[stunnel-users] problem with buffering data on stunnel

Thu Jul 9 11:53:20 CEST 2015

	I have a problem with transmission from LAN server, which use another 
server

	on LAN with running stunnel, to pass encrypted data to remote SSL clients

	if they are on very slow GPRS network. If server in LAN starts to transfer

	big amount of data to such slow remote client, stunnel is buffering data 
and

	slowly transmits them to the GPRS client. TCP Window on connection from LAN

	server to stunnel is big (64 - 131kB), and TCP Window on connection from

	stunnel to slow client is small (about 5kB). And additionally stunnel is

	buffering data. So, server is finishing transmission in seconds, but in 
fact

	most of data are still in buffers of stunnel. And it makes a timeout 
problem

	(server is waiting for the confirmation from client if it received all data,
	but time between last byte sent from server and confirmation from client

	could be even several minutes).

	
	So, stunnel is working in "store and forward" model. Is it possible to

	switch it to something like "cut through"? Or how to force stunnel to more

	synchronized transmission between client and server?


	Regards,


	Adalbert
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