[Techtalk] How to block ports
vtrucs at gmail.com
Mon May 19 12:43:18 UTC 2008
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.
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