and will be handled outside the regular release schedule. There are a lot of companies offering Varnish hosting and services and I was not planning to maintain a comprehensive directory of them all here. The problem seems to be when one of these files is requested (maybe by older browsers) and it's not already in the Varnish cache. Why do jet engine igniters require huge voltages? In addition to this, paying customers also get access to other components in the Varnish Plus product, and support from Varnish Software engineers. 2-4 months after the corresponding VC release, while maintainence Varnish has been used for high-profile and high-traffic websites, including Wikipedia, The Guardian, and The New York Times. does paying down principal change monthly payments? (Varnish Plus only). This documentation is not a replacement for other resources where basic Varnish concepts are explained. For a cache hit, X-Varnish will contain both the ID of the current request and the ID of the request that populated the cache. request rate throttling, and advanced cache invalidation with softpurge and Varnish Cache is a reverse proxy for caching HTTP, also sometimes known as an HTTP accelerator. This is the administrator and developer manual for Varnish Cache Plus. with timeouts, calendar and accounting functions for paywalls/metered access. The problem seems to be when one of these files is requested (maybe by older browsers) and it's not already in the Varnish cache. So, Varnish cache or caching HTTP reverse proxy is basically a web application accelerator. xkey. 1 Corinthians 3:15 What does "escaping through the flames" convey? Getting started with Varnish Cache sets you firmly on a path to a high performing website with practical information and tips. how to install, configure and update Varnish Cache Plus, features available in Varnish Cache Plus and its related packages, how to tune Varnish Cache Plus for better performance, how to extend its capabilities through the use of Varnish Modules. Why is the expense ratio of an index fund sometimes higher than its equivalent ETF? varnishadm Our site has a number of large PDF and MP3 files which we would like to cache in Varnish as static files. This maintenance release is recommended for all users of the 6.0 LTS and contains several bug fixes, improvements and new features. What are Hermitian conjugates in this context? What is Varnish cache? releases follow closer after their corresponding Varnish Cache releases. Other Varnish Plus components may package other VMODs that are documented The cache is often the most critical piece of software for a web-based business. Cisco Patient Connect 1.6 Admin View Guide. Get familiar with Varnish VCL (Configuration Language), caching principles and become an expert in all things Varnish with this manual. any server that speaks HTTP and configure it to cache the contents. 1.1.1 Varnish is Flexible 21 1.2 Varnish Cache and Varnish Plus 22 1.3 Varnish Cache and Varnish Software Timeline 24 1.4 What Is New in Varnish 4? It only takes a minute to sign up. Smallest known counterexamples to Hedetniemi’s conjecture. Varnish with separate auth check or auth check followed by Varnish? “Varnish is a “Web application accelerator also known as a caching HTTP reverse proxy” – according to Varnish’s official website. There is also a Varnish 3.0.2 release with baked in "full" streaming support available: http://repo.varnish-cache.org/test/3.0.2+streaming/ which people are using in production, so maybe you want to give it a try. This website uses cookies Our website, platform and/or any sub domains use cookies to understand how you use our services, and to improve both your experience and our marketing relevance. Varnish is a HTTP/web page accelerator. Varnish is a program that can increase the speed of a Web site while simultaneously reducing the load on the Web server. What is Varnish Cache? What's the word for someone who takes a conceited stance in stead of their bosses in order to appear important? Linkedin has a varnish topic and a Varnish Cache Group. Right now Varnish Software is focusing on developing Varnish Cache There are a lot of companies offering Varnish hosting and services and I was not planning to maintain a comprehensive directory of them all here. Asking for help, clarification, or responding to other answers. and Ubuntu package repositories. Varnish can be that … More about Varnish cache. WPBase Cache; The plugin was developed to optimize the WordPress deployment on varnish + nginx + php-fpm + php-apc server stack using three type of caches full page cache, db cache and opcode cache. Design Principles. The Varnish Book is really the comprehensive, nitty-gritty technical “bible” for all things Varnish Cache and Varnish Solutions. Before getting much into the error, let’s first discuss the Varnish cache in brief. I tried it with server sent events where I need streaming first request and cached second request. To learn more, see our tips on writing great answers. In my old company on patch day we used a script to curl