[erlang-questions] misunderstanding of TCP/IP in a gen_server

[Michael Santos]

On Tue, Dec 21, 2010 at 05:06:07PM +0100, info wrote:
> Hello,
> I have a problem of TCP/IP understanding.
> I set the socket server like this:
> Opts = [binary, 
>              {reuseaddr, true},
>              {backlog,5}, 
>   {packet, 0},  
>   {active, false},
>              {nodelay, true}], 
> 
> and, after the listen and the accept, I do:
> 
> case gen_tcp:recv(Socket, 0) of
>         {ok, Data} ->
> 
> I monitor the TCP/IP frames and I see (client  ->  server):
> AP ->               
> <- AF 
> ->  A
> ->  AR
> 
> I don't understand why the server set the flag "F". The consequence is the reset (AR) by the client.

Difficult to say without seeing the code, but the process holding the
accepted socket is probably crashing and Erlang is closing the socket
(hence the FIN).