Why do some servers have TCP/UDP alongside the port they're listening to. To my understanding TCP and UDP are socket layers, they're methods of determining how the traffic is being sent over the network, so why would this be relevant when sending a request to a server. The port number should represent the process such as FTP, and when the client connects I should be able to choose TCP or UDP, depending on how I want the data transferred.

So why so some ports force a socket layer protocol?

closed as off-topic by multithr3at3d, AndrolGenhald, Steffen Ullrich, schroeder Nov 10 '18 at 8:50

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question does not appear to be about Information security within the scope defined in the help center." – multithr3at3d, AndrolGenhald, Steffen Ullrich, schroeder
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  • In order to bind to a port, you first need to have determined whether you are using TCP or UDP. If you look at socket programming, you first create the socket by choosing which protocol to use. Then, you actually bind to it and start listening. – multithr3at3d Nov 10 '18 at 2:18
  • I like your answer, but I can't give you reputation if you leave it as a comment :) – J.Doe Nov 10 '18 at 3:02

Your understanding is flawed.

"Ports" are virtual. They exist above IP. A TCP port and a UDP port are two completely isolated things. It's not like there are just 2 << 16 available ports to be shared around.

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