{"id":1479,"date":"2021-05-10T13:34:05","date_gmt":"2021-05-10T10:34:05","guid":{"rendered":"https:\/\/www.scalahosting.com\/kb\/?p=1479"},"modified":"2024-02-06T11:32:42","modified_gmt":"2024-02-06T09:32:42","slug":"how-to-configure-reverse-dns","status":"publish","type":"post","link":"https:\/\/www.scalahosting.com\/kb\/how-to-configure-reverse-dns\/","title":{"rendered":"How to configure reverse DNS"},"content":{"rendered":"<p><span style=\"font-weight: 400;\">When a visitor types a domain name, the browser <\/span><b>queries DNS servers<\/b><span style=\"font-weight: 400;\"> for its IP address. The process, also known as<\/span><b> forward DNS lookup<\/b><span style=\"font-weight: 400;\">, resolves the domain names to IP addresses, enabling users to connect to websites without memorizing IP addresses.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">But you could also configure your server to <\/span><b>reverse the DNS lookup process. <\/b><span style=\"font-weight: 400;\">This article guides you on everything you need to know on reverse DNS and how to configure it.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Let\u2019s get started.<\/span><\/p>\n<h2><b>What\u2019s Reverse DNS?<\/b><\/h2>\n<p><i><span style=\"font-weight: 400;\">Reverse DNS queries DNS for a hostname based on an IP address.<\/span><\/i><\/p>\n<p><span style=\"font-weight: 400;\">It\u2019s a method of<\/span><b> resolving IP addresses into domain names<\/b><span style=\"font-weight: 400;\"> rather than the typical resolution from domain name to IP addresses. Reverse DNS is also known as rDNS or reverse DNS resolution.<\/span><\/p>\n<p><b>It\u2019s the opposite of forward DNS lookup, and here\u2019s how they differ:<\/b><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Forward DNS takes the <\/span><a href=\"https:\/\/www.scalahosting.com\/kb\/hosting\/dns\/\"><b>domain name<\/b><\/a><span style=\"font-weight: 400;\"> as the input and returns the associated IP address as output, while rDNS uses the IP address as input.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">The former uses a <\/span><b>domain\u2019s A<\/b> <i><span style=\"font-weight: 400;\">(or Alias) <\/span><\/i><span style=\"font-weight: 400;\">record to determine its IP address, while reverse DNS uses <\/span><b>PTR records<\/b> <i><span style=\"font-weight: 400;\">(or Pointer Records)<\/span><\/i><span style=\"font-weight: 400;\"> to determine an IP address\u2019s domain name.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Forward DNS is often <\/span><b>suitable for accessing a website<\/b><span style=\"font-weight: 400;\"> over the internet, while reverse DNS works best for network troubleshooting, for instance, finding the domain name of the IP address that has a problem.\u00a0<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">This<\/span><b> Leadfeeder\u2019s graphics<\/b><span style=\"font-weight: 400;\"> summarizes perfectly how the two differ.<\/span><\/p>\n<p><img decoding=\"async\" class=\"aligncenter size-full wp-image-1480\" src=\"https:\/\/www.scalahosting.com\/kb\/wp-content\/uploads\/2021\/05\/2021-05-10_13h31_59.png\" alt=\"How to configure reverse DNS, What\u2019s Reverse DNS?\" width=\"488\" height=\"259\" srcset=\"https:\/\/www.scalahosting.com\/kb\/wp-content\/uploads\/2021\/05\/2021-05-10_13h31_59.png 488w, https:\/\/www.scalahosting.com\/kb\/wp-content\/uploads\/2021\/05\/2021-05-10_13h31_59-300x159.png 300w\" sizes=\"(max-width: 361px) 660px, (max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 910px, 1140px\" \/><\/p>\n<p><span style=\"font-weight: 400;\">Forward DNS asks for the IP address of a domain, while rDNS interest is in knowing who owns an IP address.<\/span><\/p>\n<h2><b>Understanding Reverse DNS\u2019 Pointer Records<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">The <\/span><a href=\"https:\/\/www.scalahosting.com\/kb\/dns-records-explained\/\"><b>DNS pointer<\/b><\/a><span style=\"font-weight: 400;\"> records, or PTR records, in short, drive rDNS operations. The records are helpful in the reverse DNS lookup, and it\u2019s exactly opposite to the A records, which<\/span><b> provide the IP address <\/b><span style=\"font-weight: 400;\">associated with a domain name.