Network Services

Network services are crucial for a networked computer environment as they provide the basic foundation on which they are built. In a common network, resources are shared amongst a group of individual computers; this is accomplished by installing general network services over one or more servers.

In order for these network services to maintain a secure and user friendly operation, they must be configured on a corporate Local Area Network, or LAN. These corporate LANs make sure that everyone in the network has a valid IP address using DHCP. Other network services may also be used, like the Domain Name System which assigns easy to remember names to each IP address, for example.

Common network services include, but are not limited to, authentication servers, directory services, DHCP (Dynamic Host Configuration Protocol), DNS, email, printing, and network file system.

Authentication Servers

Authentication servers, as the name suggests, provide services which authenticate services to users or other systems by networking. Cryptographic tickets are assigned to remotely placed users in order to authenticate said server. This authentication is important as it provides the basis for 3 major functions:

- Authorization - to determine whether or not certain users or processes will be granted a privilege.
- Privacy - to keep certain information from being known to non-participating parties.
- Non-repudiation - which is not being able to deny something that was done as long as it has been authorized to be done by the authentication.

In brief, an Authentication server stores user names and passwords so that it may identify the clients as they log in. In addition, it may hold algorithms used for taken access. Sometimes the server may also store user permissions and certain company policies or even provide access to directories which contain this information.

Directory Services

In order to understand what directory services are, it is first important that you know what a directory is. A basic definition of a directory is almost like a dictionary as it allows the user to look up a name and any information that is associated with it. Actually, it is not unusual for there to be many different sets of information allocated to a particular name. Put simply, a directory service is a software program that stores, organizes, and provides access to information in these directories.

When it comes to these directories, they may be very narrow in scope, containing only a small set of node and data types, very broad supporting even arbitrary or extensible types, or anywhere in between the two. Nodes, in a DNS, are the data items and IP addresses; in a network operating system directory these nodes are resources manages by the operating system such as users, printers, computers, and any other shared resources.

One of the simplest types of directory services is the naming service; its function is to map the names of the network resources to their respective network addresses. When using this type of directory, it is not necessary for the user to remember the physical address of a particular network resource. In order to locate the resource, the user need only to provide the name.

Ultimately, directory services are nothing more than shared information infrastructures which serve to locate, manage, administer, and organize related items and contact resources which will often times include volumes, folders, printers, files, users, devices, groups, and telephone numbers, as well as other objects. These directory services are an important part of a Network Operating System. In larger cases, they will also serve as central information repositories for Service Delivery Platforms.

Dynamic Host Configuration Protocol

The DHCP as it is more commonly called is a type of network application protocol used by devices known as DHCP clients that are used in order to obtain configuration information for operation in an Internet Protocol network. Simply put, this protocol serves to reduce system administration work load. This lets devices be added to the network with little if any manual actions by the user.

The DHCP server overlooks a controls a large number of IP addresses and other important information about client configuration details. It depends on the specific implementation, but DHCP has 3 different ways that it may find certain IP addresses:

- Dynamic allocation - is a network administrator that assigns a wide range of IP addresses to DHCP.
- Automatic allocation - is when the DHCP server will permanently assign a free IP address to a client using a range defined by the administrator.
- Static allocation - is when the DHCP server assigns an IP addresses based on a table of MAC IP address bars.

Email

Email is a widely used method of communication where a person will use a personal computer, or other electronic device, in order to compose and send a message to another person. Most often they are sent via a computer connected to a network using modems or wireless transmissions.

Network File System

A network file system is used to share files, printers, and any other resources as persistent storage over a network of computers. These were first developed in the 1970s by the Digital Equipment Corporation. These systems were further improved upon in the 1980s, particularly by Sun Microsystems which created the File Access Listener, a file system what would eventually go on to become the most widely used file system based on Internet Protocol.

In order to measure the performance of a network file system, the length of time needed to satisfy service requests. In your average system this time frame will include the disk access time and usually a small amount of CPU processing time. A network file system however does require additional time to request a server and receive a response.

Conclusion

Network services, while largely out of use only a couple of decades ago, are now used by the majority of the population. As technology continues to progress, we can safely expect to see vast improvements on network services that will allow our use of them to be even more convenient and efficient in the future.

Network Services