Network Administrator:
A member of a staff or group of a staff who have the responsibility for the smooth functioning of a large network. They carry out a number of functions: defining and enforcing security policies, specifying routing policies, accounting for system resources on the network and ensuring that they are efficiently used, responding to hardware and systems errors, and administering any connections to external networks such as the Internet. Sometimes the termSystem Administrator is used to describe a network administrator although this may be someone who administers a small network where many of the network functions tend to be trivial.
Skills needed to become a systems administrator:
The subject matter of systems administration includes computer systems and the ways people use them in an organization. This entails knowledge of operating systems and applications, as well as hardware and software troubleshooting, but also knowledge of the purposes for which people in the organization use the computers.
However, perhaps the most important skill to a system administrator is problem solving frequently under various sorts of constraints and stress. The sysadmin is on call when a computer system goes down or malfunctions, and must be able to quickly and correctly diagnose what is wrong and how best to fix it.
System administrators are not software engineers or developers. It is not usually within their duties to design or write new applications software. However, sysadmins must understand the behavior of software in order to deploy it and to troubleshoot problems, and generally know several programming languages used