Socket programing Permission denied

Question

Following code is TCP server program just send back “HELLO!!” to client.

When I run server with port 80, bind() is returned Permission denied.

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Answer 1

Only the root user is allowed to bind to ports <= 1024. Every ports > 1024 can be bound to by normal users.

Try executing your program as root or with sudo.

Answer 2

you have to run your application with super user account (root)

Run your application with sudo command

Answer 3

Ports below 1024 are considered "privileged" and can only be bound to with an equally privileged user (read: root).

Anything above and including 1024 is "free to use" by anyone.

OT: you may know this already, but the port in your example is that for HTTP web servers. Anything listening to this port should speak HTTP, too. A simple "hello world" does not suffice. ;-)