the most visited URLs to have them in cache before bringing the server online again. How to Use Varnish to Speed up my Website¶. rev 2021.1.18.38333, The best answers are voted up and rise to the top, Server Fault works best with JavaScript enabled, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company, Learn more about hiring developers or posting ads with us. Varnish Cache and Varnish Plus; Varnish Cache and Varnish Software Timeline; What is new in Varnish 4? We use Varnish both as a load balancer and to speed up page loads by having varnish answer requests, instead of storage servers (which answer slower). Once you HTTP (curl) client interface, memcached client, IP geolocation, hash Varnish Cache is really, really fast. It's designed as an HTTP accelerator and can act as a reverse proxy for your web server (Apache or Nginx). Varnish Cache. are not ordered by default. Our site has a number of large PDF and MP3 files which we would like to cache in Varnish as static files. Therefore, a lot of what RFC2616 has to say about caches do not apply to Varnish Cache. Let’s end this guide by looking at some of the useful programs that the Varnish Cache distribution comes with. There is a delay while Varnish downloads the file from the backend. Using Varnish Cache’s domain-specific language, Varnish Cache Configuration Language (VCL), users can cache both static and so-called … Dynamic backend support, runtime ACL creation, fast hash table support There are also several paid services which provide Varnish Cache as a service or hosted versions of Varnish, What is the "Ultimate Book of The Master". T his guide helps you master Varnish basics so you can get up and running in no time - without the steep learning curve. All software related to Varnish Cache Plus and modules is available in Redhat Experience shows that companies forget to tell when they go out of business, move, change names or drop products, and therefore such lists either takes a lot of effort or end up having negative utility. This list is not meant to be complete, but as a pointer to what is available. functionality of Varnish. https://www.varnish-software.com/blog/http-streaming-varnish, http://repo.varnish-cache.org/test/3.0.2+streaming/, Podcast 305: What does it mean to be a “senior” software engineer. Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. It uses Varnish – a HTTP/web page accelerator, both as a load balancer and to speed up page loads. What language(s) implements function return value by assigning to the function name. It is most often used to cache content in front of the web server - anything from static images and CSS files to full HTML documents can be cached by Varnish Cache. PDF - Complete Book (1.35 MB) PDF - This Chapter (205.0 KB) … Improves cache hit rate. It typically speeds up delivery with a factor of 300 - 1000x, depending on your architecture. functions (digest) functionality. For example is the Varnish Cache Plus 4.1.2r1 release based on Varnish Cache How long the files are cached in memory depends on your varnish/memory setup. ipcast (3.0) Varnish Cache is an HTTP accelerator and reverse proxy developed by Danish consultant and ... (which is available to read online or as a downloadable PDF). Varnish Cache provides a high-performance cache layer that can be used to accelerate the read performance of NetApp StorageGRID storage software. Because Symfony’s cache uses the standard HTTP cache headers, the Symfony Reverse Proxy can be replaced with any other reverse proxy. X . This document explains how to install Varnish Reverse Proxy for LibreNMS. Varnish Cache is a powerful, open source HTTP engine/reverse HTTP proxy that can speed up a website by up to 1000 percent by doing exactly what its name implies: caching (or storing) a copy of a webpage the first time a user visits. The 3.0.2+streaming branch is not up-to-date anymore and it is only supported for Varnish Plus subscribers, no community support on that. It acts more like a middle man between your client (i.e. Book Title. Varnish Distribution; Exercise: Install Varnish; Exercise: Configure Varnish. Varnish Installation Guide. Why did flying boats in the '30s and '40s have a longer range than land based aircraft? Twitter is a good place to reach us out. Varnish is also discussed in a number of social media. Varnish cache increases the speed of a Website but takes up space on the device such as a computer, smartphone or tablet. elsewhere. Varnish is caching software that sits logically between an HTTP client and an HTTP server. Currently we don't do much special - simply remove the cookies in vcl_recv and set resetp.ttl = 100w; in vcl_fetch. Varnish Cache is really, really fast. The main audiences for this manual are systems administrators and managers looking into Varnish Plus for solving their caching needs and users that need to look up information on various Varnish Plus components. How to limit the disruption caused by students not writing required information on their exam until time is up, How to make one wide tileable, vertical redstone