{"id":572,"date":"2011-12-17T13:41:49","date_gmt":"2011-12-17T21:41:49","guid":{"rendered":"http:\/\/virendrachandak.wordpress.com\/?p=572"},"modified":"2014-10-22T23:27:18","modified_gmt":"2014-10-23T06:27:18","slug":"migrating-servers-using-dns-ttl-for-minimum-downtime","status":"publish","type":"post","link":"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/","title":{"rendered":"Migrating servers using DNS TTL for minimum downtime"},"content":{"rendered":"<p>You have your site running on an old hardware and want to migrate it to a new upgraded hardware which would result in change of the ipaddress of your site and in turn imply downtime for your site. You want to minimize the downtime due to the change in ipaddress. This can be easily achieved using the Time-to-live (TTL) values of the Domain Naming Service (DNS) entries of your website.<\/p>\n<p>The users usually use your site name and not the ipaddress to visit to your site. DNS is used to resolve the site name to the correct ipaddress. The DNS entry is stored at various levels (browser, OS, proxy server, DNS servers, etc) and is cached for a specific period called as Time-to-live (TTL). Once the TTL expires, the DNS record will be fetched again from the DNS Server. Usually the TTL for a DNS entry is specified as 3600 sec (i.e. 1 hr). The TTL values can be even lower (0, i.e. no caching) or higher (up to 68 years).<\/p>\n<p><!--more--><\/p>\n<p>The TTL values of DNS entry are changed from the Nameservers of your site. They are defined in the DNS Zone files on your nameservers. The variable for TTL is <strong>$TTL<\/strong> and the value for TTL is specified in seconds. For example, if you want to set your TTL to 5 minutes you will use the following line in your Zone file:<\/p>\n<pre class=\"brush: plain; gutter: false; title: ; notranslate\" title=\"\">\r\n$TTL 300\r\n<\/pre>\n<p>Here are steps involved around updating the DNS entry. (These steps are to minimize the effect of DNS entry update and not to update the DNS entry)<\/p>\n<ul>\n<li>Lower the TTL of the record that you want to change to a small value like 5 mins, 1 min, 30 seconds or even less.<\/li>\n<li>Wait the old TTL value for the servers to update to the new TTL values. That means, if the previous TTL value was 1 hour, you should wait for 1 hour after changing the TTL values for all the servers to update to the new TTL value.<\/li>\n<li>Now change the DNS entry.<\/li>\n<li>After changing the DNS entry, wait for the new TTL value for the DNS entry to be updated. After this, the DNS value is updated on all servers which follow the RFC.<\/li>\n<li>Test your changes, and if everything is fine you should increase your TTL values again to a suitable value for your server like 3600 sec (1 hour). If something goes wrong, or you want to change the DNS entry again, then follow the above steps again to update the DNS record.<\/li>\n<\/ul>\n<p>In this entire process the values of your DNS entry are inconsistent only for the new TTL values that you had lowered it to. Also, you can keep the TTL values low all the time, however, this will increase the load on your DNS servers and hence, it is not a good practice. Keeping the values always high can reduce the load on your DNS servers. However, you don&#8217;t want to do that because when you want to change the entry you will have to wait for at least that amount of time before the changes are reflected everywhere, causing inconsistencies in the entries for longer periods of time. Usually the TTL for DNS entries is kept between 1 hour and 1 day.<\/p>\n<p>Also, a few things to note:<\/p>\n<ul>\n<li>Not all servers on the internet respect the TTL values of your DNS entry. Some servers may still ignore the lower TTL value of your DNS entry and cache for longer periods like 1 hour.<\/li>\n<li>Many browsers and Operating Systems also cache the DNS entry, and may or may not respect the TTL value set by you.<\/li>\n<li>The DNS change would not have any effect on the users who access the site using ipaddress. The DNS entry change would affect only the users who use your domain name to access the site. If the users are using your old ipaddress they will still be using your old servers, unless you have some mechanism to redirect them to your new servers.