{"id":1371,"date":"2026-09-30T13:23:56","date_gmt":"2026-09-30T09:23:56","guid":{"rendered":"https:\/\/www.buildingtheitguy.com\/?p=1371"},"modified":"2026-09-30T16:11:17","modified_gmt":"2026-09-30T12:11:17","slug":"juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues","status":"publish","type":"post","link":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/","title":{"rendered":"Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">I recently lost hours troubleshooting this exact scenario. You have perfectly good switches, brand new DAC cables, and solid transceivers yet the link stays stubbornly down. It is enough to drive any network engineer crazy and make you second-guess your hardware.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In the spirit of building &#8220;Calm IT Operations&#8221;<sup><\/sup> and eliminating the drama from troubleshooting<sup><\/sup>, I am documenting this. The root cause is surprisingly simple. I am sharing this real-world fix<sup><\/sup> so you do not have to waste your time pulling cables or opening support tickets. Here is exactly how to bypass the headache and bring your uplinks online in seconds.<\/p>\n\n\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: xml; title: ; notranslate\" title=\"\">\n+---------------------+           +---------------------+\n| Juniper EX4300-48P  |           | Juniper EX4600-40F  |\n|      (PIC 1)        |           |      (PIC 0)        |\n|                     |           |                     |\n|  &#x5B;et-0\/1\/0]         |  &lt;-----&gt;  |         &#x5B;et-0\/0\/24] |\n|  (QSFP+ 40G)        | 40G DAC   |       (QSFP+ 40G)   |\n|                     |  Cable    |                     |\n+---------------------+           +---------------------+\n\n<\/pre><\/div>\n\n\n<h3 class=\"wp-block-heading\">The Problem: Your 40G Link Is Down, But It Shouldn&#8217;t Be<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">You&#8217;ve connected two Juniper EX-Series switches perhaps a core EX4600 and an access EX4300 with a 40G QSFP+ Direct Attach Copper (DAC) cable. The physical connections are solid, and the configuration looks right. Yet, when you check the interface status, the link remains stubbornly down.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This can be a frustrating puzzle, often leading engineers to suspect a faulty cable or hardware. However, a common and often overlooked culprit is a mismatch in <strong>auto-negotiation<\/strong>. This post will guide you through the symptoms and provide a simple, effective fix.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Symptoms and Diagnosis<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">You&#8217;ll know you&#8217;re facing this issue when a simple <code>show interfaces terse<\/code> command reveals a port that is &#8220;up&#8221; administratively but &#8220;down&#8221; physically.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">On the EX4300:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: bash; title: ; notranslate\" title=\"\">\nroot@ASATH-Spine-SW01&gt; show interfaces et-0\/1\/0 terse\nInterface               Admin Link Proto    Local                 Remote\net-0\/1\/0                up    down\net-0\/1\/0.0              up    down eth-switch\n\n<\/pre><\/div>\n\n\n<p class=\"wp-block-paragraph\">On the EX4600 (Core):<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: bash; title: ; notranslate\" title=\"\">\nroot@ASATH-LAB-CORE# run show interfaces et-0\/0\/24 terse\nInterface               Admin Link Proto    Local                 Remote\net-0\/0\/24               up    down\net-0\/0\/24.0             up    down eth-switch\n\n<\/pre><\/div>\n\n\n<p class=\"wp-block-paragraph\">You might also see &#8220;Incomplete&#8221; or similar messages in the auto-negotiation status when you run an extensive interface check.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">The Simple Fix: Disable Auto-Negotiation<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The reason for the link failure is that some DAC cables, even official Juniper ones, can be particular about how they handle auto-negotiation. In a direct QSFP+ connection between two fixed-speed devices, auto-negotiation is often unnecessary and can actually introduce a point of failure.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">By disabling auto-negotiation and manually setting the speed to 40G on both ends, you force the link to establish without any negotiation handshake.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Step 1: Identify the Ports<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">Ensure you are targeting the correct 40G interfaces on each switch. In our example, that&#8217;s <code>et-0\/1\/0<\/code> on the EX4300 and <code>et-0\/0\/24<\/code> on the EX4600.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Step 2: Configure the EX4300<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">In configuration mode, run the following commands:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: bash; title: ; notranslate\" title=\"\">\nset interfaces et-0\/1\/0 ether-options no-auto-negotiation\nset interfaces et-0\/1\/0 ether-options speed 40g\ncommit\n\n<\/pre><\/div>\n\n\n<h4 class=\"wp-block-heading\"><strong>Step 3: Configure the EX4600<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">Repeat the process on the core switch:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: bash; title: ; notranslate\" title=\"\">\nset interfaces et-0\/0\/24 ether-options no-auto-negotiation\nset interfaces et-0\/0\/24 ether-options speed 40g\ncommit\n\n<\/pre><\/div>\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Verification and Best Practices<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">After committing the changes on both switches, the physical link should come up instantly.