#layer4

TCP: Raising the Wrong Flags

The City, the Duke, and the Portcullis Picture a walled city. A Duke — the operating system — presides over it, though he governs less than it sounds like he might. Behind the city walls, tradespeople work their own shops: a baker, a blacksmith, an armourer, a stableman. Each is a service running on the host, reachable through its own door — a port. Visitors arrive from other cities looking to trade, and each has to pass the portcullis first, where a guard decides who gets through and who doesn’