in minecraft. Varnish Cache Plus is a special version of Varnish Cache made by Varnish Software for paying customers. Here are the solutions to some of the most common Varnish cache issues including how to clear varnish cache server and other problems. any server that speaks HTTP and configure it to cache the contents. Varnish is a powerful, open-source, HTTP accelerator capable of serving cached content fast and … Test and see if the upcoming Varnish Cache 4.0 (release expected in Q2 2014) solves this issue for you (it should). Should varnish sess_con = cache_hit + cache_hitpass + cache_miss? user) and your web server. It just works. Troubleshooting¶ If Varnish fails to start, try running it from the command line as follows: varnishd … Server Fault is a question and answer site for system and network administrators. Is there a way to both pass the content directly while download and save it in the cache for the next matching client request? For this we refer to The Varnish Book or other introductions to Varnish and VCL. Or maybe you could "prewarm" your files, placing them in the Varnish memory cache before users start downloading it? It’s not a stand-alone solution, because it needs a dedicated web server to rely on, like NGINX or Apache. Varnish Cache Plus contains a set of Varnish Modules (VMODs) that extends the The logo is provided in EPS and PDF formats which is ideally suited for printing on paper, cloth, banner, etc. It more of an extension of the web-server, which is probably best thought of as “a webserver that picks up its contents with HTTP”. This again depends on the actual Varnish server settings. To get started with Varnish-Cache we recommend that you read the installation guide Varnish Installation. VMODs from the varnish-modules_ package, including cookie handling, header 2020-11-06 - Varnish 6.0.7 is released¶ We are happy to announce the release of Varnish Cache 6.0.7. The varnish is a program that is capable of increasing the speed of a website and reducing the load on the web server simultaneously. It is most often used to cache content in front of the web server - anything from static images and CSS files to full HTML documents can be cached by Varnish Cache. Which is warmer for slipper socks—wool or acrylic? The expected release cycle of a major Varnish Cache Plus release is By default, along with other cached contents, the Varnish Cache holds onto 404 responses. It works on the concept of HTTP caching. Plus 6.0.x, which builds on what is currently known as the stable 15. customer-specific token. More information is available in the Change log Varnish Cache. Chapter Title. Our site has a number of large PDF and MP3 files which we would like to cache in Varnish as static files. Reading suggestion: https://www.varnish-software.com/blog/http-streaming-varnish. 1000 cache hits @ 100 Mbit/sec: Sample Min Max Median Average Stddev Full 12,9 3001 16,2 71,1 338,5 90% fractile 12,8 26 15,9 16,3 1,7 (all times are in … Among other things, it contains the information on. Fast sorting of request arguments for applications where GET arguments These repositories are available on https://packagecloud.io using a functionality in 4.0 and newer. The problem seems to be when one of these files is requested (maybe by older browsers) and it's not already in the Varnish cache. version of Varnish Cache. Varnish Cache is a reverse proxy for caching HTTP, also sometimes known as an HTTP accelerator. Normally it should be enough to just request the files (e.g. Sometimes it is useful to temporarily disable the varnish cache, for example when editing your website. Only needed in Varnish 3.0, builtin Varnish is fast! Did "Antifa in Portland" issue an "anonymous tip" in Nov that John E. Sullivan be “locked out” of their circles because he is "agent provocateur"? We also don’t want to make this information free, because if we did, every criminal and his brother would sign up, to get a head start against the Varnish users. The logo is provided in EPS and PDF formats which is ideally suited for printing on paper, cloth, banner, etc. Varnish Cache is a popular tool due to how quickly it delivers content from the cache and how flexible it can be. Cisco Patient Connect 1.6 Admin View Guide. Varnish acts as a cache HTTP reverse proxy and sometimes you can also see it defined as a front-end accelerator. Match a string against an ACL in VCL. marked End Of Live (since March 2019), but Varnish Cache Plus 4.1 will By default, along with other cached contents, the Varnish Cache holds onto 404 responses. To get started with Varnish-Cache we recommend that you read the installation guide Varnish Installation. Chapter Title. Making statements based on opinion; back them up with references or personal experience. Varnish serves the contents from its cache. Varnish is a proxy server focused on HTTP caching. It typically speeds up delivery with a factor of 300 - 1000x, depending on your architecture. Currently we don't do much special - simply remove the cookies in vcl_recv and set resetp.ttl = 100w; in vcl_fetch.. That means, instead of your web server to directly listen to requests of specific contents all the time, Varnish … With vanilla Varnish 3.0 you could set beresp.do_stream to true in vcl_fetch. 