{"id":1521,"date":"2015-05-12T21:24:36","date_gmt":"2015-05-13T03:24:36","guid":{"rendered":"http:\/\/www.supportpro.com\/blog\/?p=1521"},"modified":"2026-03-04T03:21:41","modified_gmt":"2026-03-04T09:21:41","slug":"load-balancing-via-round-robin-dns","status":"publish","type":"post","link":"https:\/\/www.supportpro.com\/blog\/load-balancing-via-round-robin-dns\/","title":{"rendered":"Load Balancing via Round Robin DNS"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">When you need to distribute website traffic across multiple servers without investing in a hardware or cloud load balancer, <strong>Round Robin DNS<\/strong> offers a simple and cost-effective solution.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">It is one of the oldest and most commonly used DNS load balancing techniques, especially for websites hosted on multiple servers with identical configurations.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In this guide, we\u2019ll explain how Round Robin DNS works, how to configure it in BIND, and the impact of TTL and DNS caching on load balancing performance.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What Is Round Robin DNS?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Round Robin DNS<\/strong> is a load balancing mechanism in which a DNS server rotates multiple IP addresses for a single domain name. Instead of returning the same IP address every time, the DNS server cycles through a list of IPs.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This helps distribute traffic across multiple servers and improves availability.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For example:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If a domain has three A records:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>example.com. 1301 IN A 192.168.1.10<br>example.com. 1301 IN A 192.168.1.11<br>example.com. 1301 IN A 192.168.1.12<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">The DNS server returns the IPs in cyclic order:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>First request \u2192 192.168.1.10<\/li>\n\n\n\n<li>Second request \u2192 192.168.1.11<\/li>\n\n\n\n<li>Third request \u2192 192.168.1.12<\/li>\n\n\n\n<li>Fourth request \u2192 192.168.1.10 (rotation continues)<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">This rotation is controlled by the <strong>RR-set order<\/strong> in DNS.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How Round Robin DNS Works<\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li>A client requests a domain name.<\/li>\n\n\n\n<li>The DNS server checks for multiple A records.<\/li>\n\n\n\n<li>It returns the IP addresses in cyclic (round-robin) order.<\/li>\n\n\n\n<li>The selected IP is used for that session.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Important:<br>Round Robin DNS distributes traffic <strong>per session<\/strong>, not per HTTP request. Once a client connects to an IP, it continues using that server until the session ends.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How to Configure Round Robin DNS in BIND<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">To enable cyclic ordering in BIND, edit the configuration file:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\/etc\/named.conf<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Add:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>options {<br>    rrset-order {<br>        order cyclic;<br>    };<br>};<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">Available RR-set Orders<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><div class=\"pcrstb-wrap\"><table class=\"has-fixed-layout\"><thead><tr><th>Order Type<\/th><th>Description<\/th><\/tr><\/thead><tbody><tr><td>fixed<\/td><td>Returns records in the same order<\/td><\/tr><tr><td>random<\/td><td>Returns records randomly<\/td><\/tr><tr><td>cyclic<\/td><td>Returns records in round-robin order<\/td><\/tr><\/tbody><\/table><\/div><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">You can also configure it more specifically:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>options {<br>    rrset-order {<br>        class IN type ANY name \"*\" order cyclic;<br>    };<br>};<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">By default, many DNS servers already rotate Resource Records when multiple entries exist for the same domain.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The Role of TTL in Round Robin DNS<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">DNS caching significantly affects the effectiveness of Round Robin DNS.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>If TTL is too high \u2192 Clients reuse cached IPs \u2192 Less load distribution<\/li>\n\n\n\n<li>If TTL is set to 0 \u2192 Every request hits the DNS server \u2192 Higher DNS load<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Recommended TTL<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">For balanced performance:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Set TTL between 10\u201315 minutes<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This allows:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Effective caching<\/li>\n\n\n\n<li>Better traffic distribution<\/li>\n\n\n\n<li>Reduced DNS server load<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Advantages of Round Robin DNS<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Simple to configure<\/li>\n\n\n\n<li>No additional hardware required<\/li>\n\n\n\n<li>Cost-effective<\/li>\n\n\n\n<li>Improves traffic distribution<\/li>\n\n\n\n<li>Supports multiple A and MX records<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Limitations of Round Robin DNS<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>No health checks (unlike advanced load balancers)<\/li>\n\n\n\n<li>Does not detect server failure<\/li>\n\n\n\n<li>Affected by DNS caching<\/li>\n\n\n\n<li>Not true real-time load balancing<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">If one server goes down, DNS may still send traffic to it unless manually removed from the zone file.