The motivation of a network creation
It is known that an operating system multi-tasking is more than one performance
single-tasking, that because of efficiency that it gives the first
compared to the last. This analogy is perfectly valid and
the retelisticsi. Thus, as the Internet (global network or
WAN - Wide Area Network) gained more ground in the last 10 years,
the quantity of information that circulates in this world has doubled or even
tripled.

The main advantage of using the information in a network is the possibility of
could be further forwarded to other customers / users.
This option gives the user the advantage of the network share
own resources (physical / logical) with other third parties from the network.
Why do you need to build a network
This tutorial describes logical configuration at a local LAN networks
(Local Area Network) and covers aspects of the design
Network (topologies, design rules, etc.).
Requirements physical (hardware)
- a network card (bus ISA / PCI) compatible with RJ45 Connectors
and / or BNC
- a computing system as performing cat
- a hub or switch to the interconnection of several clients Network
- cable (s) compatible network (s) UTP / STP respectively BNC (coaxial)
For the Virtual BNC connector (Bayonet Connector), respectively
coaxial cable you need terminatori in “T” to be attached
cable connected to the network card.
Requirements logical (software)
- operating system multi-tasking (ie Unix / Windows)
- protocols relating to the type of communication

CAUTION:
1.in not be repair threads but provided at both ends
Connectors with corresponding correctly;
2.don’t switch the cables between them (in case there are more) but to catch
adeziv band or insulated wire
3.nu to suspend cables unless their weight is not to overreact
sea;
4.keep the cables in the right angle but greater than or equal to 45 degrees

To connect two network interfaces directly uses cable type
“Crossover”, otherwise use cable “rollover”. In case
which will not comply with these rules, the connection will not work.
Network Configuration
After the installation of physical network equipment (network cards, cables,
hubs and switches) is moving to the logic of network configuration (insalarea
the necessary protocols, setting each iIP network
Gateway’s determination to present computer and the server
DNS - if it is present)
Setting IP interface for network (LAN card)
Each station / computer network will be identified by a unique address
32biti type Internet Protocol (IP). There will be accepted by the computer addresses
IP identical because they will generate conflicts in the network.
The IP address
IP address is one of many 32biti on 4 bytes, each being separated by byte
“.” This format is called May and the format of the decimal point with the IP address and
look like this:
XXX.XXX.XXX.XXX-x is a number in decimal format from 0 to 254
Thus, groups xxx each by 1 byte (1 byte = 8 bits; 8bits x 4
bytes = 32bits). Each set of 4 byte identify network or customer network
depending on the format address met by the network protocol (IP).

Classes network and network address format
Depending on the destination computer network will establish a class of addresses
IP for it.
A class addresses is a way segmentation physics / assignment of a
a customer network that certain classes of networks.
There are 3 classes of common network. In principle, but classes are the last 5
are used for government / military and are not encountered in
Internet.
First class network is type A.
The second class of network-type B.
A third class of network-type C.
Computers receiving IP addresses are either class A or B in either of the C
depending on the destination computer on which it occupies in the network.
format of Class
Class A includes the field and is 0-126 type:
RRR.CCC.CCC.CCC (R = network / C = client)
Field network (first octet of the IP address) indicates being a class A to class
up to 127 network (virtual reality in just 126 because 127 is used in
another purpose). The remaining fields indicating IPs for stations in the network
indicated in the first byte.
Example: 119.abc.def.ghi - this indicates a Class A (134 located in
domentiul 0-126, abc, def ghi being that the IP addresses of the clients of
119 network.
The Class B
Class B comprises the field and is 128-191 type:
RRR.RRR.CCC.CCC (R = network / C = client)
Fields network (first two bytes) indicates being a class B with a maximum
63 networks. The remaining fields indicating IPs for stations in the network
indicated in the first two bytes.

