Chapter Summary

Network security is a complex subject, and it should be a primary focus for any network administrator.

Being able to effectively secure a network involves understanding the risks that can be a threat to the network as well as what the result of a breach in security might entail.

There is a distinction between physical security and logical security. Physical security involves physically protecting data by controlling access to the network equipment or servers that hold that data. Logical security involves protecting the data on a network from being accessed by unauthorized personnel.

Network operating systems include features that allow you to protect the data on a network by providing authentication capabilities, logon restrictions, file system rights, and in some cases, auditing. Depending on the environment, you might not use all these features, but you are sure to use some of them.

Two important elements of a network security picture are the use of proxy servers and firewall systems. A firewall system acts as a protective layer to network access by controlling the traffic that passes between the interfaces on the system. Proxy servers allow you to centralize access to the Internet and therefore provide a way to control and monitor network access.

Understanding how implementing security features such as port blocking and encryption will affect the network and the users on it is another important aspect of network security.

As well as implementing measures that serve to protect the network, you must also be able to detect intrusions to the network and provide procedures that define what steps should be taken when a breach does occur. All these elements must be combined in order to have an effective network security policy.