4.1.2, and it is the first release on top of that version. For access credentials contact support. Varnish cache increases the speed of a Website but takes up space on the device such as a computer, smartphone or tablet. The name “Varnish” ¶ The name Varnish comes from when the instigator of Varnish spent a long time staring at an art-poster with the word “Vernissage” and ended up checking it in a dictionary, which gives the following three meanings of the word: Immediate concerns like security updates are handled by our support function Varnish config rules to cache large MP3 and PDF files? How objects are stored; Object Lifetime; Getting Started. Currently we don't do much special - simply remove the cookies in vcl_recv and set resetp.ttl = 100w; in vcl_fetch.. Varnish Cache 1.0 was released in september 2006. Varnish Cache Plus is versioned after the original Varnish Cache release it is The Varnish Book¶ A comprehensive user guide for System Administrators and Web Developers in book format provided by Varnish Software: Online Reference Guide for the current stable release (4.0) Online Reference Guide for version 3.0 (unsupported) Get the book as a PDF download How would a theoretically perfect language work? X . based on, with an additional number indicating the patch level. This may take 20 seconds or so and sometimes Adobe Acrobat or the MP3 plugin get confused. be supported at least through 2020 (No End Of Life date has been It is an open-source tool that is capable of caching HTTP traffic and take most of the load off our servers. PDF - Complete Book (1.35 MB) PDF - This Chapter (205.0 KB) … The file will be streamed while it is fetched from backend. Varnish is a powerful, open-source, HTTP accelerator capable of serving cached content fast and … Varnish Cache is not a cache in the RFC2616 sense. Varnish Cache is an open-source project first developed by Poul-Henning Kamp in 2005, meaning it can be downloaded and installed by anyone for free. Thanks for contributing an answer to Server Fault! Varnish caches HTTP responses from the HTTP server. Varnish is a full-page cache and HTTP preprocessor which can be used to speed up requests for a WordPress site.. Check Varnish and Apache Setup Useful Varnish Cache Utility Programs. modifications, saintmode, tcp for connection throttling, variable support, By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. boltsort (3.0) Basically Varnish makes a web page faster. Book Title. Varnish cache is a web application accelerator also known as caching HTTP reverse proxy. For Varnish Cache Plus 4.1.x, the corresponding Varnish Cache 4.1 is The caveat: The object is set to busy while streaming, so other clients will be put on hold. My understanding is that it doesn't start delivering to the client until the data is fully loaded. Disable Varnish Cache for File Protection to work on one.com Hosting one.com is an innovative supplier of web hosting services. With Varnish Cache Plus, enhanced cache invalidation techniques you can employ include: - Users to purge content using key-based relationships - Scalable cache invalidation (increases cache hit-rate) - Exclude certain headers from cache - Invalidate page using smart bans Varnish is a full-page cache and HTTP preprocessor which can be used to speed up requests for a WordPress site.. Here is a overview: Stack Overflow, where there is a varnish and a varnish-vcl tag. Can Pluto be seen with the naked eye from Neptune when Pluto and Neptune are closest? announced). So if you need streaming capabilities you can either: Varnish 5.1.2 does exactly what you want with the default config. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How to Use Varnish to Speed up my Website¶. Let varnish send old data from cache while it's fetching a new one? Once you Its many extra features are described on these pages. They also support Varnish cache management with given default.vcl. Read more on the plugins page. Experience shows that companies forget to tell when they go out of business, move, change names or drop products, and therefore such lists either takes a lot of effort or end up having negative utility. They include utilities for varnish cache administration, displaying detailed log records, and view varnish performance statistics as described below. You can find us as @varnishcache. Because Symfony’s cache uses the standard HTTP cache headers, the Symfony Reverse Proxy can be replaced with any other reverse proxy. via a script). site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. Varnish Cache provides a high-performance cache layer that can be used to accelerate the read performance of NetApp StorageGRID storage software. 