--- title: Inside the Packet: How Kubernetes Networking Actually... description: A deep technical walkthrough of how Kubernetes networking actually works at the packet level, traced through a live cluster using tcpdump, ip route,... canonical: https://daily.dev/posts/inside-the-packet-how-kubernetes-networking-actually-works-at-l3-l4-mlktkkrux twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Inside the Packet: How Kubernetes Networking Actually Works at L3/L4 | daily.dev og:description: A deep technical walkthrough of how Kubernetes networking actually works at the packet level, traced through a live cluster using tcpdump, ip route,... og:url: https://daily.dev/posts/inside-the-packet-how-kubernetes-networking-actually-works-at-l3-l4-mlktkkrux og:image: https://api.daily.dev/og/posts/MLkTKKRUX.png og:image:alt: Inside the Packet: How Kubernetes Networking Actually Works at L3/L4 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. # Inside the Packet: How Kubernetes Networking Actually Works at L3/L4 **[Container Journal](https://daily.dev/sources/container_journal)** · 7 min read · 1 upvotes · 0 comments ## Summary A deep technical walkthrough of how Kubernetes networking actually works at the packet level, traced through a live cluster using tcpdump, ip route, iptables-save, conntrack, and bpftool. Covers the full dataplane path: Pod network namespaces and veth pairs, the cni0 Linux bridge for same-node Pod-to-Pod traffic, and cross-node routing via VXLAN overlay (Flannel/Calico), BGP native routing (Calico), and eBPF/XDP (Cilium). Explains how kube-proxy implements Service ClusterIPs using DNAT and iptables probability chains, the scaling problem at 2,000+ Services (48,000+ rules evaluated linearly), and why large clusters switch to IPVS or Cilium eBPF. Includes a debugging toolkit (ip route, conntrack, tcpdump), a section on DNS as the hidden cause of 80% of networking issues with NodeLocal DNSCache as the fix, NetworkPolicy enforcement differences between Calico and Cilium, and a decision matrix for choosing between iptables, IPVS, and eBPF based on cluster scale. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Kubernetes Networking Explained: From ClusterIP to Cilium Service Mesh](https://daily.dev/posts/kubernetes-networking-explained-from-clusterip-to-cilium-service-mesh-rhwqkcwdn) · freeCodeCamp · 4 upvotes · 0 comments - [Medium](https://daily.dev/posts/medium-wddx69mmc) · Medium · 0 upvotes · 0 comments - [Understanding Kubernetes Networking](https://daily.dev/posts/understanding-kubernetes-networking-oooxha7or) · cilium · 22 upvotes · 1 comments --- Tags: [#linux](https://daily.dev/tags/linux), [#kubernetes](https://daily.dev/tags/kubernetes) [View this post on daily.dev](https://daily.dev/posts/inside-the-packet-how-kubernetes-networking-actually-works-at-l3-l4-mlktkkrux) ```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":"Inside the Packet: How Kubernetes Networking Actually Works at L3/L4","url":"https://daily.dev/posts/inside-the-packet-how-kubernetes-networking-actually-works-at-l3-l4-mlktkkrux","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/inside-the-packet-how-kubernetes-networking-actually-works-at-l3-l4-mlktkkrux"},"datePublished":"2026-07-10T13:27:11.959Z","dateModified":"2026-07-10T13:27:37.574Z","description":"A deep technical walkthrough of how Kubernetes networking actually works at the packet level, traced through a live cluster using tcpdump, ip route,...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/1ae2c02e3a1d1aa9202e5b8fd9a6b8e6?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/1ae2c02e3a1d1aa9202e5b8fd9a6b8e6?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Container Journal","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":"Container Journal","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/45be8dbd2bbe4dd6ac35de519c6e4cd2","url":"https://daily.dev/sources/container_journal"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/inside-the-packet-how-kubernetes-networking-actually-works-at-l3-l4-mlktkkrux","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":1},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"linux,kubernetes","timeRequired":"PT7M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Container Journal","item":"https://daily.dev/sources/container_journal"},{"@type":"ListItem","position":3,"name":"Inside the Packet: How Kubernetes Networking Actually Works at L3/L4"}]} ```