About This Event

**Golang Birmingham is back on 8 October!** We are pleased to announce that our next **Golang Birmingham** event will take place on **Thursday, 8 October 2026**. We are delighted to welcome **Samuel Adetunji**, an experienced open-source Golang engineer, as one of our speakers for the evening. Samuel’s talk topic and full session details will be announced shortly. We are also excited to welcome **Kumbirai Tanekha**, a Principal Software Engineer at Palo Alto Networks, who will be joining us from London. ### From TAP to curl: Building a Userspace TCP Stack in Go When you call `connect()` or `curl`, the kernel quietly does a huge amount of work behind the scenes: building Ethernet frames, answering ARP, constructing IPv4 headers, and managing TCP handshakes and retransmissions. In this talk, Kumbirai will peel back those layers by building a **userspace Ethernet → IPv4 → ICMP/TCP implementation in Go**, driven by a Linux TAP device. Every read and write becomes a raw frame that we can inspect, parse and craft ourselves. The session will work through the networking stack layer by layer, exploring why TAP rather than TUN matters when working at Layer 2, how ARP turns an IP address into a real MAC address, how ICMP can be used to prove the IP path, and how to build a minimal passive TCP implementation capable of handling a handshake, in-order data, an echo or tiny HTTP server, and fixed-RTO retransmission. Kumbirai will also look at what this deliberately minimal implementation does not attempt to build, including full windowing, congestion control and routing, and why leaving those pieces out can make the fundamentals easier to understand. **The main takeaway:** TCP stops being magic and becomes a sequence of bytes that you can own, inspect and demystify, one stage at a time. ### About Kumbirai **Kumbirai Tanekha** is a seasoned Software Engineer based in London and currently works as a **Principal Software Engineer at Palo Alto Networks**. He enjoys deep diving into th

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