hi..

we have the following setup

to java process communicating by sockets with each other, and another one on an external machine.

from time to time, there seem to be "outages" where one process is unable to communicate with the other, the simply indicate things like "connection refused" exceptions, and while it seems the processes themselves are mis-behaving i'm not sure that is the case.

how can i know for sure the a tcp packet sent from one process (at least in the same machine) was received by another process and vice versa ? that it wasn't blocked by anything else?
i think IPTABLES has this log feature , but not sure how to use it.

try LOG target and the matched packets will have traces in syslog (most likely /var/log/syslog)

i'm sorta of a noob in linux?