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Run <code>show interfaces terse<\/code> again to confirm:<\/p>\n\n\n<div class=\"wp-block-syntaxhighlighter-code \"><pre class=\"brush: bash; title: ; notranslate\" title=\"\">\nroot@ASATH-Spine-SW01&gt; show interfaces et-0\/1\/0 terse\nInterface               Admin Link Proto    Local                 Remote\net-0\/1\/0                up    up\net-0\/1\/0.0              up    up   eth-switch\n\n<\/pre><\/div>\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><td><strong>Do This<\/strong><\/td><td><strong>Avoid This<\/strong><\/td><\/tr><\/thead><tbody><tr><td><strong>Document<\/strong> manual speed settings.<\/td><td>Forgetting to apply the fix to <strong>both ends<\/strong>.<\/td><\/tr><tr><td><strong>Use<\/strong> certified transceivers\/cables.<\/td><td>Assuming the cable is bad before troubleshooting.<\/td><\/tr><tr><td><strong>Match<\/strong> speed settings on both sides exactly.<\/td><td>Missing the underlying auto-negotiation issue.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>I recently lost hours troubleshooting this exact scenario. You have perfectly good switches, brand new DAC cables, and solid transceivers yet the link stays stubbornly down. It is enough to drive any network engineer crazy and make you second-guess your hardware. In the spirit of building &#8220;Calm IT Operations&#8221; and eliminating the drama from troubleshooting, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":1395,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[102],"tags":[],"class_list":["post-1371","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-it-infrastructure"],"featured_image_src":"https:\/\/www.buildingtheitguy.com\/wp-content\/uploads\/2026\/09\/Juniper-SW-40G-DAC.jpg","author_info":{"display_name":"Mohamed Asath","author_link":"https:\/\/www.buildingtheitguy.com\/index.php\/author\/asathwebtieradmin\/"},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.6 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues - Building THE IT GUY<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues - Building THE IT GUY\" \/>\n<meta property=\"og:description\" content=\"I recently lost hours troubleshooting this exact scenario. You have perfectly good switches, brand new DAC cables, and solid transceivers yet the link stays stubbornly down. It is enough to drive any network engineer crazy and make you second-guess your hardware. In the spirit of building &#8220;Calm IT Operations&#8221; and eliminating the drama from troubleshooting, [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/\" \/>\n<meta property=\"og:site_name\" content=\"Building THE IT GUY\" \/>\n<meta property=\"article:published_time\" content=\"2026-09-30T09:23:56+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2026-09-30T12:11:17+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.buildingtheitguy.com\/wp-content\/uploads\/2026\/09\/Juniper-SW-40G-DAC.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"1200\" \/>\n\t<meta property=\"og:image:height\" content=\"628\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"author\" content=\"Mohamed Asath\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Mohamed Asath\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"3 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/\"},\"author\":{\"name\":\"Mohamed Asath\",\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/#\\\/schema\\\/person\\\/cce03fcda4c40ccf57ab3844ca707561\"},\"headline\":\"Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues\",\"datePublished\":\"2026-09-30T09:23:56+00:00\",\"dateModified\":\"2026-09-30T12:11:17+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/\"},\"wordCount\":444,\"commentCount\":0,\"image\":{\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/Juniper-SW-40G-DAC.jpg\",\"articleSection\":[\"IT Infrastructure\"],\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/\",\"url\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/\",\"name\":\"Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues - Building THE IT GUY\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/Juniper-SW-40G-DAC.jpg\",\"datePublished\":\"2026-09-30T09:23:56+00:00\",\"dateModified\":\"2026-09-30T12:11:17+00:00\",\"author\":{\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/#\\\/schema\\\/person\\\/cce03fcda4c40ccf57ab3844ca707561\"},\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/#primaryimage\",\"url\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/Juniper-SW-40G-DAC.jpg\",\"contentUrl\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/wp-content\\\/uploads\\\/2026\\\/09\\\/Juniper-SW-40G-DAC.jpg\",\"width\":1200,\"height\":628,\"caption\":\"Quick fix for Juniper EX-Series 40G DAC uplinks: disable auto-negotiation and set speed to 40g on both ends.