problem with buffering data on stunnel
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
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Adalbert, My guess would be: socket = l:SO_RCVBUF=2048 socket = r:SO_SNDBUF=2048 Mike On 09.07.2015 11:53, wujot wrote:
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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participants (2)
-
Michal Trojnara -
wujot