title: What is the minimum SO_RCVBUF value?
body: <p>To minimize latency (I don't care about packet loss) I want the smallest possible receive buffer for UDP. However, when I set SO_RCVBUF to below 1000 (with setsockopt), my program never receives any packets. The datagrams I am sending have 28 bytes of data, for a total on-wire packet size of 70 bytes, so why can I not receive anything if SO_RCVBUF is &lt; 1000? And how do I change this, to allow a smaller buffer size?</p>
  
  <p>Additionally, is it possible to set the buffer in terms of number of packets, rather than bytes? Or is there some way I can manually empty it?</p>