{"id":2268,"date":"2025-07-11T09:51:59","date_gmt":"2025-07-11T09:51:59","guid":{"rendered":"https:\/\/hostrago.com\/knowledge-base\/?p=2268"},"modified":"2025-07-11T09:52:02","modified_gmt":"2025-07-11T09:52:02","slug":"reverse-dns-cache-mail-helo-setup","status":"publish","type":"post","link":"https:\/\/hostrago.com\/knowledge-base\/reverse-dns-cache-mail-helo-setup\/","title":{"rendered":"How to Rebuild PTR \/ Reverse DNS Cache and Update Mail HELO for Email Deliverability in WHM\/cPanel?"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Ensuring reliable email deliverability is essential for any web hosting provider or business that sends transactional or marketing emails. One of the most common issues that affect deliverability is improper Reverse DNS Cache, which is directly linked to PTR records and Mail HELO configuration. Without properly set Reverse DNS records, your email might land in the spam folder\u2014or worse\u2014get blocked by mail servers.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In this step-by-step blog, we\u2019ll walk you through the complete process to <strong>rebuild the PTR or Reverse DNS cache<\/strong> and how to <strong>update Mail HELO in WHM\/cPanel<\/strong> to ensure your emails are authenticated and trusted. This guide is especially important for system admins or hosting providers using Hostrago\u2019s VPS or Dedicated Servers.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What is PTR or Reverse DNS?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">PTR (Pointer) records are the <strong>Reverse DNS records<\/strong> that map an <strong>IP address to a hostname<\/strong>. Unlike A records (which point domain names to IPs), PTR records confirm to email servers that the IP sending the message is associated with the correct hostname.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Most modern email servers verify PTR records before accepting emails. If there&#8217;s a mismatch or absence of a proper <strong>Reverse DNS WHM setup<\/strong>, your emails may be rejected or flagged as suspicious.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Why is it important?<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Helps email servers verify your identity<\/li>\n\n\n\n<li>Prevents emails from being marked as spam<\/li>\n\n\n\n<li>Enhances your domain reputation<\/li>\n\n\n\n<li>Necessary for proper <strong>SPF, DKIM, and DMARC<\/strong> implementation<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Steps to Rebuild the Reverse DNS (PTR) Cache in WHM<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Follow the steps below to manually <strong>rebuild the PTR cache<\/strong> via WHM:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Step 1: Login to WHM<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Access <a href=\"https:\/\/www.cpanel.net\/products\/cpanel-whm-features\/\" target=\"_blank\" rel=\"noopener\">WHM <\/a>by navigating to: <code>https:\/\/your-server-ip:2087<\/code><\/li>\n\n\n\n<li>Enter your <strong>root<\/strong> credentials<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Step 2: Navigate to \u201cServer Configuration\u201d<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>From the WHM dashboard, search for <strong>\u201cServer Configuration\u201d<\/strong>.<\/li>\n\n\n\n<li>Click on the <strong>\u201cExim Configuration Manager\u201d<\/strong> under \u201cService Configuration.\u201d<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"227\" src=\"https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Navigate-to-Mail-Server-Configuration-1024x227.webp\" loading=\"lazy\" alt=\"Navigate to \u201cMail Server Configuration\u201d\" class=\"wp-image-2270\" srcset=\"https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Navigate-to-Mail-Server-Configuration-1024x227.webp 1024w, https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Navigate-to-Mail-Server-Configuration-300x67.webp 300w, https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Navigate-to-Mail-Server-Configuration-768x170.webp 768w, https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Navigate-to-Mail-Server-Configuration-1536x341.webp 1536w, https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Navigate-to-Mail-Server-Configuration-2048x454.webp 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Step 3: Rebuild Reverse DNS Cache<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Inside <strong>Exim Configuration Manager<\/strong>, go to the <strong>Advanced Editor<\/strong> tab.<\/li>\n\n\n\n<li>Locate the section: cssCopyEdit<code>@CONFIG@<\/code><\/li>\n\n\n\n<li>Insert the following directive to refresh the RDNS cache: bashCopyEdit<code>host_lookup = *<\/code><\/li>\n\n\n\n<li>Save and <strong>restart Exim<\/strong> to apply the changes.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"354\" src=\"https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Rebuild-Reverse-DNS-Cache-1024x354.webp\" loading=\"lazy\" alt=\"Rebuild Reverse DNS Cache\" class=\"wp-image-2269\" srcset=\"https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Rebuild-Reverse-DNS-Cache-1024x354.webp 1024w, https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Rebuild-Reverse-DNS-Cache-300x104.webp 300w, https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Rebuild-Reverse-DNS-Cache-768x265.webp 768w, https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Rebuild-Reverse-DNS-Cache-1536x531.webp 1536w, https:\/\/hostrago.com\/knowledge-base\/wp-content\/uploads\/2025\/07\/Rebuild-Reverse-DNS-Cache-2048x708.webp 2048w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">This action prompts WHM\/cPanel to refresh its cache with the latest PTR record information for your server&#8217;s IP addresses. Consequently, the Mail HELO will be updated to match the retrieved domain name.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">That&#8217;s all. For email deliverability in WHM\/cPanel, you can refer to this article: Rebuild Reverse DNS Cache and Update Mail HELO.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">You can contact us through ticket or chat if you are experiencing any issues with Rebuild Reverse DNS Cache.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Final Thoughts<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Correctly configuring <strong>Reverse DNS in WHM setup<\/strong> and updating your <strong>Mail HELO identity<\/strong> is essential for improving email deliverability and maintaining your server\u2019s IP reputation. If you\u2019re using <strong>Hostrago\u2019s VPS or Dedicated Hosting<\/strong>, our support team can assist you with PTR updates and proper hostname configuration to ensure smooth and secure email operations.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\ud83d\udce7 Still facing issues? Contact <a href=\"https:\/\/hostrago.com\/contact-us\/\">Hostrago Support<\/a> and we\u2019ll handle your email configuration for you!<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Ensuring reliable email deliverability is essential for any web hosting provider or business that sends transactional or marketing emails. One of the most common issues&#8230;<\/p>\n","protected":false},"author":1,"featured_media":2271,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[551,549,553,552,550],"class_list":["post-2268","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-whm","tag-email-deliverability-whm","tag-mail-helo-whm","tag-ptr-record-update","tag-reverse-dns-whm-setup","tag-whm-reverse-dns"],"menu_order":0,"_links":{"self":[{"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/posts\/2268","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/comments?post=2268"}],"version-history":[{"count":1,"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/posts\/2268\/revisions"}],"predecessor-version":[{"id":2272,"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/posts\/2268\/revisions\/2272"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/media\/2271"}],"wp:attachment":[{"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/media?parent=2268"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/categories?post=2268"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hostrago.com\/knowledge-base\/wp-json\/wp\/v2\/tags?post=2268"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}