{"id":2668,"date":"2008-03-10T17:15:57","date_gmt":"2008-03-10T23:15:57","guid":{"rendered":"http:\/\/www.conradaskland.com\/blog\/2008\/03\/maximum-dns-ttl\/"},"modified":"2009-03-06T21:30:08","modified_gmt":"2009-03-07T03:30:08","slug":"maximum-dns-ttl","status":"publish","type":"post","link":"https:\/\/conradaskland.com\/blog\/maximum-dns-ttl\/","title":{"rendered":"Maximum DNS TTL"},"content":{"rendered":"<p>A sample DNS (Domain Name Server) setting for TTL (Time to Live) might be 86400. TTL settings are entered as seconds and the max TTL time could be entered as one day like this: 60x60x24 = 86400.<\/p>\n<p><!--more--><\/p>\n<p>For instance, if you want to reduce the cached Ttl to 10 minutes. Use a MaxCacheTtl value of 600. You can also set a different value for the Maximum Negative cache (Cached answers of non-existent domain) set the MaxNegativeCacheTtl to 0, and the DNS Client cache will not cache Negative responses. Although, if you query the same DNS server again, if the non-existent domain may be still in its cache.<\/p>\n<p>All values in these entries are in seconds.<\/p>\n<p><strong>UPDATE:<\/strong> My original post here mentioned a number as the &#8220;maximum TTL value&#8221; possible. This was corrected by a poster that there is in fact no such thing as a limit to the maximum TTL value. Subsequently I found this which provides more information (from Alexander Ottl at Media Professionals AG):<\/p>\n<p><em>But there is a maximum TTL in the context of BINDs cache configuration.<br \/>\nTo quote the document:<\/em><\/p>\n<p><em><strong>max-ncache-ttl<\/strong><\/em><\/p>\n<p><em>To reduce network traffic and increase performance the server store\u00a0 negative answers.\u00a0 max-ncache-ttl is used to set a maximum retention time for these answers in the server is seconds.\u00a0 The default max-ncache-ttl is 10800 seconds (3 hours).\u00a0 max-ncache-ttl cannot exceed the maximum retention time for ordinary (positive) answers (7 days) and will be silently truncated to 7 days if set to a value which is greater than 7 days.<\/em><\/p>\n<p><em>&#8212;<br \/>\nAlexander Ottl<br \/>\nMedia Professionals AG <\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A sample DNS (Domain Name Server) setting for TTL (Time to Live) might be 86400. TTL settings are entered as seconds and the max TTL time could be entered as one day like this: 60x60x24 = 86400.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"footnotes":""},"categories":[6],"tags":[2446,2442,2436,2447,2434,2437,2433,2450,2449,2439,2443,2440,2435,2444,2451,2441,2438],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p3C0LX-H2","_links":{"self":[{"href":"https:\/\/conradaskland.com\/blog\/wp-json\/wp\/v2\/posts\/2668"}],"collection":[{"href":"https:\/\/conradaskland.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/conradaskland.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/conradaskland.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/conradaskland.com\/blog\/wp-json\/wp\/v2\/comments?post=2668"}],"version-history":[{"count":3,"href":"https:\/\/conradaskland.com\/blog\/wp-json\/wp\/v2\/posts\/2668\/revisions"}],"predecessor-version":[{"id":4026,"href":"https:\/\/conradaskland.com\/blog\/wp-json\/wp\/v2\/posts\/2668\/revisions\/4026"}],"wp:attachment":[{"href":"https:\/\/conradaskland.com\/blog\/wp-json\/wp\/v2\/media?parent=2668"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/conradaskland.com\/blog\/wp-json\/wp\/v2\/categories?post=2668"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/conradaskland.com\/blog\/wp-json\/wp\/v2\/tags?post=2668"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}