Re: [lwip-users] ACK missing after SYN, strange high Ack Num

[Jochen Strohbeck]

Hello Indan,

> I think the key here is "TCP Port numbers reused". If you open and close
> many TCP connections to the same host MS Windows will re-used a recently
> used port which is still in the CLOSE WAIT state on lwIP's side.

You're probably right. The faster requests are sent, the more likely
that a port number is reused more often and shorter intervals.

Do you know which timeout value is responsible for keeping recently used
port numbers?


> The behaviour you see here is expected and no one is doing anything wrong
> (It's fine to use random ports and occasionally re-use recent ones, as
> long as the error is not propagated to the application).

That's another story I am not sure who is right or wrong here.
For my testing I'm using Python requests which is doing up to 3 retries,
which may cause an probably unwanted long delay in the response if
retries are done in case the above port reuse problem occurs.