Give two examples of how a service provided by a Linux serve

Give two examples of how a service provided by a Linux server to the network could be restricted in cases where the services must not be turned off.

Solution

It is perfectly possible to have a fully functional Internet connection with no servers running that are accessible to outside connections. Not only possible, but desirable in many cases. The principle here is that you will never be successfully broken into via a port that is not opened because no server is listening on it. No server == no port open == not vulnerable. At least to outside connections.

If you don\'t recognize a particular service, chances are good you don\'t really need it. We will assume that and so we\'ll turn it off. This may sound dangerous, but is a good rule of thumb to go by.

Some services are just not intended to be run over the Internet -- even if you decide it is something you really do need. We\'ll flag these as dangerous, and address these in later sections, should you decide you do really need them, and there is no good alternative.