<\/li>\n<\/ul>\n<div style=\"padding-top:30px;\">\n<p><strong>Related Articles<\/strong>:<\/p>\n<ul>\n<li><a href=\"http:\/\/www.dnswatch.info\/articles\/dns-update\" target=\"_blank\" rel=\"external nofollow\">Updating a DNS record<\/a><\/li>\n<li><a href=\"http:\/\/webmonkeyuk.wordpress.com\/2010\/10\/12\/using-dns-ttl-to-control-migrations\/\" target=\"_blank\" rel=\"external nofollow\">Using DNS TTL to control migrations<\/a><\/li>\n<li><a href=\"http:\/\/www.netwidget.net\/books\/apress\/dns\/info\/ttl.html\" target=\"_blank\" rel=\"external nofollow\">Some thoughts on TTL Values<\/a><\/li>\n<li><a href=\"http:\/\/www.tenereillo.com\/BrowserDNSCache.htm\" target=\"_blank\" rel=\"external nofollow\">Overview of DNS Caching In Browsers<\/a><\/li>\n<li><a href=\"http:\/\/kb.mediatemple.net\/questions\/908\/Understanding+TTL+%28time-to-live%29\" target=\"_blank\" rel=\"external nofollow\">Understanding TTL (time-to-live)<\/a><\/li>\n<li><a href=\"http:\/\/www.querycat.com\/question\/8f19b5dc1a7b098ee7d09cf9996803f7\" target=\"_blank\" rel=\"external nofollow\">TTL FAQ<\/a><\/li>\n<li><a href=\"http:\/\/ds9a.nl\/rfc\/dns-anti-spoofing.html\" target=\"_blank\" rel=\"external nofollow\">Measures to prevent DNS spoofing<\/a><\/li>\n<li><a href=\"http:\/\/tools.ietf.org\/html\/rfc1912\" target=\"_blank\" rel=\"external nofollow\">Common DNS Operational and Configuration Errors<\/a><\/li>\n<li><a href=\"http:\/\/en.wikipedia.org\/wiki\/Domain_name_system\" target=\"_blank\" rel=\"external nofollow\">Domain Name System<\/a><\/li>\n<li><a href=\"http:\/\/en.wikipedia.org\/wiki\/Time_to_live#DNS_records\" target=\"_blank\" rel=\"external nofollow\">DNS TTL<\/a><\/li>\n<\/ul>\n<\/div>\n<div style=\"padding-top:30px;\"><span style=\"text-decoration:underline;\"><strong>Note<\/strong><\/span>: I do not take responsibility for proper functioning of the above mentioned steps under all circumstances. I am not responsible for any damages to your computer, website, blog, application or any thing else. I am not affiliated with or do not endorse any of the above mentioned sites.<\/div>\n<div style=\"padding-top:30px;\"><\/div>\n","protected":false},"excerpt":{"rendered":"<p>You have your site running on an old hardware and want to migrate it to a new upgraded hardware which would result in change of the ipaddress of your site and in turn imply downtime for your site. You want to minimize the downtime due to the change in ipaddress. This can be easily achieved [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[5,6,8],"tags":[30,31,42,49,66,67],"class_list":["post-572","post","type-post","status-publish","format-standard","hentry","category-optimization-tips","category-server-configuration","category-web-development","tag-dns","tag-domain-name-system","tag-ip-address","tag-name-server","tag-time-to-live","tag-ttl"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.0 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Migrating servers using DNS TTL for minimum downtime - Virendra&#039;s TechTalk<\/title>\n<meta name=\"description\" content=\"You have your site running on an old hardware and want to migrate it to a new upgraded hardware which would result in change of the ipaddress of your site\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Migrating servers using DNS TTL for minimum downtime - Virendra&#039;s TechTalk\" \/>\n<meta property=\"og:description\" content=\"You have your site running on an old hardware and want to migrate it to a new upgraded hardware which would result in change of the ipaddress of your site\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/\" \/>\n<meta property=\"og:site_name\" content=\"Virendra&#039;s TechTalk\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/virendrachandak\" \/>\n<meta property=\"article:author\" content=\"https:\/\/www.facebook.com\/virendrachandak\" \/>\n<meta property=\"article:published_time\" content=\"2011-12-17T21:41:49+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2014-10-23T06:27:18+00:00\" \/>\n<meta name=\"author\" content=\"Virendra Chandak\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@virendrachandak\" \/>\n<meta name=\"twitter:site\" content=\"@virendrachandak\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Virendra Chandak\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"4 