CAUTION:
The networks (ie 63 networks) Stones number of networks, not the number
clients of the network
Example: 171.27.abc.def - as the first octet fit in
128-191, this address is part of the class B addresses
Format C Class
Class C includes the field and is 192-223 type:
RRR.RRR.RRR.CCC (R = network / C = client)
The first 3 bytes of class format indicate a huge network, with 3 of 4 bytes
allocate network, only 1 byte being allocated to clients.
Example: 213.140.10.abc - the network is identified through the first 3 bytes,
‘abc”being reserved for the last byte of network clients.
Class C includes the fewer customers, as opposed to Class B or Class A, which is
with the most customers.
IP addresses are assigned by INTERNIC, provider classes IPs
or local ISP. These addresses are static counter-offered price and are
reserved for them at buy.
The price of IP addresses varies depending on its availability or
Depending on the class which is part of.
Thus, the IP addresses of Class A are used most often by mariile
corporations, the class B by corporate media and the class C
or small corporate users.
IP addresses reserved
There is but reserved addresses that can not be used as asigns AZ
or customers but are used for the purpose of managing the network.
Examples of such addresses is the address broadcast and the
loopback.
Broadcast address is used to send packages in a given
network segment or even in the whole network.
Loopback address is used as network identifier or address
International (often present for compatibility between operating system and
IP interface asignata of networki).
The locations are broadcast type type 000,000,000,000 or 255,255,255,255.
Example: 128.169.15.255 - indicate the transmission of broadcast to all stations
the network 128.169.15 (all stations of the network will receive packages sent to
broadcast address). Address type loopback can be 127, 192 or 0 (in the first
octet of the IP address)
In this case, loopback address is 0 for Class A, Class B for 127 and
192 for Class C.

Addresses loopback type can not be assigned only local (LAN), and can not be
assigned stations connected in the WAN.
Broadcast addresses can not be assigned at all because they are used in
for administration of the network.
What if we check card installed?
To do this, go to the menu “Start” -> “Settings” -> “Control Panel”
then go to the icon with the name “System” and click on the tab
“Hardware” - now press the button “Device Manager”.
in the “Network adapters” lies
installed a network card “Realtek RTL8139.
In the event that will be an exclamation point in the right name plaque will
have to install the appropriate drivers or to solve any
conflicts system.
In case appears symbol “!” It causes network adapter
severe problems operating system, for which reason the card is
disabled.
Another way to see if the card was installed successfully use
utility “ipconfig” Command Prompt such as: “ipconfig / all”.
The result of the order will be similar to the one below:

This can and if the cable is plugged in
correspondingly, if the routing is activated or if the proxy is WINS
used.
In addition, it will be offered and the MAC’s network.
Setting the IP network interface for
After the network card installed, you can install the drivers related move
setting up the IP for this interface. Thus, your computer will be
identified by the IP address. When the computer is located in May
many network interfaces, the computer will be asignata IP address
corresponds to the first interface. This is specified in the application of
configuration of the network as follows.
Access menu “Start” -> “Settings” -> “Control Panel”
In this window, go under the icon that says “Network and Dial -
Up Connections. ”

Execute left-click the connection icon and go to the menu
“Propreties.”
The next window left click on “Internet Protocol (TCP / IP) and
go to the “Properties” as follows:

By default, Windows operating system is set to auto-configure and IP address. November
we set manually because it is more effective and easier to manage that
we know the address asignet adapter.
So, check the option “Use the following IP address.”
Now you can specify the desired address.
Previous sections that explain the format of an IP address and
laying down rules.
Fields that can be edited containing IP’s network so that a
established, the network of which it forms part (in section “Subnet mask).
Optional, if you use a dedicated computer with access to services
Internet address specify in the field “Gateway“.
The image below shows a sample configuration of IP,
network and a Gateway.

Settings made above are valid for a computer that has access to
Internet Gateway’s “192.168.0.10″. In addition it will be specified and
server’s DNS to resolve Internet addresses (eg those introduced in
browser). Normally, the server’s DNS has the same IP address as a
Gateway’s computer because that is depending on the server and DNS.
You can also enter multiple addresses DNS. They will be
taken in order, from the top down. (if the first is not available or can not
resolve the request of the then second, if not third, etc.).
Settings described so far are valid for a computer that has access to
Internet service of a DNS server.
In case you have an Internet connection leave fields “Gateway”
and the “Use the following DNS server addresses” nil.
If there other computers to be connected to the network will
set IP addresses of the same class used for computer network
current.

For example, the following computer network will address
“192.168.0.2″, the third computer “192.168.0.3″, etc. up to a limit of 223
imposed Class C.
Testing operation of the network interface
To ensure that you have properly configured network card and have established
IP address, to test the connection using the “ping” under the “Command
Prompt “as” ping IP, where IP address is set for interface
this network computer.
ATTENTION: Under Windows 2000/XP is required to connect and put in
operation of computers connected together, otherwise the “ping” will
indicate a network nefunctionala. Example follows below:
The error message displayed by the “ping” unable to indicate
access specified address. This is due to be because of the
address is not in the network computer was the source (at that
access) - routing services are not put in operation or the server’s
DNS specified runs - enter an address or additional DNS
Gateway is not specified functions or restricted access to
routing services.
You can use the services routing of Windows or accessing services
routing of the Gateway.

