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.

P

Answer 1

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. ;-)