we have a product called jintegra: it's a bridge between DCOM and java. The java part runs as a jar in a webapp on websphere 18.104.22.168 on AIX 5.3 (so it's J2RE 1.4.2 IBM AIX build ca1420-20040626) Works fine most of the time, but occasionally the listener (netstat -an) indicates that the listener is gone...(and telnet won't work either) Established connections continue to work properly. A restart of the application server resolves the the situation. Anyone seen behavior like that in a java app??? Analysing thread dumps suggests that the thread running ServerSocketInstance.accept has not stopped. Could this be an OS-jdk thing?