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/migrating-servers-using-dns-ttl-for-minimum-downtime\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/migrating-servers-using-dns-ttl-for-minimum-downtime\\\/\"},\"author\":{\"name\":\"Virendra Chandak\",\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/#\\\/schema\\\/person\\\/63f7ffa1ea125e32af9618d188349e17\"},\"headline\":\"Migrating servers using DNS TTL for minimum downtime\",\"datePublished\":\"2011-12-17T21:41:49+00:00\",\"dateModified\":\"2014-10-23T06:27:18+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/migrating-servers-using-dns-ttl-for-minimum-downtime\\\/\"},\"wordCount\":763,\"commentCount\":1,\"publisher\":{\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/#\\\/schema\\\/person\\\/63f7ffa1ea125e32af9618d188349e17\"},\"keywords\":[\"DNS\",\"Domain Name System\",\"IP address\",\"Name server\",\"Time to live\",\"TTL\"],\"articleSection\":[\"Optimization Tips\",\"Server Configuration\",\"Web Development\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/migrating-servers-using-dns-ttl-for-minimum-downtime\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/migrating-servers-using-dns-ttl-for-minimum-downtime\\\/\",\"url\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/migrating-servers-using-dns-ttl-for-minimum-downtime\\\/\",\"name\":\"Migrating servers using DNS TTL for minimum downtime - Virendra&#039;s TechTalk\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/#website\"},\"datePublished\":\"2011-12-17T21:41:49+00:00\",\"dateModified\":\"2014-10-23T06:27:18+00:00\",\"description\":\"You have your site running on an old hardware and want to migrate it to a new upgraded hardware which would result in change of the ipaddress of your site\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/migrating-servers-using-dns-ttl-for-minimum-downtime\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/migrating-servers-using-dns-ttl-for-minimum-downtime\\\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/migrating-servers-using-dns-ttl-for-minimum-downtime\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"TechTalk\",\"item\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Optimization Tips\",\"item\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/category\\\/optimization-tips\\\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Migrating servers using DNS TTL for minimum downtime\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/#website\",\"url\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/\",\"name\":\"Virendra's TechTalk\",\"description\":\"\",\"publisher\":{\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/#\\\/schema\\\/person\\\/63f7ffa1ea125e32af9618d188349e17\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":[\"Person\",\"Organization\"],\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/#\\\/schema\\\/person\\\/63f7ffa1ea125e32af9618d188349e17\",\"name\":\"Virendra Chandak\",\"logo\":{\"@id\":\"https:\\\/\\\/www.virendrachandak.com\\\/techtalk\\\/#\\\/schema\\\/person\\\/image\\\/\"},\"sameAs\":[\"https:\\\/\\\/www.virendrachandak.com\",\"https:\\\/\\\/www.facebook.com\\\/virendrachandak\",\"https:\\\/\\\/www.linkedin.com\\\/in\\\/virendrachandak\\\/\",\"https:\\\/\\\/x.com\\\/virendrachandak\"]}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Migrating servers using DNS TTL for minimum downtime - Virendra&#039;s TechTalk","description":"You have your site running on an old hardware and want to migrate it to a new upgraded hardware which would result in change of the ipaddress of your site","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/","og_locale":"en_US","og_type":"article","og_title":"Migrating servers using DNS TTL for minimum downtime - Virendra&#039;s TechTalk","og_description":"You have your site running on an old hardware and want to migrate it to a new upgraded hardware which would result in change of the ipaddress of your site","og_url":"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/","og_site_name":"Virendra&#039;s TechTalk","article_publisher":"https:\/\/www.facebook.com\/virendrachandak","article_author":"https:\/\/www.facebook.com\/virendrachandak","article_published_time":"2011-12-17T21:41:49+00:00","article_modified_time":"2014-10-23T06:27:18+00:00","author":"Virendra Chandak","twitter_card":"summary_large_image","twitter_creator":"@virendrachandak","twitter_site":"@virendrachandak","twitter_misc":{"Written