--- title: All About SUBNETTING your Networks! + Setup in OPNsense description: A practical guide covering the fundamentals of subnets and VLANs, explaining how IP addressing and prefix lengths work, how devices route traffic within and... canonical: https://daily.dev/posts/all-about-subnetting-your-networks-setup-in-opnsense-wsikn1j80 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: All About SUBNETTING your Networks! + Setup in OPNsense | daily.dev og:description: A practical guide covering the fundamentals of subnets and VLANs, explaining how IP addressing and prefix lengths work, how devices route traffic within and... og:url: https://daily.dev/posts/all-about-subnetting-your-networks-setup-in-opnsense-wsikn1j80 og:image: https://api.daily.dev/og/posts/wSIkN1J80.png og:image:alt: All About SUBNETTING your Networks! + Setup in OPNsense og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # All About SUBNETTING your Networks! + Setup in OPNsense **[apalrd's adventures](https://daily.dev/sources/apalrd)** · 4 min read · 0 upvotes · 0 comments ## Summary A practical guide covering the fundamentals of subnets and VLANs, explaining how IP addressing and prefix lengths work, how devices route traffic within and between subnets, and how IEEE 802.1Q VLANs allow multiple logically separate networks to share physical infrastructure. The guide also covers setting up subnet and VLAN interfaces in OPNsense. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the difference between a subnet and a VLAN in networking? A subnet is a logical address grouping defined by an IP prefix and length (e.g., /24), determining which hosts communicate directly vs. via a router. A VLAN (IEEE 802.1Q) is a Layer 2 mechanism that tags Ethernet frames so multiple logically separate networks can share the same physical switches and cabling, while remaining isolated from each other as if on separate hardware. _Home lab engineers sorting out network segmentation find the latest OPNsense guides on daily.dev._ ### How does a device decide whether to send traffic directly or via the default gateway? A device compares the destination IP address against its own subnet prefix. If the prefix matches, the packet is sent directly on-link and the destination MAC is resolved via ARP (IPv4) or NDP (IPv6), bypassing the router entirely. If the prefix does not match, the packet is forwarded to the default gateway, which routes it toward the correct destination. _Developers building segmented home or office networks track routing and firewall topics like this on daily.dev._ ## Similar posts on daily.dev - [Network segmentation is the smart home security step nobody talks about](https://daily.dev/posts/network-segmentation-is-the-smart-home-security-step-nobody-talks-about-0vihlne2o) · XDA Developers · 0 upvotes · 0 comments - [Add a VLAN to OPNsense in Just 26 Clicks Across 6 Screens](https://daily.dev/posts/add-a-vlan-to-opnsense-in-just-26-clicks-across-6-screens-qerabobc9) · Lobsters · 1 upvotes · 0 comments - [5 rules I use for sane VLAN design at home \(without overcomplicating it\)](https://daily.dev/posts/5-rules-i-use-for-sane-vlan-design-at-home-without-overcomplicating-it--3wvgbumjq) · XDA Developers · 0 upvotes · 1 comments - [Computer Networks Explained: The Complete Guide](https://daily.dev/posts/computer-networks-explained-the-complete-guide-uozado4ud) · Medium · 0 upvotes · 0 comments --- Tags: [#networking](https://daily.dev/tags/networking) [View this post on daily.dev](https://daily.dev/posts/all-about-subnetting-your-networks-setup-in-opnsense-wsikn1j80) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"All About SUBNETTING your Networks! + Setup in OPNsense","url":"https://daily.dev/posts/all-about-subnetting-your-networks-setup-in-opnsense-wsikn1j80","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/all-about-subnetting-your-networks-setup-in-opnsense-wsikn1j80"},"datePublished":"2026-08-11T08:56:20.920Z","dateModified":"2026-08-11T09:31:13.456Z","description":"A practical guide covering the fundamentals of subnets and VLANs, explaining how IP addressing and prefix lengths work, how devices route traffic within and...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/84f4bcc716e8a98d15431e7da71792c2?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/84f4bcc716e8a98d15431e7da71792c2?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"apalrd's adventures","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"apalrd's adventures","logo":"https://media.daily.dev/image/upload/s--4zkx8dRj--/f_auto,q_auto/v1786438309/logos/apalrd?_a=BAMAMicg0","url":"https://daily.dev/sources/apalrd"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/all-about-subnetting-your-networks-setup-in-opnsense-wsikn1j80","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"networking","timeRequired":"PT4M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"apalrd's adventures","item":"https://daily.dev/sources/apalrd"},{"@type":"ListItem","position":3,"name":"All About SUBNETTING your Networks! + Setup in OPNsense"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/all-about-subnetting-your-networks-setup-in-opnsense-wsikn1j80#faq","mainEntity":[{"@type":"Question","name":"What is the difference between a subnet and a VLAN in networking?","acceptedAnswer":{"@type":"Answer","text":"A subnet is a logical address grouping defined by an IP prefix and length (e.g., /24), determining which hosts communicate directly vs. via a router. 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