LAN (Local Area Network)

Senin, 16 Mei 2011

Setting Local Computer Networks (LAN - Local Area Network) using Windows XP

Setting Local Computer Networks (LAN - Local Area Network) using Windows XP

The procedure is performed to configure the Network Adapter Card (can be seen in the picture as above).

1. Click Start à Settings à Control Panel to exit the Control Panel dialog box (as seen drawn below)

2. Double-Click Network Connection Icon to exit the Network Connection dialog box

3. Double-click Local Area Connection icon to exit the dialog box Local Area Connection Status

4. Click the Properties dialog box to exit Local Area Connection Properties

5. Double-Click Internet Protocol (TCP / IP) that is in the Local Area Connection dialog box to exit the Properties dialog box only: Internet Protocol (TCP / IP) Protocol

Enter the IP address data as shown above. Data IP Address every UAD will be different and unique (not the same between one AUD UAD Campus Campus III with another). Data IP Address is, will be given when Broadband installation is complete (when the network activation)

IP Address data most needed by every PC that will be set on each remote UAD is as follows:

1. Default Gateway IP Address from the modem à Broadband. Given the time following the activation.

2. IP Address IP Address à This is one class with Broadband Modem IP (IP Default Gateway) later.

3. Subnet Mask à Data Block IP that will be given, must her ingclude the Subnet Mask of this data.

4. After the data the TCP / IP is entered, click OK to close the dialog box Internet Connection (TCP / IP) Properties

5. click OK to close the dialog box "Local Area Connection Properties"

6. Click Star à Run à to exit the RUN dialog box, then type CMD to get out a new dialog box "command"

7. In the dialog box "Command" earlier, type: ipconfig

If the Ethernet from the computer is not connected to the LAN, will come out the result as shown below.

7.1. If the PING test performed when the condition has not been connected to the LAN computers, will get the results as shown below.

7.2. After the computer is connected to the LAN, type IPCONFIG / ALL to see the IP address attached to the computer user. The result can be seen as shown below.

If the ping test results obtained (Request timed out), probably no problem on local network.

Possible problems can exist from the following:

- Connector cable network (LAN cable) installed less taut. Fasten à LAN cabling connections to the port Ethernet Hub and LAN PC Card

- LAN cable is not good (there are pin-pin connection cable that broke in the middle) Replace with a good cable to another LAN

- Port Ethernet Hub which is not good (or bad loose contact) à Try moving the port

If the ping test results obtained as the image above (Reply from xxxx), we can be sure that the network operates normally.

Each user on a remote network UAD, expected at least, can perform an action as above. The target users in the UAD is making sure the local network to connect with IP Ethernet LAN of Broadband Modem which is a network gateway to the Network Server UAD UAD center and the Internet.

If PC users have been able to do the ping test as above, and get results Reply from xxxx à (Ip modem), then certainly in the UAD LAN network is no problem.

After ensuring the LAN network is not a problem, users in the UAD directed to perform TEST PING IP Address Server Central. How to ping test is similar to an IP ping test modem in a local network. The difference is only in the IP ADDRESS which will be included in the ping IP address existing computers at headquarters, or IP Address on the Internet. Next dilakuka test applications - Internet applications.

Setting and Clas TCP / IP

Setting and Clas TCP / IP

TCP / IP protocol

Because an important role in the Windows operating system and also because the protocol TCP / IP is the protocol options (default) from Windows. TCP protocol is in the Transport layer of the OSI model (Open Systems Interconnection), while the IP is at the Network layer of the OSI mode

IP Address

IP address is the address given on computer networks and network equipment that uses TCP / IP. IP addresses consist of 32-bit binary numbers that can be written as four decimal numbers separated by dots such as 192.168.0.1.

Network ID Host ID

IP addresses consist of two parts: network ID and host ID, which the network ID to determine the network address of the computer, while the host ID to determine the host address (computers, routers, switches). Therefore the IP address provides the full address of the host and network address where the host is located.