by":"Virendra Chandak","Est. reading time":"4 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/#article","isPartOf":{"@id":"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/"},"author":{"name":"Virendra Chandak","@id":"https:\/\/www.virendrachandak.com\/techtalk\/#\/schema\/person\/63f7ffa1ea125e32af9618d188349e17"},"headline":"Migrating servers using DNS TTL for minimum downtime","datePublished":"2011-12-17T21:41:49+00:00","dateModified":"2014-10-23T06:27:18+00:00","mainEntityOfPage":{"@id":"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/"},"wordCount":763,"commentCount":1,"publisher":{"@id":"https:\/\/www.virendrachandak.com\/techtalk\/#\/schema\/person\/63f7ffa1ea125e32af9618d188349e17"},"keywords":["DNS","Domain Name System","IP address","Name server","Time to live","TTL"],"articleSection":["Optimization Tips","Server Configuration","Web Development"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/","url":"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/","name":"Migrating servers using DNS TTL for minimum downtime - Virendra&#039;s TechTalk","isPartOf":{"@id":"https:\/\/www.virendrachandak.com\/techtalk\/#website"},"datePublished":"2011-12-17T21:41:49+00:00","dateModified":"2014-10-23T06:27:18+00:00","description":"You have your site running on an old hardware and want to migrate it to a new upgraded hardware which would result in change of the ipaddress of your site","breadcrumb":{"@id":"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.virendrachandak.com\/techtalk\/migrating-servers-using-dns-ttl-for-minimum-downtime\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"TechTalk","item":"https:\/\/www.virendrachandak.com\/techtalk\/"},{"@type":"ListItem","position":2,"name":"Optimization Tips","item":"https:\/\/www.virendrachandak.com\/techtalk\/category\/optimization-tips\/"},{"@type":"ListItem","position":3,"name":"Migrating servers using DNS TTL for minimum downtime"}]},{"@type":"WebSite","@id":"https:\/\/www.virendrachandak.com\/techtalk\/#website","url":"https:\/\/www.virendrachandak.com\/techtalk\/","name":"Virendra's TechTalk","description":"","publisher":{"@id":"https:\/\/www.virendrachandak.com\/techtalk\/#\/schema\/person\/63f7ffa1ea125e32af9618d188349e17"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.virendrachandak.com\/techtalk\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":["Person","Organization"],"@id":"https:\/\/www.virendrachandak.com\/techtalk\/#\/schema\/person\/63f7ffa1ea125e32af9618d188349e17","name":"Virendra Chandak","logo":{"@id":"https:\/\/www.virendrachandak.com\/techtalk\/#\/schema\/person\/image\/"},"sameAs":["https:\/\/www.virendrachandak.com","https:\/\/www.facebook.com\/virendrachandak","https:\/\/www.linkedin.com\/in\/virendrachandak\/","https:\/\/x.com\/virendrachandak"]}]}},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p2vTtQ-9e","jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":450,"url":"https:\/\/www.virendrachandak.com\/techtalk\/getting-real-client-ip-address-in-php-2\/","url_meta":{"origin":572,"position":0},"title":"Getting real client IP address in PHP","author":"Virendra Chandak","date":"October 23, 2011","format":false,"excerpt":"Many times we need the visitor's ipaddress for validation, security, spam prevention, etc. Getting the Visitor's ipaddress is very easy in PHP. The simplest way to get the visitor's\/client's ipaddress is using the $_SERVER['REMOTE_ADDR'] or $_SERVER['REMOTE_HOST'] variables. The variable in the $_SERVER array are created by the web server (like\u2026","rel":"","context":"In &quot;Functionality&quot;","block_context":{"text":"Functionality","link":"https:\/\/www.virendrachandak.com\/techtalk\/category\/functionality\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":255,"url":"https:\/\/www.virendrachandak.com\/techtalk\/more-htaccess-tips\/","url_meta":{"origin":572,"position":1},"title":"more .htaccess tips","author":"Virendra Chandak","date":"October 16, 2011","format":false,"excerpt":"In my previous post .htaccess tips I had started with what is .htaccess file and some things that can be done using it. In this post I'll cover more about .htaccess files. Topics Covered: Directory index file Redirection Preferred domain (www or non-www) Redirect old site to new site Redirect\u2026","rel":"","context":"In &quot;Server