--- title: Interface EBGP Sessions on Arista EOS « ipSpace.net blog description: A step-by-step configuration guide for setting up interface EBGP sessions on Arista EOS (release 4.31.2F), filling a gap in available documentation. The guide... canonical: https://daily.dev/posts/interface-ebgp-sessions-on-arista-eos-ipspace-net-blog-rceurgzj1 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Interface EBGP Sessions on Arista EOS « ipSpace.net blog | daily.dev og:description: A step-by-step configuration guide for setting up interface EBGP sessions on Arista EOS (release 4.31.2F), filling a gap in available documentation. The guide... og:url: https://daily.dev/posts/interface-ebgp-sessions-on-arista-eos-ipspace-net-blog-rceurgzj1 og:image: https://api.daily.dev/og/posts/rceUrGZj1.png og:image:alt: Interface EBGP Sessions on Arista EOS « 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. # Interface EBGP Sessions on Arista EOS « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 4 min read · 0 upvotes · 0 comments ## Summary A step-by-step configuration guide for setting up interface EBGP sessions on Arista EOS (release 4.31.2F), filling a gap in available documentation. The guide clarifies terminology — these sessions run BGP over IPv6 link-local addresses (LLA) while carrying IPv4 prefixes using RFC 8950 next hops — and walks through each required configuration step: enabling IPv6 on interfaces, enabling IPv6 unicast routing, creating a BGP peer group, specifying interface neighbors with their AS numbers, activating the IPv4 address family, and critically, adding the `neighbor ebgp next-hop address-family ipv6 originate` command so RFC 8950 next hops are negotiated. The post also clarifies when `ip routing ipv6 interfaces` is needed (hardware forwarding ASICs that don't forward IPv4 over IPv6 LLA interfaces without it), confirmed by reader feedback from production deployments. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do I configure interface EBGP sessions on Arista EOS using IPv6 link-local addresses? On Arista EOS 4.31.2F, configure interface EBGP sessions by: enabling IPv6 on each interface (`ipv6 enable`), enabling `ipv6 unicast-routing` globally, creating a BGP peer group, specifying interface neighbors with `neighbor interface Et1 peer-group ebgp remote-as `, activating the peer group for IPv4 (`neighbor ebgp activate`), and adding `neighbor ebgp next-hop address-family ipv6 originate` to negotiate RFC 8950 IPv6 next hops for IPv4 prefixes. _Network engineers deploying BGP fabrics track Arista-specific gotchas like these on daily.dev._ ### What does 'ip routing ipv6 interfaces' do on Arista EOS and when do I need it? On Arista EOS, `ip routing ipv6 interfaces` enables IPv4 forwarding over IPv6 LLA interfaces at the hardware ASIC level. Without it, transit switches running on certain hardware platforms silently blackhole IPv4 packets received over IPv6 LLA uplinks even when BGP sessions and routes appear correct. It is a hardware-platform-specific knob documented in Arista TOI EOS-4-17-0F and is not needed in virtual/cEOS environments. _Engineers running Arista hardware in production find platform-specific knobs like this faster on daily.dev._ ### Why do IPv4 BGP prefixes over an IPv6 LLA session get wrong next hops or not advertise on Arista EOS? Without the command `neighbor next-hop address-family ipv6 originate` in the IPv4 address family, Arista EOS does not negotiate RFC 8950 next hops. As a result, IPv4 prefixes sent over the IPv6 LLA BGP session either carry useless IPv4 next hops or are not advertised at all. Adding that command causes the router to use IPv6 LLA addresses as next hops for IPv4 prefixes. _Debugging BGP next-hop issues across vendors is easier when you follow routing engineers sharing real configs 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/interface-ebgp-sessions-on-arista-eos-ipspace-net-blog-rceurgzj1) ```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":"Interface EBGP Sessions on Arista EOS « ipSpace.net blog","url":"https://daily.dev/posts/interface-ebgp-sessions-on-arista-eos-ipspace-net-blog-rceurgzj1","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/interface-ebgp-sessions-on-arista-eos-ipspace-net-blog-rceurgzj1"},"datePublished":"2026-08-11T08:55:28.422Z","dateModified":"2026-08-11T09:31:38.686Z","description":"A step-by-step configuration guide for setting up interface EBGP sessions on Arista EOS (release 4.31.2F), filling a gap in available documentation. 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