I am working on a Linux embedded distribution and I need to monitor incoming and outcoming connections (if they are still actives etc.) and I am experiencing issues because I noticed that, even if the remote host turn off the connection, I can see the connection as ESTABLISHED through netstat.
I have two different versions of this Linux embedded system: one which uses an old 2.6.34 kernel and it works fine, while the one which is failing uses a kernel 3.18.18.
Looking for more information I suspect I had to set/change TCP timeouts, so I configured them through syctl.conf but doesn't change anything. The system which uses 2.6.34 kernel doesn't have TCP timeouts configured, so it makes me think that TCP are not the root of my problem.
Do you have an idea about what could be the reason of the fact that the connection remain as ESTABLISHED?