that do not inherently share application state between back-end servers. The implemented logic ties a user session to a specific server for as long as necessary.


What is Shared Hosting?

Companies that offer shared hosting allow customers to utilize and share a single server. Each customer generally has a limited amount of server resources available to them, as defined by the hosting package. While the server resources are shared, customers are unable to access each others' data on the server. Since accounts on shared hosting don't have direct access to the server, maintenance is handled by the hosting provider.

Shared hosting tends to be the most economical hosting option, however, the cheap price comes with limitations. It is common for busy websites to outgrow shared hosting, and in this case, hosting companies usually offer upgrades to dedicated hosting packages.

Find a Shared Hosting Provider who offers LiteSpeed

What is a Subrequest?

A subrequest looks like a normal request, but shares some data with its parent. The request is processed as usual, but without the overhead of sending a full HTTP request over the network. Subrequests are primarily used to insert output of one request into another, possibly mixed with other data.


What is Transport Layer Security (TLS)?

Transport Layer Security (TLS) is a protocol that provides authentication, privacy, and data integrity between two communicating applications. It's the most widely-deployed security protocol today and is used for web browsers and other applications that require data to be securely exchanged over a network, such as web browsing sessions, file transfers, VPN connections, remote desktop sessions, and voice over IP (VoIP).

What is Web Acceleration?

The term "web acceleration" refers to the activity of increasing website and application performance. It utilizes variety of techniques such as caching and compression, in order to speed up the transfer of content between web servers and client browsers.

Learn more about how LiteSpeed accelerates the Internet