TCP Deep Dive: From Packets to Byte Streams – MTU, MSS, and Proxy Chaining
If you come from a packet-forwarding background, MTU and MSS behave nothing like you expect once traffic enters a proxy chain. There is no fragmentation — only re-segmentation of a continuous byte stream. This deep dive untangles the mental model mismatch and explains why manually tuning MSS on intermediate proxies rarely does what you think it does.