Re: [libmicrohttpd] Sockets remain in CLOSE_WAIT state

[Christian Grothoff]

Hi Santos,

CLOSE_WAIT is a TCP state in the kernel after a TCP connection is
finished. It typically lasts like 60--300s, depending on your kernel
configuration (you may want to read up on the TCP state machine).
You can change the time by changing
/proc/sys/net/ipv4/tcp_fin_timeout, but usually this is not an issue
(unless you have _way_ too many TCP connections from the same host, I've
only seen this matter on loopback, in which case usually enabling
keep-alive on the client-side helps).

Summary: this is not an issue in MHD, likely not one for anyone, just a
TCP artifact.

Happy hacking!

-Christian

On 1/4/19 6:29 PM, Santos Das wrote:
> Hi Christian,
> 
> Please note I am using suspend-resume and not
> implementing MHD_OPTION_NOTIFY_CONNECTION to close . Not sure when the
> library closes the connection after it receives FIN and move to CLOSE_WAIT.
> 
> Any pointers?
> 
> thanks, santos
> 
> On Fri, Jan 4, 2019 at 10:27 PM Santos Das <address@hidden
> <mailto:address@hidden>> wrote:
> 
>     Hi Christian,
> 
>     Wishing you a happy new year!
> 
>     We have set the MHD_OPTION_CONNECTION_TIMEOUT to 0 and we see that
>     all the connections remain in CLOSE_WAIT state. 
> 
>     We also have set the MHD_OPTION_CONNECTION_LIMIT to 1000 .
> 
>     Any idea what could be wrong ?
> 
>     Thanks, Santos
>

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