Hi, I have posted the question here at StackForge with all the details. http://stackoverflow.com/questions/40163626/boost-asio- ssl-not-working-as-expected-when-used-with-null-buffers Basically, http://www.boost.org/doc/libs/1_40_0/doc/html/ boost_asio/overview/core/reactor.html did not work when used with ssl. With plain-tcp steam socket, it works fine. o If we do ssl_socket->lowest_layer().async_read_some(null_buffers(), read_cb), then we do get all data in read_cb, but read_cb keep getting called endlessly (and read_some then returns 0, with error 11 resource unavailable) (This causes cpu remain over-utilized for ever) If we do ssl_socket->async_read_some(null_buffers(), read_cb), then it works fine with small amounts of data. When larger data is to be received (~20MB or so), then not all data is received. around 1% of data towards the end is never received by the application. My guess is that data is sitting in openssl library some where I tried with latest ssl and boost code, but that did not help either. Can some one please help ? Thanks, Ananth