[[nmap]]
`nmap` - Port Scans
-------------------

`nmap` is designed to allow system administrators to scan large
networks, to determine which hosts are up and what services they
offer. You can use nmap to test your firewall settings, for example,
to see if the required ports are open.

.Test Razor port (tcp port 2703):
----
# nmap -P0 -sS -p 2703 c301.cloudmark.com
Starting Nmap 7.70 ( https://nmap.org ) at 2020-04-14 12:20 CEST
Nmap scan report for c301.cloudmark.com (208.83.137.114)
Host is up (0.13s latency).

PORT     STATE SERVICE
2703/tcp open  sms-chat

Nmap done: 1 IP address (1 host up) scanned in 6.83 seconds
----

For more information about `nmap` usage, see the
https://nmap.org/book/man.html[Nmap Reference Guide], also available as a manual
page (`man nmap`).