IP Address Classes

Class Network ID Host ID Default Subnet Mask

A xxx.0.0.1 s / d xxx.255.255.254 - defaul subnet mask: 255.0.0.0

B xxx.xxx.0.1 s / d xxx.xxx.255.254 - defaul subnet mask: 255.255.0.0

C xxx.xxx.xxx.1 s / d xxx.xxx.xxx.254 - defaul subnet mask: 255.255.255.0

IP addresses are given for the class A network with a very large number of hosts. IP Range 1.xxx.xxx.xxx. - 126.xxx.xxx.xxx, there were 16,777,214 (16 million), an IP address in each class A. IP addresses are given for the class A network with a very large number of hosts. In class A IP address, network ID is the 8 bit first, while the host ID is 24 bits next.

Thus, how to read the IP address class A, for example 113.46.5.6 is:

Network ID = 113

Host ID = 46.5.6

So the above means the host IP address on network 46.5.6 number number 113.

Class B IP address is usually allocated for medium and large sized networks. In class B IP address, network ID is 16 bits first, while the host ID is 16 bits next.

Thus, how to read a class B IP address, for example 132.92.121.1

Network ID = 132.92

Host ID = 121.1

So the IP address above means the host number 121.1 on the network number 132.92. with host ID 16 bits long, the network with the IP address class B can accommodate about 65,000 hosts. IP Range 128.0.xxx.xxx - 191.255.xxx.xxx

Class C IP address originally used for small networks (LAN). Host ID is 8 bits last. With this configuration, can be formed about 2 million networks with each network has 256 IP addresses. IP Range 192.0.0.xxx - 223.255.255.x.

The allocation of IP address is basically the process of selecting the network id and host ID is right for a network. Whether or not this exact configuration depends on the objectives to be achieved, namely to allocate IP addresses as efficiently as possible.

Domain Name System (DNS)

Domain Name System (DNS) is a system that allows the name of a host on a computer network or the Internet are translated into IP addresses. In giving the name, the DNS uses a hierarchy architecture.

1. Root-level domains: is the top level is displayed as a dot (.).

2. Top level domains: code category or state organizations such as:. Com for use by the company;. Edu for use by the college;. Gov for use by government agencies. In addition, to distinguish the use of name by a country with other countries to use such marks. Id to Indonesia or. Au for Australia.

3. Second level domain: the name for the organization or company, for example: microsoft.com, yahoo.com, etc..

DHCP (Dynamic Host Configuration Protocol)

IP address and subnet mask can be provided automatically using Dynamic Host

Configuration Protocol, or entered manually. DHCP function to provide IP addresses automatically on computers that use TCP / IP protocols. DHCP works with the client-server relationship, where the DHCP server provides a group of IP addresses that can be given to the DHCP client. In providing this IP address, DHCP IP address only lend it. So giving the IP address takes place dynamically.

Network Topology is the physical description of the pattern of relationships between network components, including servers, workstations, hubs and pengkabelannnya. There are three kinds of commonly used network topology, the Bus, Star and Ring.

This type of computer network cabling

This type of computer network cabling

There are several types of wiring used and can be used to apply the Network, namely:

Thin Ethernet (thinnet)

Thin Ethernet or thinnet have advantages in terms of the relatively cheaper cost compared to other types of cabling and the installation of components easier. The length of thin wire coaxial/RG-58 between 0.5 - 185 m and a maximum of 30 computers connected.

Thick Ethernet (Thicknet)

With a thick Ethernet or thicknet, the number of computers that can be connected in a network will be more and the distance between the computers can be enlarged, but the cost of procurement is more expensive wiring and installation is relatively more difficult compared with thinnet. In Thicknet transceiver used to connect each computer to the network system and connectors used are type DIX connector. Maximum transceiver cable length 50 m, Thick Ethernet cable maximum length 500 m with a maximum 100 transceiver connected.