\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\\\/it-infrastructure\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/#website\",\"url\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/\",\"name\":\"Building THE IT GUY\",\"description\":\"Making Everyone&#039;s Life Easier\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/#\\\/schema\\\/person\\\/cce03fcda4c40ccf57ab3844ca707561\",\"name\":\"Mohamed Asath\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/ab17cc6285a5051affe4181f53011c89cc055de9416bcc44b3e2771be318d870?s=96&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/ab17cc6285a5051affe4181f53011c89cc055de9416bcc44b3e2771be318d870?s=96&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/ab17cc6285a5051affe4181f53011c89cc055de9416bcc44b3e2771be318d870?s=96&r=g\",\"caption\":\"Mohamed Asath\"},\"description\":\"Turning IT Challenges into Opportunities\",\"sameAs\":[\"https:\\\/\\\/www.buildingtheitguy.com\"],\"url\":\"https:\\\/\\\/www.buildingtheitguy.com\\\/index.php\\\/author\\\/asathwebtieradmin\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues - Building THE IT GUY","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/","og_locale":"en_US","og_type":"article","og_title":"Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues - Building THE IT GUY","og_description":"I recently lost hours troubleshooting this exact scenario. You have perfectly good switches, brand new DAC cables, and solid transceivers yet the link stays stubbornly down. It is enough to drive any network engineer crazy and make you second-guess your hardware. In the spirit of building &#8220;Calm IT Operations&#8221; and eliminating the drama from troubleshooting, [&hellip;]","og_url":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/","og_site_name":"Building THE IT GUY","article_published_time":"2026-09-30T09:23:56+00:00","article_modified_time":"2026-09-30T12:11:17+00:00","og_image":[{"width":1200,"height":628,"url":"https:\/\/www.buildingtheitguy.com\/wp-content\/uploads\/2026\/09\/Juniper-SW-40G-DAC.jpg","type":"image\/jpeg"}],"author":"Mohamed Asath","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Mohamed Asath","Est. reading time":"3 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/#article","isPartOf":{"@id":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/"},"author":{"name":"Mohamed Asath","@id":"https:\/\/www.buildingtheitguy.com\/#\/schema\/person\/cce03fcda4c40ccf57ab3844ca707561"},"headline":"Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues","datePublished":"2026-09-30T09:23:56+00:00","dateModified":"2026-09-30T12:11:17+00:00","mainEntityOfPage":{"@id":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/"},"wordCount":444,"commentCount":0,"image":{"@id":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/#primaryimage"},"thumbnailUrl":"https:\/\/www.buildingtheitguy.com\/wp-content\/uploads\/2026\/09\/Juniper-SW-40G-DAC.jpg","articleSection":["IT Infrastructure"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/","url":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/","name":"Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues - Building THE IT GUY","isPartOf":{"@id":"https:\/\/www.buildingtheitguy.com\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/#primaryimage"},"image":{"@id":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/#primaryimage"},"thumbnailUrl":"https:\/\/www.buildingtheitguy.com\/wp-content\/uploads\/2026\/09\/Juniper-SW-40G-DAC.jpg","datePublished":"2026-09-30T09:23:56+00:00","dateModified":"2026-09-30T12:11:17+00:00","author":{"@id":"https:\/\/www.buildingtheitguy.com\/#\/schema\/person\/cce03fcda4c40ccf57ab3844ca707561"},"breadcrumb":{"@id":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/#primaryimage","url":"https:\/\/www.buildingtheitguy.com\/wp-content\/uploads\/2026\/09\/Juniper-SW-40G-DAC.jpg","contentUrl":"https:\/\/www.buildingtheitguy.com\/wp-content\/uploads\/2026\/09\/Juniper-SW-40G-DAC.jpg","width":1200,"height":628,"caption":"Quick fix for Juniper EX-Series 40G DAC uplinks: disable auto-negotiation and set speed to 40g on both ends."},{"@type":"BreadcrumbList","@id":"https:\/\/www.buildingtheitguy.com\/index.php\/juniper-ex-series-the-quick-fix-for-40g-dac-uplink-issues\/it-infrastructure\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.buildingtheitguy.com\/"},{"@type":"ListItem","position":2,"name":"Juniper EX-Series: The Quick Fix for 40G DAC Uplink Issues"}]},{"@type":"WebSite","@id":"https:\/\/www.buildingtheitguy.com\/#website","url":"https:\/\/www.buildingtheitguy.com\/","name":"Building THE IT GUY","description":"Making Everyone&#039;s Life Easier","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.buildingtheitguy.com\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/www.buildingtheitguy.com\/#\/schema\/person\/cce03fcda4c40ccf57ab3844ca707561","name":"Mohamed Asath","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/ab17cc6285a5051affe4181f53011c89cc055de9416bcc44b3e2771be318d870?s=96&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/ab17cc6285a5051affe4181f53011c89cc055de9416bcc44b3e2771be318d870?s=96&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/ab17cc6285a5051affe4181f53011c89cc055de9416bcc44b3e2771be318d870?s=96&r=g","caption":"Mohamed Asath"},"description":"Turning IT Challenges into Opportunities","sameAs":["https:\/\/www.buildingtheitguy.com"],"url":"https:\/\/www.buildingtheitguy.com\/index.php\/author\/asathwebtieradmin\/"}]}},"_links":{"self":[{"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/posts\/1371","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/comments?post=1371"}],"version-history":[{"count":2,"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/posts\/1371\/revisions"}],"predecessor-version":[{"id":1399,"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/posts\/1371\/revisions\/1399"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/media\/1395"}],"wp:attachment":[{"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/media?parent=1371"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/categories?post=1371"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.buildingtheitguy.com\/index.php\/wp-json\/wp\/v2\/tags?post=1371"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}