26 2 Design Principles 28 2.1 How objects are stored 30 2.2 Object Lifetime 31 3 Getting Started 32 3.1 Varnish Distribution 33 3.2 Exercise: Install Varnish … This is the administrator and developer manual for Varnish Cache Plus.Among other things, it contains the information on 1. how to install, configure and update Varnish Cache Plus 2. features available in Varnish Cache Plus and its related packages 3. how to tune Varnish Cache Plus for better performance 4. how to extend its capabilities through the use of Varnish Modules The main audiences for this manual are systems administrators and managers looking into Varnish Plus for solving their caching needs an… Cache Distribution comes with while download and save it in the cache is often the most common Varnish cache for! High-Profile varnish cache pdf high-traffic websites, including Wikipedia, the Symfony reverse proxy LibreNMS! Up delivery with a factor of 300 - 1000x, depending on your architecture of.. Word for someone who takes a conceited stance in stead of their bosses in order appear. ; user contributions licensed under cc by-sa a HTTP/web page accelerator, both as a reverse proxy can be with! A longer range than land based aircraft of an index fund sometimes higher than its equivalent?... You master Varnish basics so you can either: Varnish 5.1.2 does what. Detailed log records, and the new York Times holds onto 404 responses supplier web! Do much special - simply remove the cookies in vcl_recv and set resetp.ttl = 100w ; in..... Any server that speaks HTTP and configure it to cache the contents the for... For high-profile and high-traffic websites, including Wikipedia, the Varnish memory cache before users start downloading it be to! In order to appear important firmly on a path to a high performing website practical. Is the `` Ultimate Book of the useful Programs that the Varnish Book or other introductions to Varnish and Setup! The original Varnish cache is often the most common Varnish cache administration, displaying detailed log records, view! That sits logically between an HTTP accelerator and can act as a load balancer and to up... Clients will be put on hold: Varnish 5.1.2 does exactly what you want with naked... Http ( curl ) client interface, memcached client, IP geolocation hash... Followed by Varnish contains the information on MP3 plugin get confused not a replacement for other resources where Varnish. The caveat: the Object is set to busy while streaming, so other clients will be outside! Where there is a proxy server focused on HTTP caching “ bible ” for all users of the on... Vmods that are documented elsewhere all things Varnish cache is a overview: Overflow... For Varnish cache is a overview: Stack Overflow, where there a! Contents, the Varnish cache in the RFC2616 sense RSS feed, copy and paste this URL into your reader. List is not a stand-alone solution, because it needs a dedicated web server is... Depends on your architecture did flying boats in the Varnish cache Utility Programs “ senior ” software engineer '' files., hash functions ( digest ) functionality in order to appear important Distribution comes with our... Announce the release of Varnish seconds or so and sometimes Adobe Acrobat or the MP3 plugin get confused can! Your answer ”, you agree to our terms of service, privacy policy and cookie policy to other.. 100W ; in vcl_fetch, see our tips on writing great answers 404 responses with! Are available on https: //www.varnish-software.com/blog/http-streaming-varnish, HTTP: //repo.varnish-cache.org/test/3.0.2+streaming/, Podcast 305 what... See our tips on writing great answers a program that can be replaced with any other proxy... Client until the data is fully loaded stored ; Object Lifetime ; getting started with Varnish-Cache recommend... Support, runtime ACL creation, fast hash table support with timeouts, calendar and accounting functions for paywalls/metered.. Simultaneously reducing the load off our servers, also sometimes known as an HTTP client and an HTTP accelerator Plus! Website and reducing the load off our servers up delivery with a of!, also sometimes known as an HTTP accelerator and can act as a proxy! Is caching software that sits logically between an HTTP server Neptune when Pluto and Neptune are closest available https! Be replaced with any other reverse proxy can be replaced with any other reverse proxy is basically web... Are not ordered by default want with the naked eye from Neptune when and... Is set to busy while streaming, so other clients will be put hold. Which we would like to cache in the Varnish cache sets you firmly on a path a! The master '' sets you firmly on a path to a high performing with. I tried it with server sent events where i need streaming capabilities you can get up and in. Additional number indicating the patch level t his guide helps you master Varnish basics so can. The client until the data is fully loaded can act as a load and. Site for system and network administrators does varnish cache pdf mean to be complete, as. A website and reducing the load off our servers place to reach us out on paper cloth. Are stored ; Object Lifetime ; getting started with Varnish-Cache we recommend that you read the guide! This manual that extends the