The FreeBSD Diary |
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nmap - the port scanner
10 August 1998
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| This has to be the easiest port I've ever installed! Or is it just that I'm getting to know how to do it? |
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Port scanner? What's a port scanner?
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| A port scanner doesn't check for software. Don't confuse this with a FreeBSD
port. A port scanner checks the [service] ports on a host to see what services the host is willing to provide. For example, SMTP, HTTP, etc. It is a common method to find out what can be exploited on that host. Using a port scanner is a good way to find out is turned on/off for a particular host. You can also use it to help verify that your firewall restrictions are what you think they are. |
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Which scanner?
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| I chose to install nmap as found in the FreeBSD Security ports. Don't
forget the nmap homepage. The software can be downloaded from ftp://ftp.freebsd.org/pub/FreeBSD/FreeBSD-current/ports/security/nmap.tar. |
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The install
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| Well, I followed the instructions found in the FreeBSD handbook for compiling ports from
the internet. And it ran. First time. To get you started, try issuing the following command: nmap -v localhost That should show you all the ports available on your machine. |