I don't mean to be a swaggerer, but, i just need to correct a small part of the *excellent* piece by Kishor :-)
There is one important file..called /etc/services, that lists all the services your box is offering to the outside world.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Actually, the "/etc/services" file simply lists the ports and protocol names. Its purpose is to provide mappings between the protocol names like telnet, ftp etc., to their respective port numbers. It *does not* mean that the services are actually running.
Pleeease, please, please *do not feel hurt*, Kishor, since that is not my aim. I am sorry if you feel otherwise. In any case, thank you for taking the initiative to start the discussion :-))
Fart