Re: connecting an unbound socket to itself

[Serge Belyshev]

changed subject to highlight the issue.

David Stevens <dlstevens@xxxxxxxxxx> writes:

>  > But nothing was listen()'ing on the port and nothing accept()'ed the
>> connection.
>> 
>> If you had similar code running on two different machines, each of which
>> attempted connections to the other machine, I would expect that they
>> would never connect because of the asymetric nature of the TCP SYN,
>> SYN/ACK, ACK connection sequence.
>
> You don't have to listen to do a connect. Two programs (on different
> machines or not) that are doing cross connects works, too.
>
>                                                         +-DLS

But my socket is unbound and I'm connecting to a loopback address, so
I expect the connection to fail if nobody listens on the port I am
connecting to.  Yet the connections succeedes on the rare occasion when
the kernel chooses the source port number that matches the destination.
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