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">The PTR records store domain information under reserved IP addresses and append the suffix, <\/span><b>.in-addr.arpa<\/b><span style=\"font-weight: 400;\"> at the end. For instance, it stores <\/span><b>Google\u2019s domain information<\/b> <i><span style=\"font-weight: 400;\">(Google\u2019s IP address is 216.58.211.142)<\/span><\/i><span style=\"font-weight: 400;\"> under<\/span><b> 142.211.58.216.in-addr.arpa<\/b><span style=\"font-weight: 400;\">\u2014you could notice the reversed IP address.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">But in <\/span><b>IPv6,<\/b><span style=\"font-weight: 400;\"> the latest version of the internet protocol, the PTR records store the IP addresses <\/span><span style=\"font-weight: 400;\">within the <\/span><b>&#8216;.ip6.arpa&#8217; <\/b><span style=\"font-weight: 400;\">domain rather than &#8216;<\/span><b>.in-addr.arpa.&#8217;<\/b><b>\u00a0<\/b><\/p>\n<h2><b>The Importance of Reverse DNS<\/b><\/h2>\n<p><b>Let\u2019s look at some of what makes using reverse DNS essential :<\/b><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It helps users to <\/span><b>track the location of website visitors.<\/b><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Reverse DNS lookup is essential in the email system. It helps identify the origin of email messages.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It\u2019s helpful in <\/span><b>network troubleshooting.<\/b><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">rDNS helps businesses uncover the companies<\/span><b> visiting their websites<\/b><span style=\"font-weight: 400;\"> by looking up the records associated with their IP addresses. B2B businesses can look up the IP addresses of website visitors using a<\/span><b> reverse DNS tool <\/b><span style=\"font-weight: 400;\">to identify potential clients.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It helps validate email servers to reduce spam.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Logging software uses reverse DNS to provide users with <\/span><b>easy-to-read domains<\/b><span style=\"font-weight: 400;\"> in their log data instead of the difficult-to-memorize numerical IP addresses.<\/span><\/li>\n<\/ul>\n<h2><b>Why You Should Be Careful With Reverse DNS\u00a0<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">Reverse DNS doesn\u2019t offer you a bed of roses on a platter of gold.\u00a0<\/span><\/p>\n<p><b>Here are just a few reasons you should be careful about configuring it :<\/b><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Enabling reverse DNS <\/span><b>increases network traffic<\/b><span style=\"font-weight: 400;\"> which could decrease server performance.<\/span><\/li>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">Reverse DNS is optional. It\u2019s not critical to the <\/span><b>normal functioning of the internet.<\/b><\/li>\n<\/ul>\n<h2><b>Testing a Reverse DNS<\/b><\/h2>\n<p><span style=\"font-weight: 400;\">You can look up an IP address with a <\/span><b>quick and simple command <\/b><span style=\"font-weight: 400;\">to determine if there&#8217;s a PTR record associated with it. You can get started by logging in to your account using <\/span><a href=\"https:\/\/www.scalahosting.com\/kb\/access-server-ssh\/\"><b>SSH Access.<\/b><\/a><\/p>\n<p><span style=\"font-weight: 400;\">A secure shell is a <\/span><b>network communication protocol<\/b><span style=\"font-weight: 400;\"> that allows computers to communicate securely over an open network, such as the internet. It provides a strong password, public keys authentications, and encrypted data communication between two computers<\/span><b> connecting over an unsecured network.