--- title: Your router still depends on a 44-year-old protocol to... description: Address Resolution Protocol (ARP), developed in 1982, still underpins how home routers map IP addresses to MAC addresses on most IPv4 networks. It works by... canonical: https://daily.dev/posts/your-router-still-depends-on-a-44-year-old-protocol-to-locate-every-device-on-your-network-imka9mnej twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Your router still depends on a 44-year-old protocol to locate every device on your network | daily.dev og:description: Address Resolution Protocol (ARP), developed in 1982, still underpins how home routers map IP addresses to MAC addresses on most IPv4 networks. It works by... og:url: https://daily.dev/posts/your-router-still-depends-on-a-44-year-old-protocol-to-locate-every-device-on-your-network-imka9mnej og:image: https://api.daily.dev/og/posts/IMkA9MNej.png og:image:alt: Your router still depends on a 44-year-old protocol to locate every device on your network 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. # Your router still depends on a 44-year-old protocol to locate every device on your network **[XDA Developers](https://daily.dev/sources/xda-developers)** · 3 min read · 0 upvotes · 0 comments ## Summary Address Resolution Protocol (ARP), developed in 1982, still underpins how home routers map IP addresses to MAC addresses on most IPv4 networks. It works by broadcasting requests and replies with no authentication, making it vulnerable to ARP spoofing and man-in-the-middle attacks, though HTTPS limits the real-world impact on encrypted traffic. IPv6 replaces ARP with Neighbor Discovery Protocol, and enabling client/AP isolation can mitigate spoofing risk at the cost of breaking local device discovery features like smart home control and wireless printing. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What does ARP actually do on a home network? Address Resolution Protocol maps a device's IP address (Layer 3) to its physical MAC address (Layer 2) so a router knows where to physically deliver data packets. Routers keep an ARP table of these IP-to-MAC pairs. Devices broadcast an ARP request asking who owns a given IP, and the matching device replies with its MAC address. _Understanding core protocols like ARP helps when debugging local network issues, a topic developers track on daily.dev._ ### Why is ARP considered insecure? ARP has no built-in authentication, so any device on a network can falsely claim to own an IP address when replying to a request. This lack of verification enables ARP spoofing or cache poisoning, which can lead to man-in-the-middle attacks. HTTPS encryption limits the damage for most traffic, but older unencrypted smart home devices like cameras and plugs remain exposed to eavesdropping. _Developers securing local networks can follow protocol-level vulnerabilities like this on daily.dev._ ### Does IPv6 use ARP for address resolution? No, IPv6 replaces ARP with Neighbor Discovery Protocol (NDP). Most home networks remain heavily IPv4-dependent, which is why ARP, despite dating back to 1982, is still the protocol handling IP-to-MAC address mapping for the majority of home traffic. _Anyone planning an IPv4-to-IPv6 transition can keep up with networking fundamentals on daily.dev._ ## Similar posts on daily.dev - [When ARP Goes Wrong: Threat Hunting ARP Poisoning in Network Traffic](https://daily.dev/posts/when-arp-goes-wrong-threat-hunting-arp-poisoning-in-network-traffic-cr9xr7c4h) · InfoSec Write-ups · 1 upvotes · 0 comments - [Your router's MAC address filter is security theater, and here's what actually protects your Wi-Fi](https://daily.dev/posts/your-router-s-mac-address-filter-is-security-theater-and-here-s-what-actually-protects-your-wi-fi-xhciw5dun) · XDA Developers · 0 upvotes · 0 comments - [The world in which IPv6 was a good design](https://daily.dev/posts/the-world-in-which-ipv6-was-a-good-design-tj3i8ov0s) · Hacker News · 0 upvotes · 0 comments - [I ignored IPv6 for years, and now my home network is paying the price](https://daily.dev/posts/i-ignored-ipv6-for-years-and-now-my-home-network-is-paying-the-price-yp8jivhal) · XDA Developers · 0 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#networking](https://daily.dev/tags/networking) [View this post on daily.dev](https://daily.dev/posts/your-router-still-depends-on-a-44-year-old-protocol-to-locate-every-device-on-your-network-imka9mnej) ```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":"Your router still depends on a 44-year-old protocol to locate every device on your network","url":"https://daily.dev/posts/your-router-still-depends-on-a-44-year-old-protocol-to-locate-every-device-on-your-network-imka9mnej","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/your-router-still-depends-on-a-44-year-old-protocol-to-locate-every-device-on-your-network-imka9mnej"},"datePublished":"2026-08-24T14:00:39.429Z","dateModified":"2026-08-24T14:03:29.931Z","description":"Address Resolution Protocol (ARP), developed in 1982, still underpins how home routers map IP addresses to MAC addresses on most IPv4 networks. 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