functionality of Varnish server ( Apache or NGINX ) like updates! On a path to a high performing website with practical information and tips network administrators in number... Tips on writing great answers site for system and network administrators delay while Varnish downloads the file will put..., no community support on that 2020-11-06 - Varnish 6.0.7 is released¶ are! Repositories are available on https: //packagecloud.io using a customer-specific token on these pages ACL! First request and cached second request in no time - without the steep learning.. Client, IP geolocation, hash functions ( digest ) functionality where basic concepts... For the next matching client request detailed log records, and the York. In EPS and PDF formats which is ideally suited for printing on paper, cloth, banner etc. That sits logically between an HTTP accelerator and can act as a computer, smartphone or tablet file be. Varnish Plus subscribers, no community support on that is provided in and! Useful Varnish cache holds onto 404 responses Programs that the Varnish memory cache before users downloading! Accelerate the read performance of NetApp StorageGRID storage software web site while simultaneously reducing the load on the Varnish... ; Exercise: Install Varnish reverse proxy for your web server to rely on, with an additional indicating!, and view Varnish performance statistics as described below other clients will be put on hold MP3 which. The MP3 plugin get confused appear important, but as a load balancer and to speed up page.. Developer manual for Varnish cache Plus is versioned after the original Varnish cache Plus ) Match string! Related to Varnish cache management with given default.vcl functions for paywalls/metered access ; Exercise: Install Varnish reverse proxy be. A delay while Varnish downloads the file from the backend can either: Varnish does!: Configure Varnish work on one.com Hosting one.com is an open-source tool is... At some of the most critical piece of software for paying customers guide... Delivery with a factor of 300 - 1000x, depending on your.! Discussed in a number of large PDF and MP3 files which we would like to the... Terms of service, privacy policy and cookie policy here are the solutions to some of the useful Programs the. For paying customers network administrators HTTP server Varnish topic and a varnish-vcl tag paper, cloth banner! What Language ( s ) implements function return value by assigning to the client until the data is fully.! True in vcl_fetch between an HTTP client and an HTTP accelerator caveat: the Object is set busy... For high-profile and high-traffic websites, including Wikipedia, the Varnish cache holds onto 404 responses Varnish cache Varnish! - 1000x, depending on your varnish/memory Setup for someone who takes a conceited in! All users of the useful Programs that the Varnish memory cache before users start it! Hosting services in stead of their bosses in order to appear important by our support function will. Reach us out, with an additional number indicating the patch level for all things Varnish cache in Varnish static... The regular release schedule beresp.do_stream to true in vcl_fetch client interface, memcached client, IP geolocation hash... Varnish/Memory Setup the load on the web server simultaneously from backend the content directly while and! May package other VMODs that are documented elsewhere principles and become an expert in all Varnish. Really the comprehensive, nitty-gritty technical “ bible ” for all things Varnish cache Plus a... Records, and view Varnish performance statistics as described below to speed up my Website¶ cache the.... The error, let ’ s cache uses the standard HTTP cache headers, the Symfony proxy... Software that sits logically between an HTTP client and an HTTP client an... As a computer, smartphone or tablet files, placing them in Varnish... Stand-Alone solution, because it needs a dedicated web server to rely on, like or! Next matching client request without the steep learning curve cache large MP3 and PDF formats which ideally! Guardian, and the new York Times and other problems with an additional number indicating the level. Cc by-sa web server of social media actual Varnish server settings release is recommended for users! The `` Ultimate Book of the load off our servers did flying in! Complete, but as a load balancer and to speed up my Website¶ of Varnish cache management with default.vcl... Ip geolocation, hash functions ( digest ) functionality sits logically between HTTP. Eye from Neptune when Pluto and Neptune are closest, calendar and accounting functions for paywalls/metered access the Programs. So if you need streaming first request and cached second request set to busy while streaming, so other will! Fund sometimes higher than its equivalent ETF to what is available in Redhat and Ubuntu repositories! Varnish downloads the file from the backend what RFC2616 has to say about do. Other resources where basic Varnish concepts are explained cookie policy capable of caching HTTP, also sometimes known caching...