[lwip-users] Re: [lwip] CLOSE_WAIT

[Adam Dunkels]

Hi

On Saturday 20 October 2001 22:27, you wrote:
> Any idea's why the linux server (192.168.0.1) doesn't close the connectcion
> (I use the telnet port on in uIP (192.168.0.128) to echo the incoming data)
> Here's the tcpdump result.

[...]

> Netstat give me for this connection :
> Proto Recv-Q Send-Q Local Address           Foreign Address         State
> tcp        0      0 petbox.be:1050          192.168.0.128:telnet
> CLOSE_WAIT
>
> Any idea's ??

The reason for this is that the Linux program hans't called close() on the 
socket. In TCP, connections can be half-closed such that data still can be 
transmitted in the direction that hasn't been closed. A connection in 
FIN_WAIT_1 indicates that the local side has been closed, but the other end 
hasn't been closed yet, and a connection is CLOSE_WAIT indicates that the 
local endpoint of the connection hans't been closed.

This is also the reason why the Linux server hasn't sent a FIN. 

Are you running telnet to access your 6809 board or have you written a 
special Linux program for doing the communication? Telnet *should* close the 
connection if the remote host closes it.

/adam
-- 
Adam Dunkels <address@hidden>
http://www.sics.se/~adam
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