network security related question

[Vitorio Okio]

> In addition to reading those, install portsentry, which will allow you
> to specify precisely which ports you wish to monitor, up to and
> including the entire 65,000 some ports. [although monitoring all of them
> is probably overkill] To learn how to configure and use portsentry see
> "man portsentry", "man portsentry.conf", and take a look at the files in
>  /usr/share/doc/portsentry/ as well to get more insight into it's usage.
> They are in .gz files but it's easy to open them temporarily with file
> roller and view them.

Thanks for this, I've never heard of it.