Hello, after a long time without writing, I finally found the time.
And in another tutorial, we’ll learn how discover open ports or closed on a server, computer …
For this task, we use the command nmap .
According to nmap’s own description, the application is:
Nmap (“Network Mapper”) is an open source tool for network exploration and security auditing. It was designed to track (Scan) large networks quickly yet works well with a single host (host). Nmap uses raw IP packets in (raw) on new ways to determine what hosts (hosts) are available on the net …
For more details you can find in http://nmap.org/ . I like to use nmap, but it does not mean that this is the only way to accomplish this task.
Listing the main server ports
The simplest of commands, just run nmap to the server that you want to investigate
Listing the main server ports in more detail
nmap -s test.com
Verifying several machines on the network
Very useful for network administrators
Check certain ips
nmap 192.168.254.1 192.168.254.2 192.168.254.3
Verifying a track (one range) of IP’s
Verifying a range using wildcard
Verifying a specific port
nmap -p [port] test.com
Verifying a range of ports
nmap -p 80-400 test.com
Again, this is not the only method of doing this scan. And you can find more about nmap the link: http://www.cyberciti.biz/networking/nmap-command-examples-tutorials/