Hi, I use the Boost ASIO library to send TCP packets of about 500k every minute to a TCP server. I run my application on Windows XP, the server runs on a UNIX station. I use boost 1.35 While this works well initially, eventually after 4 or 5h the call to boost::asio::write() never returns, and locks my thread. No exception is generated. I checked the RAM resources on my computer when this happens and it looks like it's stable (I don't think there is any memory leak). If I were to speculaate on this, I woudl say it looks like the call suddently becomes blocking for some reason. this being either a TCP stack being full, or no answer from the server... Any help will be greatly appreciated. Thanks! Jean