Topic

UDP

1 post about UDP. Every summary links to the original.

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Posts

Fly.io
BPF, XDP, Packet Filters and UDP
Deploying unmodified UDP applications across an anycast edge and worker network is harder than proxying HTTP, because UDP carries no convenient metadata for forwarding the original socket addresses. The initial implementation used userland services, AF_PACKET sockets, and custom proxying, but the post argues that kernel-level packet handling is a better fit than adding and monitoring another service. It explains BPF’s evolution into eBPF, then describes using XDP for fast ingress processing, XDP_REDIRECT around WireGuard limitations, and TC BPF on the worker side; Firecracker tap devices make reply traffic appear as host ingress. The verifier requires bounds checks and debugging benefits from dropwatch and perf-based packet tracing. The result is a beta deployment path for UDP applications on Fly.io.

The best engineering reads, once a week.

Topic

1 post about UDP. Every summary links to the original.

Paid picks we use ourselves. Links carry a referral code — a subscription through one earns us a commission at no extra cost to you.

Newest first

Fly.io
BPF, XDP, Packet Filters and UDP
Deploying unmodified UDP applications across an anycast edge and worker network is harder than proxying HTTP, because UDP carries no convenient metadata for forwarding the original socket addresses. The initial implementation used userland services, AF_PACKET sockets, and custom proxying, but the post argues that kernel-level packet handling is a better fit than adding and monitoring another service. It explains BPF’s evolution into eBPF, then describes using XDP for fast ingress processing, XDP_REDIRECT around WireGuard limitations, and TC BPF on the worker side; Firecracker tap devices make reply traffic appear as host ingress. The verifier requires bounds checks and debugging benefits from dropwatch and perf-based packet tracing. The result is a beta deployment path for UDP applications on Fly.io.

The best engineering reads, once a week.