\u00a0<\/b><\/p>\n<p><span style=\"font-weight: 400;\">SSH authenticates a remote user, transfers input from the host to the server, and relays the outputs back to the host. Thankfully, we have an article that guides you on <\/span><a href=\"https:\/\/www.scalahosting.com\/kb\/how-to-enable-ssh-access\/\"><b>enabling SSH<\/b><\/a><b> and connecting to your server <\/b><span style=\"font-weight: 400;\">using the protocol.<\/span><\/p>\n<p><b>Run this command at the command prompt after connecting to your server via SSH Access :<\/b><\/p>\n<ul>\n<li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">dig -x 000.000.000.000<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">Replace <\/span><b><i>000.000.000.000<\/i><\/b> <span style=\"font-weight: 400;\">with the IP address you want to text. If you test the <\/span><b>IP address 75.8.175.166<\/b><span style=\"font-weight: 400;\"> at the command prompt, Dig\u2014<\/span><span style=\"font-weight: 400;\">command-line tool for troubleshooting DNS issues<\/span><span style=\"font-weight: 400;\">.<\/span><\/p>\n<p><b>It responds with an output that looks thus:<\/b><\/p>\n<p><span style=\"font-weight: 400;\">The output shows the <\/span><b>IP address <\/b><b>75.8.175.166<\/b><span style=\"font-weight: 400;\"> belongs to the domain name in the <\/span><b>ANSWER SECTION.<\/b><\/p>\n<p><span style=\"font-weight: 400;\">The \u2018<\/span><i><span style=\"font-weight: 400;\">QUESTION SECTION<\/span><\/i><span style=\"font-weight: 400;\">\u2019 shows the requests, while the \u2018<\/span><i><span style=\"font-weight: 400;\">ANSWER SECTION<\/span><\/i><span style=\"font-weight: 400;\">\u2019 displays the response to the requests.<\/span><\/p>\n<h2><b>Configuring Reverse DNS<\/b><\/h2>\n<p><a href=\"https:\/\/www.scalahosting.com\/\"><b>ScalaHosting\u2019s<\/b><\/a><span style=\"font-weight: 400;\"> Shared and Reseller comes with<\/span><b> rDNS configured <\/b><span style=\"font-weight: 400;\">for the primary IP addresses. But if you are using VPS or a dedicated server, you could contact us to configure the reverse DNS for your account.<\/span><\/p>\n<p><a href=\"https:\/\/www.scalahosting.com\/contact-us.html\"><b>Contact us<\/b><\/a><span style=\"font-weight: 400;\"> and specify the domain you want to set up rDNS for, as well as the account\u2019s IP address, and our team will get it done quickly.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">That\u2019s it.<\/span><\/p>\n<p><i><span style=\"font-weight: 400;\">Simple, right?<\/span><\/i><\/p>\n","protected":false},"excerpt":{"rendered":"<p>When a visitor types a domain name, the browser queries DNS servers for its IP address. The process, also known as forward DNS lookup, resolves the domain names to IP addresses, enabling users to connect to websites without memorizing IP addresses.\u00a0 But you could also configure your server to reverse the DNS lookup process. This [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_robots_primary_cat":"none","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","footnotes":""},"categories":[22],"tags":[],"class_list":["post-1479","post","type-post","status-publish","format-standard","hentry","category-dns"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.scalahosting.com\/kb\/wp-json\/wp\/v2\/posts\/1479","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.scalahosting.com\/kb\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.scalahosting.com\/kb\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.scalahosting.com\/kb\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.scalahosting.com\/kb\/wp-json\/wp\/v2\/comments?post=1479"}],"version-history":[{"count":3,"href":"https:\/\/www.scalahosting.com\/kb\/wp-json\/wp\/v2\/posts\/1479\/revisions"}],"predecessor-version":[{"id":5702,"href":"https:\/\/www.scalahosting.com\/kb\/wp-json\/wp\/v2\/posts\/1479\/revisions\/5702"}],"wp:attachment":[{"href":"https:\/\/www.scalahosting.com\/kb\/wp-json\/wp\/v2\/media?parent=1479"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.scalahosting.com\/kb\/wp-json\/wp\/v2\/categories?post=1479"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.scalahosting.com\/kb\/wp-json\/wp\/v2\/tags?post=1479"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}