{"id":449,"date":"2026-04-16T21:07:02","date_gmt":"2026-04-16T21:07:02","guid":{"rendered":"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/?page_id=449"},"modified":"2026-04-16T21:24:23","modified_gmt":"2026-04-16T21:24:23","slug":"dns-resolution-failure-network-troubleshooting-lab-lab","status":"publish","type":"page","link":"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/dns-resolution-failure-network-troubleshooting-lab-lab\/","title":{"rendered":"DNS Resolution Failure &amp; Network Troubleshooting Lab Lab"},"content":{"rendered":"\n<h3 class=\"wp-block-heading\">Overview<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Problem Encountered<\/strong><\/h4>\n\n\n\n<blockquote class=\"wp-block-quote\">\n<p>During setup, DNS queries failed across multiple devices, preventing access to websites despite having active internet connectivity.<\/p>\n<\/blockquote>\n\n\n\n<p>In this project, I set up a Pi-hole DNS server on a Raspberry Pi to provide network-wide ad blocking and DNS visibility. While configuring the system, I encountered DNS resolution issues and troubleshot them by analyzing DNS queries, testing upstream resolvers, and identifying a router-level DNS interception conflict.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>What I Did<\/strong><\/h2>\n\n\n\n<ul>\n<li>Configured a Raspberry Pi as a local DNS server using Pi-hole<\/li>\n\n\n\n<li>Routed DNS traffic through a GL.iNet (Beryl 7) router<\/li>\n\n\n\n<li>Used tools like dig, nslookup, and ping to test connectivity<\/li>\n\n\n\n<li>Identified DNS failures (REFUSED responses) when querying external DNS servers<\/li>\n\n\n\n<li>Discovered router-level DNS interception caused by DNS override settings<\/li>\n\n\n\n<li>Resolved the issue by identifying and disabling router-level DNS interception caused by DNS override settings<\/li>\n\n\n\n<li>Verified functionality by successfully resolving domains and restoring access to websites<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\" \/>\n\n\n\n<h2 class=\"wp-block-heading\">Troubleshooting Process<\/h2>\n\n\n\n<p>During this project, I followed a structured troubleshooting approach to isolate the root cause of the DNS failure. I first verified network connectivity using ICMP (ping), confirming that the issue was not related to internet access. I then tested DNS resolution directly against external resolvers using dig and observed REFUSED responses, indicating that DNS queries were being blocked before reaching upstream servers.<\/p>\n\n\n\n<blockquote class=\"wp-block-quote\">\n<blockquote class=\"wp-block-quote\">\n<blockquote class=\"wp-block-quote\">\n<p>By comparing results across multiple resolvers (Cloudflare and Google DNS), I determined that the issue was not specific to a single provider. This led me to investigate network-level configurations, where I identified that the router was intercepting DNS traffic due to an enabled DNS override setting.<\/p>\n\n\n\n<p>After disabling this feature, I restored proper DNS flow through the Pi-hole server and verified successful resolution using dig, confirming that upstream communication had been restored.<\/p>\n<\/blockquote>\n<\/blockquote>\n<\/blockquote>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\" \/>\n\n\n\n<h2 class=\"wp-block-heading\">Key Skills<\/h2>\n\n\n\n<ul>\n<li>DNS troubleshooting<\/li>\n\n\n\n<li>Network configuration<\/li>\n\n\n\n<li>Linux command-line tools<\/li>\n\n\n\n<li>Problem-solving and debugging<\/li>\n\n\n\n<li>Understanding DNS resolution flow<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\" \/>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Tools &amp; Technologies<\/strong><\/h2>\n\n\n\n<ul>\n<li>Raspberry Pi<\/li>\n\n\n\n<li>Pi-hole<\/li>\n\n\n\n<li>Linux<\/li>\n\n\n\n<li>GL.iNet Router (Beryl 7)<\/li>\n\n\n\n<li>Cloudflare DNS (1.1.1.1)<\/li>\n\n\n\n<li>dig, nslookup, ping<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\" \/>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>What I Learned<\/strong><\/h2>\n\n\n\n<blockquote class=\"wp-block-quote\">\n<p>This project helped me understand how DNS resolution works across devices, routers, and local services. I learned how misconfigurations at the router level can interfere with DNS traffic and how to systematically troubleshoot and resolve those issues.<\/p>\n<\/blockquote>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><a href=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-6.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"982\" src=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-6-1024x982.png\" alt=\"\" class=\"wp-image-450\" style=\"width:847px;height:auto\" srcset=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-6-1024x982.png 1024w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-6-300x288.png 300w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-6-768x736.png 768w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-6-833x799.png 833w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-6-192x184.png 192w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-6.png 1280w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n\n\n\n<p>Pi-hole dashboard showing DNS traffic, query activity, and filtering statistics across connected clients<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\" \/>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-7.