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Round Robin DNS vs Traditional Load Balancers<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><div class=\"pcrstb-wrap\"><table class=\"has-fixed-layout\"><thead><tr><th>Feature<\/th><th>Round Robin DNS<\/th><th>Hardware\/Cloud Load Balancer<\/th><\/tr><\/thead><tbody><tr><td>Cost<\/td><td>Low<\/td><td>Medium to High<\/td><\/tr><tr><td>Health Checks<\/td><td>No<\/td><td>Yes<\/td><\/tr><tr><td>Real-time Failover<\/td><td>No<\/td><td>Yes<\/td><\/tr><tr><td>Session Awareness<\/td><td>Limited<\/td><td>Advanced<\/td><\/tr><tr><td>Setup Complexity<\/td><td>Simple<\/td><td>Moderate<\/td><\/tr><\/tbody><\/table><\/div><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Round Robin DNS is ideal for basic traffic distribution but not for high-availability enterprise setups.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">When Should You Use Round Robin DNS?<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Multiple web servers with identical content<\/li>\n\n\n\n<li>Geographically distributed servers<\/li>\n\n\n\n<li>Basic redundancy needs<\/li>\n\n\n\n<li>Budget-conscious hosting environments<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">It works best when combined with proper monitoring and failover strategies.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Conclusion<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Round Robin DNS is a lightweight and effective method for distributing traffic across multiple servers. While it lacks advanced health checks and real-time failover capabilities, it remains a practical solution for small to medium-sized deployments.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">By properly configuring RR-set order in BIND and optimizing TTL values, you can significantly improve traffic distribution without investing in expensive load balancing solutions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">If you require assistance configuring Round Robin DNS or optimizing your server environment, professional <a href=\"https:\/\/www.supportpro.com\/requestquote.php\" title=\"\">server administration support<\/a> can help ensure optimal performance and reliability.<\/p>\n\n\n\n<div class=\"wp-block-media-text alignwide has-media-on-the-right is-stacked-on-mobile is-vertically-aligned-center has-white-background-color has-background\"><div class=\"wp-block-media-text__content\">\n<p class=\"has-large-font-size wp-block-paragraph\">Facing issues? <\/p>\n\n\n\n<p class=\"has-large-font-size wp-block-paragraph\">Our technical support<br>engineers can solve it. <\/p>\n\n\n\n<!--HubSpot Call-to-Action Code --><span class=\"hs-cta-wrapper\" id=\"hs-cta-wrapper-3350a795-db50-482f-9911-301930d1b1be\"><span class=\"hs-cta-node hs-cta-3350a795-db50-482f-9911-301930d1b1be\" id=\"hs-cta-3350a795-db50-482f-9911-301930d1b1be\"><!--[if lte IE 8]><div id=\"hs-cta-ie-element\"><\/div><![endif]--><a href=\"https:\/\/cta-redirect.hubspot.com\/cta\/redirect\/2725694\/3350a795-db50-482f-9911-301930d1b1be\" ><img decoding=\"async\" class=\"hs-cta-img\" id=\"hs-cta-img-3350a795-db50-482f-9911-301930d1b1be\" style=\"border-width:0px;\" src=\"https:\/\/no-cache.hubspot.com\/cta\/default\/2725694\/3350a795-db50-482f-9911-301930d1b1be.png\"  alt=\"Contact Us today!\"\/><\/a><\/span><script charset=\"utf-8\" src=\"https:\/\/js.hscta.net\/cta\/current.js\"><\/script><script type=\"text\/javascript\"> hbspt.cta.load(2725694, '3350a795-db50-482f-9911-301930d1b1be', {\"useNewLoader\":\"true\",\"region\":\"na1\"}); <\/script><\/span><!-- end HubSpot Call-to-Action Code -->\n<\/div><figure class=\"wp-block-media-text__media\"><img fetchpriority=\"high\" decoding=\"async\" width=\"904\" height=\"931\" src=\"https:\/\/www.supportpro.com\/blog\/wp-content\/uploads\/2022\/09\/Free-server-checkup.png\" alt=\"guy server checkup\" class=\"wp-image-12943 size-full\" srcset=\"https:\/\/www.supportpro.com\/blog\/wp-content\/uploads\/2022\/09\/Free-server-checkup.png 904w, https:\/\/www.supportpro.com\/blog\/wp-content\/uploads\/2022\/09\/Free-server-checkup-291x300.png 291w, https:\/\/www.supportpro.com\/blog\/wp-content\/uploads\/2022\/09\/Free-server-checkup-768x791.png 768w, https:\/\/www.supportpro.com\/blog\/wp-content\/uploads\/2022\/09\/Free-server-checkup-585x602.png 585w\" sizes=\"(max-width: 904px) 100vw, 904px\" \/><\/figure><\/div>\n","protected":false},"excerpt":{"rendered":"<p>When you need to distribute website traffic across multiple servers without investing in a hardware or cloud load balancer, Round Robin DNS offers a simple and cost-effective solution. It is&hellip;<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_lmt_disableupdate":"","_lmt_disable":"","footnotes":""},"categories":[5,6,1],"tags":[],"class_list":["post-1521","post","type-post","status-publish","format-standard","hentry","category-general-topics","category-linux-basics","category-miscellaneous"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.supportpro.com\/blog\/wp-json\/wp\/v2\/posts\/1521","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.supportpro.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.supportpro.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.supportpro.com\/blog\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/www.supportpro.com\/blog\/wp-json\/wp\/v2\/comments?post=1521"}],"version-history":[{"count":6,"href":"https:\/\/www.supportpro.com\/blog\/wp-json\/wp\/v2\/posts\/1521\/revisions"}],"predecessor-version":[{"id":15906,"href":"https:\/\/www.supportpro.com\/blog\/wp-json\/wp\/v2\/posts\/1521\/revisions\/15906"}],"wp:attachment":[{"href":"https:\/\/www.supportpro.com\/blog\/wp-json\/wp\/v2\/media?parent=1521"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.supportpro.com\/blog\/wp-json\/wp\/v2\/categories?post=1521"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.supportpro.com\/blog\/wp-json\/wp\/v2\/tags?post=1521"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}