Here Policies means, network security analyst write various security restriction codes to prevent users to visit certain web sites and do some content filter on the websites or by using various firewalls they write rules to prevent the users are known as Security policies.
How Network security different from computer security?
Securing network infrastructure is like securing possible entry points of attacks on a country by deploying appropriate defense. Computer security is more like providing means of self-defense to each individual citizen of the country. The former is better and practical to protect the civilians from getting exposed to the attacks. The preventive measures attempt to secure the access to individual computers--the network itself--thereby protecting the computers and other shared resources such as printers, network-attached storage(NAS) connected by the network. Attacks could be stopped at their entry points before they spread. As opposed to this, in computer security the measures taken are focused on securing individual computer hosts. A computer host whose security is compromised is likely to infect other hosts connected to a potentially unsecured network. A computer host's security is vulnerable to users with higher access privileges to those hosts.
NAS:
Network attached storage: You can build your own NAS device for your home.
Example: Convert you old machine to an NAS
Step 1: Use a old machine which is of no use nut make sure it runs with a minimum memory of 256 MB for a better performance and 10/100 Mbits Ethernet port on it and Use as much as space you need to save all your information ( i.e. your Hard drive size)
Step 2: Create a network either it can be a peer-peer or it can be LAN based on your needs. Share access to the Hdd on the NAS to access it from your LAN machine.
Step 3: Secure your NAS device now. Either you can use the basement of the building or a secured private location can also be preferred. Here comes the physical security to your device.
