Re: [lwip-users] Unusual termination of a TCP connection.

[Simon Goldschmidt]

Roger Cover wrote:
> Thank you all for your replies.

No answer often means noone knows what your problem is.

> [..] the lwIP 1.2.0 server always sends ACKs for the request (GET or POST)
> packets before sending the data requested. [..]
> The lwIP 1.4.1 server sends the requested data before sending ACKs for the 
> request.

I don't know exactly (the 1.2.0 release was even before my active time in lwIP)
but I guess there has been an optimization after 1.2.0 to not send the ACK as a
seperate packet. Instead, the ACK should piggy-back on the response data 
segment.
And this is what I see in my servers, too.

You say are seeing the data before the ACK but from reading 'lwip141.pcapng',
the server does exactly what I said in the last paragraph.

However, I see a strang usage of HTTP: your server responds with HTTP 1.0 but 
does
not add a connection header. This means the server should close the connection,
not the client. In this case, it's OK for the server to respond with RST.

This might however still not be a sufficient explanation of why the RST is sent
or what you could do to prevent it being sent.


Simon