a+ network+ security+

 The computer

Most of the components of a medium network are individual computers, also called hosts; they are generally workstations or servers .

Cards of red

To achieve the link between computers and transmission media ( network cables or physical media for wired and infrared networks or radio frequencies for wireless networks ), it is necessary to intervene a network card or NIC (Network Card Interface) with which data packets can be sent and received from and to other computers, using a protocol for their communication and converting this data to a format that can be transmitted by the medium (bits 0's / 1's). It should be noted that each network card is assigned a unique identifier by its manufacturer, known as MAC (Media Access Control) address, which consists of 48Bits (6 Bytes ). Said identifier allows directing the data traffic of the network from the sender to the appropriate receiver.

The job of the network adapter is to convert the electrical signals that travel through the cable (eg: Ethernet Network ) or radio waves (eg: Wifi Network ) into a signal that the computer can interpret.

These adapters are PCI cards that plug into expansion slots on your computer. In the case of notebook computers, these cards come in PCMCIA format . In some modern computers, both desktop and laptop, these cards are already built into the motherboard.

Network adapter is the generic name given to the devices in charge of carrying out this conversion. This means that these adapters can be both Ethernet and Wireless , as well as other types such as fiber optic , Coaxial , etc. Also the available speeds vary according to the type of adapter; These can be 10, 100 or 1000 Mbps in Ethernet, and 11 or 55 Mbps in wireless.

Types of work sites

There are many types of workstations that can be incorporated into a particular network, something which has exhibits high-end systems with multiple CPUs , large amounts of RAM , large amounts of storage space on hard disk , or other components required for special data processing tasks, graphics, or other resource intensive applications. (See also the network computer).

Types of servers

In the following lists there are some common types of servers and their purposes.

File Server - Stores various types of files and distributes them to other clients on the network.

Print Server - controls one or more printers and accepts print jobs from other clients on the network, queuing print jobs (although you can also change the priority of different prints), and performing most or all other functions that on a job site it would be done to accomplish a printing task if the printer were directly connected to the printer port of the job site.

Mail Server - Stores, sends, receives, routes, and performs other email- related operations for clients on the network.

Fax Server : Stores, sends, receives, routes and performs other functions necessary for the proper transmission, reception and distribution of Faxes .

Telephony server : performs functions related to telephony, such as an answering machine , performing the functions of an interactive system for voice response, storing voice messages, routing calls and also controlling the network or the Internet ; p. Eg, excessive voice IP ( VoIP ) gateway .

Proxy server : performs certain kinds of functions on behalf of other clients on the network to increase the performance of certain operations (eg, prefetching and depositing documents or other data that are requested very frequently). It also serves security; that is, it has a Firewall (firewall). Allows you to manage internet access on a computer network by allowing or denying access to different websites.

Remote Access Server (RAS) : controls the Modem lines of the monitors or other communication channels of the network so that requests connect to the network from a remote location, answer incoming telephone calls or recognize the request from the network and perform the necessary security checks and other procedures necessary to register a user on the network.

Usage Server : Performs the Logical part of the computing or business of a client use, accepting instructions for operations to be performed from a job site and serving the results in turn to the job site, while the site Worker performs the Operator Interface or the GUI portion of the process (that is, the presentation logic) that is required to work properly.

Web server : stores HTML documents , images, text files , scripts, and other web material composed of data (collectively known as content), and distributes this content to customers who request it on the network.

Backup Server - You have the Network Backup Software installed and have large amounts of network storage on hard drives or other forms of storage (tape) available for use to ensure that the loss of a server main does not affect the network. This technique is also called clustering .

Printers : many printers are capable of acting as part of a computer network without any other device, such as a "print server" , to act as an intermediary between the printer and the device that is requesting a print job to be finished a+ network+ security+.

Terminal : many networks use this type of equipment instead of workstations for data entry. These data are only displayed or entered. This type of terminal works against a server, which is the one who actually processes the data and sends data screens to the terminals.

Other devices : there are many other types of devices that can be used to build a network, many of which require an understanding of more advanced computer networking concepts before they can be easily understood (eg, cubes, routers, bridges, switches, hardware firewalls ). In home and mobile networks, connecting consumer electronics to devices such as video game consoles is becoming more and more common.

Authentication server : It is in charge of verifying that a user can connect to the network at any access point, whether wireless or cable, based on the 802.1x standard and can be a RADIUS-type server.

DNS server : This type of servers resolve domain names without having to know their IP address.