[Techtalk] How to block ports

[Vonda]

Kai MacTane wrote:
> When I want to know what's open on a system I admin, I just nmap it. You 
> can get nmap from http://nmap.org/ (big surprise, huh?). You might want 
> to to be careful about running it against other people's machines, since 
> this program *is* a port-scanner, but running it against your own 
> machine is not a problem.
>
> Note that "nmap localhost" or "nmap 127.0.0.1" may bypass your firewall 
> (if you have one) and show you services that are running, but which have 
> been firewalled so that nobody else in the world can reach them. Whereas 
> "nmap your.fully.qualified.domain.name" or "nmap your.public.ip.address" 
> will show you what the rest of the world sees.
>
>                                                  --Kai MacTane
>   

Very useful to know.   I heard rumors that my office's network admins 
will severely sanction anyone who portmaps, but this is nice to know for 
my home network and just in general. 


Vonda