NewsForge: Port Scanning and Nmap 3.5

“Inspired by the release of Nmap 3.5, the latest version of the
award-winning network security tool, I’ve been exploring network
security issues for a couple of weeks now. Nmap’s major skill is
port scanning–learning which ports on a machine are ‘open’ and
what applications are using them. Sound network security planning
dictates that you take a look at your network machines to see what
the bad guys can see from outside.

“Think of a port as being an extension of a machine’s IP
address. The IP address itself equates to a street address for an
apartment complex. The port number equates to a specific apartment.
When packets are sent across the Internet, they include the port
number they are destined for as well as the machine address…”

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