Configuration&quot;","block_context":{"text":"Server Configuration","link":"https:\/\/www.virendrachandak.com\/techtalk\/category\/server-configuration\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":802,"url":"https:\/\/www.virendrachandak.com\/techtalk\/voting-functionality-in-a-website\/","url_meta":{"origin":572,"position":2},"title":"Voting Functionality in a website","author":"Virendra Chandak","date":"April 10, 2011","format":false,"excerpt":"In this post I will give the step by step explanation of how we can add Voting Functionality to a website. At the end of this article we will have a working sample voting application. The source code for the sample voting application can be downloaded from here. We will\u2026","rel":"","context":"In &quot;Functionality&quot;","block_context":{"text":"Functionality","link":"https:\/\/www.virendrachandak.com\/techtalk\/category\/functionality\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.virendrachandak.com\/techtalk\/wp-content\/uploads\/2011\/10\/initial.png?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":803,"url":"https:\/\/www.virendrachandak.com\/techtalk\/parts-of-url\/","url_meta":{"origin":572,"position":3},"title":"Parts of URL","author":"Virendra Chandak","date":"May 26, 2012","format":false,"excerpt":"We see so many URLs everyday, but do we know what are the parts of an URL, what does each part means? In this post I will discuss the various parts of the URL. An URL may consists of as many as 6 parts. The different parts of the URL\u2026","rel":"","context":"In &quot;Glossary\/Definitions&quot;","block_context":{"text":"Glossary\/Definitions","link":"https:\/\/www.virendrachandak.com\/techtalk\/category\/glossarydefinitions\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":205,"url":"https:\/\/www.virendrachandak.com\/techtalk\/tools-for-web-development\/","url_meta":{"origin":572,"position":4},"title":"Tools for Web Development","author":"Virendra Chandak","date":"August 15, 2011","format":false,"excerpt":"With so many tools available for Web Development its hard to find the right tools for the job. In this post I will mention some of the tools that I personally use for Web Development. Also, I will give links to some websites which can be really helpful for certain\u2026","rel":"","context":"In &quot;Tools&quot;","block_context":{"text":"Tools","link":"https:\/\/www.virendrachandak.com\/techtalk\/category\/tools\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1090,"url":"https:\/\/www.virendrachandak.com\/techtalk\/how-to-hide-apache-information-with-servertokens-and-serversignature-directives\/","url_meta":{"origin":572,"position":5},"title":"How to hide apache information with ServerTokens and ServerSignature directives","author":"Virendra Chandak","date":"February 19, 2013","format":false,"excerpt":"In default Apache configuration, the server sends HTTP Header with the information of Apache version, modules, Operating System, etc of the Server. The HTTP response header \u201cServer\u201d displays all these details of the server. This information can be used by hackers to try to exploit any vulnerabilities in the Apache,\u2026","rel":"","context":"In &quot;Server Configuration&quot;","block_context":{"text":"Server Configuration","link":"https:\/\/www.virendrachandak.com\/techtalk\/category\/server-configuration\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.virendrachandak.com\/techtalk\/wp-json\/wp\/v2\/posts\/572","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.virendrachandak.com\/techtalk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.virendrachandak.com\/techtalk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.virendrachandak.com\/techtalk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.virendrachandak.com\/techtalk\/wp-json\/wp\/v2\/comments?post=572"}],"version-history":[{"count":0,"href":"https:\/\/www.virendrachandak.com\/techtalk\/wp-json\/wp\/v2\/posts\/572\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.virendrachandak.com\/techtalk\/wp-json\/wp\/v2\/media?parent=572"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.virendrachandak.com\/techtalk\/wp-json\/wp\/v2\/categories?post=572"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.virendrachandak.com\/techtalk\/wp-json\/wp\/v2\/tags?post=572"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}