January 2018
Intermediate to advanced
376 pages
8h 45m
English
Content preview from Mastering Linux Security and Hardening
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Port states
An Nmap scan will show the target machine's ports in one of three states:
- filtered: This means that the port is blocked by a firewall
- open: This means that the port is not blocked by a firewall and that the service that's associated with that port is running
- closed: This means that the port is not blocked by a firewall, and that the service that's associated with that port is not running
So, in our scan of the Apple machine, we see that the Secure Shell service is ready to accept connections on port 22, that the print service is ready to accept connections on ports 515 and 631, and that the Virtual Network Computing (VNC) service is ready to accept connections on port 5900. All of these ports would be of interest to a security-minded ...