This generally is an application issue (look at SO_LINGER for example). The client is not receiving the CLOSE_WAIT confirmation from the server and thus leaving the socket open or visa versa. May also (rarely) be caused by settings in network routers and switches which limit packet size. Do a Web search - lots of information on this issue out there on the Internet.

You should be able to use sysctl to manage this issue until you figure out which application is causing the problem.