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

[Jochen Strohbeck]

Hello Indan,

> Mostly TCP_MSL. But even better would be to let the client
> close the connection first.

In Wireshark I see that after the data transfer the client sends out
FIN+ACK and the http server responds only with ACK, no further FIN sent
out by the server.

Is this considered a 'half closed connection'?
Do you think the server also close the connection too in order to avoid
the RST on a 'pending connection'?

> The port re-use should not add much extra delay, the RST is sent
> immediately. Only if you ran out of sockets because they are all
> hogged for TIME WAIT will you get extra delay.

The problem is that the client application gets an CONNECTION_TIMEOUT
error if RST happens. How to distinguish the 'RST on pending connection'
from a 'server unreachable' error?

Thanks,
Jochen