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"925\" src=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-7-1024x925.png\" alt=\"\" class=\"wp-image-451\" srcset=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-7-1024x925.png 1024w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-7-300x271.png 300w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-7-768x694.png 768w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-7-833x752.png 833w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-7-192x173.png 192w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-7.png 1343w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n\n\n\n<p>Query log displaying DNS requests and filtering behavior, used to analyze traffic and identify issues<\/p>\n\n\n\n<blockquote class=\"wp-block-quote\">\n<hr class=\"wp-block-separator has-alpha-channel-opacity\" \/>\n<\/blockquote>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-8.png\"><img loading=\"lazy\" decoding=\"async\" width=\"713\" height=\"491\" src=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-8.png\" alt=\"\" class=\"wp-image-452\" srcset=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-8.png 713w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-8-300x207.png 300w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-8-192x132.png 192w\" sizes=\"(max-width: 713px) 100vw, 713px\" \/><\/a><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote\">\n<p>Successfully resolved DNS queries after disabling router-level DNS interception and restoring proper upstream resolution<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\" \/>\n<\/blockquote>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-11.png\"><img loading=\"lazy\" decoding=\"async\" width=\"977\" height=\"947\" src=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-11.png\" alt=\"\" class=\"wp-image-455\" srcset=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-11.png 977w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-11-300x291.png 300w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-11-768x744.png 768w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-11-833x807.png 833w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-11-192x186.png 192w\" sizes=\"(max-width: 977px) 100vw, 977px\" \/><\/a><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote\">\n<p>Verified successful DNS resolution using dig after restoring proper upstream DNS communication<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\" \/>\n<\/blockquote>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-12.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"738\" src=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-12-1024x738.png\" alt=\"\" class=\"wp-image-456\" srcset=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-12-1024x738.png 1024w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-12-300x216.png 300w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-12-768x553.png 768w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-12-833x600.png 833w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-12-192x138.png 192w, https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-content\/uploads\/sites\/38223\/2026\/04\/image-12.png 1206w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/a><\/figure>\n\n\n\n<blockquote class=\"wp-block-quote\">\n<p>Router DNS configuration showing disabled DNS override to prevent interception and allow proper upstream DNS resolution through Pi-hole<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\" \/>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>Overview Problem Encountered During setup, DNS queries failed across multiple devices, preventing access to websites despite having active internet connectivity. In this project, I set up a Pi-hole DNS server on a Raspberry Pi to provide network-wide ad blocking and DNS visibility. While configuring the system, I encountered DNS resolution issues and troubleshot them by &hellip; <a href=\"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/dns-resolution-failure-network-troubleshooting-lab-lab\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">DNS Resolution Failure &amp; Network Troubleshooting Lab Lab<\/span><\/a><\/p>\n","protected":false},"author":30417,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"_links":{"self":[{"href":"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-json\/wp\/v2\/pages\/449"}],"collection":[{"href":"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-json\/wp\/v2\/users\/30417"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-json\/wp\/v2\/comments?post=449"}],"version-history":[{"count":2,"href":"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-json\/wp\/v2\/pages\/449\/revisions"}],"predecessor-version":[{"id":465,"href":"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-json\/wp\/v2\/pages\/449\/revisions\/465"}],"wp:attachment":[{"href":"https:\/\/sites.wp.odu.edu\/eriksorto-portfolio\/wp-json\/wp\/v2\/media?parent=449"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}