--- title: Can a Router Use the Default Route to Reach BGP Next... description: RFC 4271 allows BGP next hops to be resolved via any route in the routing table, including the default route (0.0.0.0/0). A lab test across multiple platforms... canonical: https://daily.dev/posts/can-a-router-use-the-default-route-to-reach-bgp-next-hops-ipspace-net-blog-lwuzw0has twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Can a Router Use the Default Route to Reach BGP Next Hops? « ipSpace.net blog | daily.dev og:description: RFC 4271 allows BGP next hops to be resolved via any route in the routing table, including the default route (0.0.0.0/0). A lab test across multiple platforms... og:url: https://daily.dev/posts/can-a-router-use-the-default-route-to-reach-bgp-next-hops-ipspace-net-blog-lwuzw0has og:image: https://api.daily.dev/og/posts/lWuzw0hAs.png og:image:alt: Can a Router Use the Default Route to Reach BGP Next Hops? « ipSpace.net blog 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. # Can a Router Use the Default Route to Reach BGP Next Hops? « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 4 min read · 0 upvotes · 0 comments ## Summary RFC 4271 allows BGP next hops to be resolved via any route in the routing table, including the default route (0.0.0.0/0). A lab test across multiple platforms reveals different behaviors: Cisco IOSv and Arista EOS both use the default route to resolve BGP next hops (with Arista correctly displaying the route used), while Cumulus Linux/FRR does not by default and requires the explicit command `ip nht resolve-via-default` to enable this behavior. Juniper MX also uses the default route, as confirmed in comments. The key RFC 4271 rule is that a BGP route is unresolvable only when no route at all matches the next hop — the default route qualifies as a match. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### Can a router use the default route to resolve BGP next hops according to RFC 4271? Yes. RFC 4271's Route Resolvability Condition states a BGP route is unresolvable only when no route in the routing table matches its NEXT_HOP. The default route (0.0.0.0/0) qualifies as a matching route, so all BGP routes are considered valid when a default route is present. Mutually recursive routes are the only explicit exception. _Network engineers validating BGP behavior across platforms track RFC interpretations like this on daily.dev._ ### How do I enable FRR or Cumulus Linux to resolve BGP next hops via the default route? FRR and Cumulus Linux do not use the default route for BGP next-hop resolution by default, marking affected routes as inaccessible and invalid. To enable it, run `ip nht resolve-via-default` in global configuration mode. After applying this command, previously invalid BGP routes become valid and are selected as best paths. _Engineers running FRR-based routers find platform-specific BGP gotchas like this on daily.dev._ ## Similar posts on daily.dev - [The Never-Ending IPv6 Loopback Prefix Saga « ipSpace.net blog](https://daily.dev/posts/the-never-ending-ipv6-loopback-prefix-saga-ipspace-net-blog-4nlhgh10l) · ipSpace.net Blog · 0 upvotes · 0 comments --- Tags: [#bgp](https://daily.dev/tags/bgp) [View this post on daily.dev](https://daily.dev/posts/can-a-router-use-the-default-route-to-reach-bgp-next-hops-ipspace-net-blog-lwuzw0has) ```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":"Can a Router Use the Default Route to Reach BGP Next Hops? « ipSpace.net blog","url":"https://daily.dev/posts/can-a-router-use-the-default-route-to-reach-bgp-next-hops-ipspace-net-blog-lwuzw0has","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/can-a-router-use-the-default-route-to-reach-bgp-next-hops-ipspace-net-blog-lwuzw0has"},"datePublished":"2026-08-11T08:52:46.171Z","dateModified":"2026-08-11T09:05:43.809Z","description":"RFC 4271 allows BGP next hops to be resolved via any route in the routing table, including the default route (0.0.0.0/0). 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RFC 4271's Route Resolvability Condition states a BGP route is unresolvable only when no route in the routing table matches its NEXT_HOP. The default route (0.0.0.0/0) qualifies as a matching route, so all BGP routes are considered valid when a default route is present. Mutually recursive routes are the only explicit exception. Network engineers validating BGP behavior across platforms track RFC interpretations like this on daily.dev."}},{"@type":"Question","name":"How do I enable FRR or Cumulus Linux to resolve BGP next hops via the default route?","acceptedAnswer":{"@type":"Answer","text":"FRR and Cumulus Linux do not use the default route for BGP next-hop resolution by default, marking affected routes as inaccessible and invalid. To enable it, run `ip nht resolve-via-default` in global configuration mode. After applying this command, previously invalid BGP routes become valid and are selected as best paths. 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