Some further reading… https://docs.oracle.com/javase/8/docs/technotes/guides/net/articles/connection_release.html
-Chris. > On 13 Jul 2016, at 21:37, Dmitry Samersoff <dmitry.samers...@oracle.com> > wrote: > > Christoph, > > My $0.2 > > Typically you see RST packet when the data come to a *closed* socket. > You shouldn't get RST if client/server communication shutdown properly. > > Also balancer may take a care about connection shutdown (it needs to > update internal tables) so it's possible that you never get RST after > balancer. > > Moreover, there are RST based attack and scanning methods so firewall > might be set to reject RST packets and doesn't pass it to inside network. > > I.e. IMHO, customer server should be updated to live without RST. > > -Dmitry > > On 2016-07-13 18:29, Langer, Christoph wrote: >> Hi folks, >> >> >> >> I have a question to the experts - regarding an issue that was reported >> to me by a customer. >> >> >> >> In the customer scenario they are running a Servlet engine and the >> Servlet is constantly sending data to a browser client. When the browser >> client is closed, the server does not get a notification of the other >> end having been terminated and is constantly sending out data and >> blocking an application thread. I’m under the assumption that the server >> should get an RST packet from the network upon writing/flushing data to >> the OutputStream as soon as the client is gone and hence an Exception >> should pop up but this isn’t happening. >> >> >> >> There is a load balancer and maybe other network infrastructure involved >> in between the Servlet JVM and the browser client. We did some TCPDUMP >> tracing at the load balancer and we could not see an RST packet coming >> in from the client side. But when I’m running the scenario without all >> this network infrastructure involved, e.g. between servers and clients >> in the same network, I would always observe an RST packet once I close >> the browser. A FIN packet is received, too, but this does not lead to an >> Exception and to all my knowledge this can’t be detected, not from the >> java Socket API and even less from the Servlet API which is just dealing >> with Streams. >> >> >> >> So my question to the experts is most of all: Would you agree that an >> RST packet should be generated in the network and received by the >> server? Or is it a normal behavior that servers must deal with not >> receiving RSTs and hence needing to wait for a timeout until e.g. the >> load balancer generates an RST? Also, is there any way to detect a FIN >> in the JVM and react on it? >> >> >> >> Thanks in advance and best regards >> >> Christoph >> >> >> > > > -- > Dmitry Samersoff > Oracle Java development team, Saint Petersburg, Russia > * I would love to change the world, but they won't give me the sources.
