[stunnel-users] FD_SETSIZE still an option in stunnel 4.34?

Saikat Chakrabarti saikat at gomockingbird.com
Thu Nov 4 00:28:39 CET 2010

Hey Mike,

Thanks so much for your help.  As you suspected, the output of stunnel
-version says Sockets:POLL.  I'm digging through my stunnel logs now,
and it mostly seems normal, though I have a lot of lines that look
like this:

Nov  3 23:21:25 gomockingbird stunnel: LOG5[26463:3061513104]:
connect_blocking: connected

My setup is that I have a Node.js service running on that IP address
on port 80, and I have stunnel running on the same IP address on port
443 (this is my config: https://gist.github.com/661891 -
sing.gomockingbird.com resolves to the IP above).  I have very
long-lasting connections as I'm routing websockets/long-polling
connections via stunnel.

Am I right in thinking that this line suggests that my Node.js is
dropping the connections?

Thanks again for the help!

On Wed, Nov 3, 2010 at 2:20 AM, Michal Trojnara
<Michal.Trojnara at mirt.net> wrote:
> Saikat Chakrabarti wrote:
>> 1) Does FD_SETSIZE still exist in Stunnel 4.34 and could it be a
>> reason why I am seeing a limit on the number of people that can make a
>> connection?
> FD_SETSIZE is only used with select() on Unix.
> Execute "stunnel -version" and check the output for "Sockets:POLL" or
> "Sockets:SELECT".
>> I already tried running stunnel after setting ulimit -Hn
>> and ulimit -Sn to 4096, and it did not seem to make a difference.
> You reached a resource limit.  You should rather check your logs for error
> message in order to identify the resource and increase the limit.
> You could read:
> http://www.cs.uwaterloo.ca/~brecht/servers/openfiles.html
>> 2) More noobish question - how do I set the FD_SETSIZE at compile
>> time?  I saw in the troubleshooting that it said to do
>> "-DFD_SETSIZE=4096" at compile time.  Is this something I should be
>> adding in one of the Makefiles?
> You don't need to do it.  It's possible on some operating systems, but
> there's no portable way to do it.  Stunnel uses poll() instead of select()
> since version 4.06 (released Dec 2004).
>> Linux gomockingbird.com #1 SMP Tue Nov 10 16:12:12
>> UTC 2009 i686 GNU/Linux
> stunnel.mirt.net is also a linode.  8-)
> Best regards,
>    Mike
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