We recommend to use the services routing of Windows-only event
in which the computer will be used as a server (for other Gateway
computers from the network).
To be sure that the problem comes from the cable is not connected
or computers that are not put into operation command call
“Ipconfig” and review the outcome

This will be displayed behind the command “ping IP, where IP is the IP address
computer to be tested.
The connection correct / physical cable between the computer
Computer date is the “ipconfig” as follows:
Sharing files in the network
Settings made up to now ensure the identification of computer
Currently the network. In order to enable file sharing network
May need a few steps.
It will also explain how the firewall is used in the present
Windows 2000.
Network Protocols
The Protocol represents a set of rules which two or more
computers need to know to communicate with each other.
Protocol what you used so far was “TCP / IP.” It is installed
by default in Windows 2000 installation and is used in
environment where this is necessary services based on this protocol.
Examples of such services would be services mail (SMTP, POP3), services
the browsing (HTTP) services, transfer files (FTP, TFTP) or any other type
services that are based on data transfer network.

This can deduce from the name and acronym “TCP / IP” - “Transfer
Control Protocol / Internet Protocol. ”
To transfer data in the local network (LAN) as the operating system
Windows is necessary to install a dedicated protocol and owner
Microsoft Corp.. called “NWLink” compatible or IPX / SPX.
The default Windows does not come installed with this protocol. To install it
go this way:
Access menu “Start” -> “Settings” -> “Control Panel” and execute doubleclick
icon “Network and Dial-Up Connections.” Click the left
icon on the network and execute option “Propreties.” In this window
click the “Install …” and click on the icon “Protocol” as
is displayed:
Now click the “Add …” and select the protocol “NWLink”

Just click on the “Okay” to complete the installation process.
In case you are asked to restart the system do this now.
After all stages described, continue with determination
resources you will share the network. These resources can be files, directories
with subdirectories, storage units, output units (printer, plotter,
fax).
Open the first window, Windows Explorer and click on the left
resource you want it a partajati. In the picture below is how
Director share of “My Documents”

Access now tab “Sharing” to reach the share options
displayed in the picture above.
Check option “Share this folder” to share directory. Optional,
established a name for the shared directory. This name will be displayed
computer that accesses it. In case you do not set any other name, will
use its original name.
After establishing the name click on the button “Apply” and “OK” after that
have to wait as the operating system has been set for access rights
shared resources.
Optional but recommended is to set access rights defined in
Depending on your preferences or environment in which to share resources or
categories of persons who are authorized to access resources.
By accessing understand reading, changing / writing, execution and
displaying content resources.
To set access rules click on the “Permissions”.

In the case of
front “Everyone” meaning that everyone has the rights checked in the section
“Permissions” - in the example above, anyone can have full control
on shared resources. (amending / read).
Depending on your needs, check the option to a comfortable feel that will better
environment in which resources will be shared.
It also can define certain categories / groups of people who will
rights files.
To add to the list of groups or individuals click on the button “Add” in
the “Share permissions.”

Select category / name of the person or group which give the right-giving
Double-click on it and click the “OK”. If the girl has been chosen
“Authenticated Users” - users login - this group is
users accessing your resources by a password.

You can see that this category is assigned only the right read on
resources. These include displaying only the content of resources.
In addition to May set the limit what users can access resources
your This can set a window of establishing shared resources
under the “User Limit” and “Allow … users “.
Configuring the Firewall
By default, after the network configuration, the system’s firewall is not enabled
which can be dangerous in case your information are a big
important and could be corrupt, or viewed by some
Why do not people should have these rights.

Persons who brock networks and destroy / altereaza information from a
CRACKERs system are called. Persons who broke networks and
visualize / copies of the information system of calculation is called penetrated
HACKERS, the difference between the two types of people is that the
Following the ethics and not destructive.
To activate the firewall go to “Start” -> “Settings” -> “Control
Panel “->” Network and Dial-up Connections “and click on the right
Network icon and then click the option “Properties”.
Select Protocol “TCP / IP” and click the “Properties” then
click the “Advanced” window of what will be displayed. Now call tab
“Options” and select TCP / IP filtering “as follows:

Check the box “Enable TCP / IP Filtering” as the image appears in May
above rules specify that after each item in this window.
These rules apply to ports TCP / UDP and the protocols.
To block such as port 22 (this corresponds to port SSH’s)
select “Allow Only” and add the port hit 22 after which “Okay”