Nmap
From charlesreid1
How To Use
Nmap is a really really complicated tool, so consult the extensive manual to really use it properly.
The Man Page
$ man nmap
The Short Version
You run nmap like this:
Usage: nmap [Scan Type(s)] [Options] {target specification}
If you read through the manual, it is organized this way:
- first, target specification is covered
- then, increasingly intrusive levels of scan type are described in order
- within each chapter on a scan type, the different options are described
Basic Network Scan
The Host Discovery section (http://nmap.org/book/man-host-discovery.html) starts by covering basic host discovery, with least intrusive first. In this case, a list lookup doesn't even send packets to the specified addresses, it just does a dns lookup on them.
nmap -sL 10.0.0.0/24
The target specification section (http://nmap.org/book/man-target-specification.html) covers what the ip address range above means, and I'll explain here too. The trailing /24 means, all permutations of the last 24 bits (that is, 0-254, the normal range of IP addresses).