add cloud info

CloudComputing_Lab/modules/ROOT/pages/c.adoc

@@ -11,10 +11,20 @@ TIP: Create VPN
 video::565597681[vimeo,start=1 ]
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-== Find All IP Addresses on a Network
+== Find All IP Addresses and used ports on a Network
+
+On modern operating systems, ports are numbered addresses for network traffic. Different kinds of services use different ports by default.
+
+For example, normal web traffic uses Port 80, while POP3 email uses Port 110. One of the ways that a firewall works is by allowing or restricting traffic over a particular port.
+
+Because the ports into your computer can cause a security risk, it’s critical to know which ports are open and which are blocked.
 
 http://docs.swarmlab.io/SwarmLab-HowTos/swarmlab/docs/build/site/swarmlab_sec-intro/docs/index.html[Network Scanning]
 
+Nmap, short for Network Mapper, is a free, open-source tool for vulnerability scanning and network discovery. Network administrators use Nmap to identify what devices are running on their systems, discovering hosts that are available and the services they offer, finding open ports and detecting security risks.
+
+
+
 
 == Tasks