1

I have a socket server under Python:

sock= socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setblocking(0)
sock.bind((self._ipadress, port))

later I'm accepting incoming requests in a loop, using select.select:

connection, client_address = sock.accept()
...
select.select(...)

Note that connections can be closed by clients when they not need it anymore.

I tested my code with a python client and was able to observe that multiple connections can be easily handled simultaneously as expected.

However, very sporadically I get error:

“Only one usage of each socket address is normally permitted”

What does it tell me and when does it happen?

Multiple connections on the same port are definitely possible (I tested it), so why should there be only one usage permitted? This is against the principle, that multiple clients can be accepted by the same server.

I learned from

Python server "Only one usage of each socket address is normally permitted"

that it can be avoided by using SO_REUSEADDR. But why is it required, since even after closing a connection by a client, the socket should still be able to accept other connections. Otherwise my program wouldn't work at all.

I'm at home now and not in the office, so I cannot test it, but I have even problems to understand the principles behind...

.

MichaelW
  • 1,328
  • 1
  • 15
  • 32
  • Maybe you have logic that will restart your server at some error condition? Then the sock.bind bit would (potentially) cause that... – C. Gonzalez Nov 18 '18 at 20:06
  • hmmm. I think I can rule out that bind is called a second time for a given port. Did you mean that? – MichaelW Nov 18 '18 at 20:18

0 Answers0