--- title: I ran double NAT for two years without knowing it, and... description: Running two routers in router mode simultaneously creates double NAT, a hidden network configuration issue that silently breaks port forwarding, smart home... canonical: https://daily.dev/posts/i-ran-double-nat-for-two-years-without-knowing-it-and-fixing-it-explained-problems-i-d-blamed-on-ev-oszktqcm5 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: I ran double NAT for two years without knowing it, and fixing it explained problems I'd blamed on everything else | daily.dev og:description: Running two routers in router mode simultaneously creates double NAT, a hidden network configuration issue that silently breaks port forwarding, smart home... og:url: https://daily.dev/posts/i-ran-double-nat-for-two-years-without-knowing-it-and-fixing-it-explained-problems-i-d-blamed-on-ev-oszktqcm5 og:image: https://api.daily.dev/og/posts/oszktqCm5.png og:image:alt: I ran double NAT for two years without knowing it, and fixing it explained problems I'd blamed on everything else 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. # I ran double NAT for two years without knowing it, and fixing it explained problems I'd blamed on everything else **[XDA Developers](https://daily.dev/sources/xda-developers)** · 4 min read · 0 upvotes · 0 comments ## Summary Running two routers in router mode simultaneously creates double NAT, a hidden network configuration issue that silently breaks port forwarding, smart home device discovery, remote access, and self-hosted services while leaving everyday browsing and streaming unaffected. After two years of misdiagnosing symptoms — blaming ISP throttling, Wi-Fi congestion, and upload speeds — a traceroute revealed two private IP hops before reaching a public address. Switching the secondary ASUS router from router mode to access point mode immediately resolved five separate problems: RustDesk relay fallback, Immich backup timeouts, Jellyfin remote buffering, Vaultwarden unreachability, and Home Assistant device dropouts. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is double NAT and how do I check if my home network has it? Double NAT occurs when two routers on the same network both perform network address translation, usually because a second router was left in default router mode instead of being switched to access point mode. It can be confirmed by running a traceroute from a device connected to the second router and checking whether the first two hops land on private IP ranges before reaching a public address. _Anyone troubleshooting flaky remote access or smart home connectivity can dig into networking fixes like this on daily.dev._ ### What problems can double NAT cause on a home network with smart home and self-hosted services? Double NAT can cause Home Assistant devices to fail discovery, Immich mobile backups to time out, Jellyfin remote streams to buffer, RustDesk to fall back to relay connections instead of connecting directly, and Vaultwarden to become unreachable from outside the network, even though ordinary browsing and streaming keep working fine. _Self-hosters chasing intermittent remote-access bugs can find networking deep dives like this through daily.dev._ ### How do I fix double NAT caused by a second router at home? Switch the second router from default router mode into access point mode so it stops issuing its own DHCP leases and performing a second layer of NAT on top of the primary router. This single setting change can resolve multiple unrelated-seeming issues at once, since services behind the second router no longer fight an extra translation layer. _Homelab builders wiring up extra routers can track practical fixes like this on daily.dev._ ## Similar posts on daily.dev - [Double NAT: The silent killer of your home network's performance](https://daily.dev/posts/double-nat-the-silent-killer-of-your-home-network-s-performance-67z2fkcdx) · XDA Developers · 0 upvotes · 0 comments - [I turned on IPv6 to future-proof my network, and it quietly wrecked my latency](https://daily.dev/posts/i-turned-on-ipv6-to-future-proof-my-network-and-it-quietly-wrecked-my-latency-f75enl4hp) · XDA Developers · 1 upvotes · 0 comments - [I run two routers at home, and it's not for the reason you think](https://daily.dev/posts/i-run-two-routers-at-home-and-it-s-not-for-the-reason-you-think-ncrzwctj0) · XDA Developers · 0 upvotes · 0 comments - [Self-Hosting Behind CGNAT](https://daily.dev/posts/self-hosting-behind-cgnat-lrdls1bcr) · Lobsters · 1 upvotes · 0 comments - [I used an old router as a dedicated smart home network, and it solved two problems at once](https://daily.dev/posts/i-used-an-old-router-as-a-dedicated-smart-home-network-and-it-solved-two-problems-at-once-vogsqytyh) · XDA Developers · 0 upvotes · 0 comments --- Tags: [#networking](https://daily.dev/tags/networking) [View this post on daily.dev](https://daily.dev/posts/i-ran-double-nat-for-two-years-without-knowing-it-and-fixing-it-explained-problems-i-d-blamed-on-ev-oszktqcm5) ```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":"I ran double NAT for two years without knowing it, and fixing it explained problems I'd blamed on everything else","url":"https://daily.dev/posts/i-ran-double-nat-for-two-years-without-knowing-it-and-fixing-it-explained-problems-i-d-blamed-on-ev-oszktqcm5","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/i-ran-double-nat-for-two-years-without-knowing-it-and-fixing-it-explained-problems-i-d-blamed-on-ev-oszktqcm5"},"datePublished":"2026-07-27T17:31:13.570Z","dateModified":"2026-09-13T21:20:04.523Z","description":"Running two routers in router mode simultaneously creates double NAT, a hidden network configuration issue that silently breaks port forwarding, smart home...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/3d84292bdac164a40561eb5e81d9408d?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/3d84292bdac164a40561eb5e81d9408d?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"XDA Developers","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":"XDA Developers","logo":"https://media.daily.dev/image/upload/s--kCg6yyAP--/f_auto,q_auto/v1774964407/logos/xda-developers?_a=BAMAMiWQ0","url":"https://daily.dev/sources/xda-developers"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/i-ran-double-nat-for-two-years-without-knowing-it-and-fixing-it-explained-problems-i-d-blamed-on-ev-oszktqcm5","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":"XDA Developers","item":"https://daily.dev/sources/xda-developers"},{"@type":"ListItem","position":3,"name":"I ran double NAT for two years without knowing it, and fixing it explained problems I'd blamed on everything else"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/i-ran-double-nat-for-two-years-without-knowing-it-and-fixing-it-explained-problems-i-d-blamed-on-ev-oszktqcm5#faq","mainEntity":[{"@type":"Question","name":"What is double NAT and how do I check if my home network has it?","acceptedAnswer":{"@type":"Answer","text":"Double NAT occurs when two routers on the same network both perform network address translation, usually because a second router was left in default router mode instead of being switched to access point mode. It can be confirmed by running a traceroute from a device connected to the second router and checking whether the first two hops land on private IP ranges before reaching a public address. Anyone troubleshooting flaky remote access or smart home connectivity can dig into networking fixes like this on daily.dev."}},{"@type":"Question","name":"What problems can double NAT cause on a home network with smart home and self-hosted services?","acceptedAnswer":{"@type":"Answer","text":"Double NAT can cause Home Assistant devices to fail discovery, Immich mobile backups to time out, Jellyfin remote streams to buffer, RustDesk to fall back to relay connections instead of connecting directly, and Vaultwarden to become unreachable from outside the network, even though ordinary browsing and streaming keep working fine. Self-hosters chasing intermittent remote-access bugs can find networking deep dives like this through daily.dev."}},{"@type":"Question","name":"How do I fix double NAT caused by a second router at home?","acceptedAnswer":{"@type":"Answer","text":"Switch the second router from default router mode into access point mode so it stops issuing its own DHCP leases and performing a second layer of NAT on top of the primary router. This single setting change can resolve multiple unrelated-seeming issues at once, since services behind the second router no longer fight an extra translation layer. Homelab builders wiring up extra routers can track practical fixes like this on daily.dev."}}]} ```