Twisted Pair Ethernet

Twisted Pair cable is divided into two types of shielded and unshielded. Shielded cable is the type that has a sheath wrapping while unshielded not have a sheath wrapping. For this type of connection cable uses an RJ-11 or RJ-45. In twisted pair (10 BaseT) network, a computer arranged to form a star pattern. Each PC has one twisted pair cables are centralized at the HUB. Twisted pair is generally more reliable (reliable) than thin coax because the HUB has the capability of data error correction and increase the speed of transmission.

Currently there are several grades, or categories of twisted pair cable. Category 5 is the most reliable and have high compatibility, and the most recommended. Running well at 10Mbps and Fast Ethernet (100Mbps). Category 5 cable can be made straight-through or crossed.

Straight through cable used to connect computers to the HUB. Crossed cable used to connect the HUB to HUB and Broadband Modem directly to a PC (without HUB). Maximum cable length Twisted-Pair cable is 100 m.

Fiber Optic

Network that uses fiber optic (FOR) are usually large companies, due to price and installation process more difficult. However, networks that use the FOR in terms of reliability and speed is not in doubt. Data transmission speeds by more than 100Mbps FO media and free environmental influences.

Getting to know the LAN

Getting to know the LAN

TCP / IP (Transmission Control Protocol / Internet Protocol) is a group of protocols that manage computer data communications on the Internet. The computers that connect to the internet to communicate with TCP / IP, because it uses the same language differences in types of computers and operating systems is not a problem. Computer PC with Windows operating systems can communicate with Macintosh computers or with a Sun SPARC running Solaris. So, if a computer using TCP / IP and is connected directly to the internet, then the computer can be connected with computer anywhere in the world that also connect to the internet
The characteristics of computer networks:

1. share hardware (hardware).

2. sharing software (software).

3. sharing of communication channels (internet).

4. sharing data with ease.

5. facilitate communication between network users.

Local Area Network (LAN) is the number of computers linked together in one particular area that is not so broad, as in one office or building. Broadly speaking there are two types of network or LAN, the network Peer to Peer and Client-Server networks.

In peer to peer network, every computer connected to the network can act both as workstations and servers. While on the network Client-Server, only one computer that acts as a server and other computers acting as workstations. Between these two types of networks each have advantages and disadvantages, in which each will be explained.

LAN is composed of several basic elements that include hardware and software components, namely:
Physical Component

Personal Computer (PC), Network Interface Card (NIC), cable, network topology

Component Software

Network Operating Systems, Network Adapter Drivers, Network Protocols.

Personal Computer (PC)

Type used in personal computers in the network will greatly determine the performance of the network. Computers with high performance will be able to send and access data in the network quickly. In the Client-Server type networks, computer servers that functioned as an absolute must have higher performance than other computer as his workstation, because the server will be responsible for providing facilities and managing the network operations.

Network Interface Card (NIC)

Based on the type of bus, there are several types of network interface card (nic) or network card, the ISA and PCI.

We have kind of network cards that are widely used, namely PCI

Senin, 25 April 2011

Setting up the Server

Setting up the Server

For starters, lets configure the /etc/dhcpd.conf file. It's pretty self explanitory. If you are planning on setting up a local DNS server leave in the 3 lines pertaining to Dynamic DNS, otherwise take them out.

#
# Global Settings
#

# Turn on Dynamic DNS:
ddns-domainname "domain.lan";
ddns-update-style interim;
ddns-updates on;

# Don't allow clients to update DNS, make the server do it
# based on the hostname passed by the DHCP client:
deny client-updates;
allow unknown-clients;

#
# 10.0.0.0/255.255.255.0 Scope Settings
#
subnet 10.0.0.0 netmask 255.255.255.0 {

# Range of DHCP assigned addresses for this scope
range 10.0.0.100 10.0.0.200;
# 1 day
default-lease-time 86400;
# 2 days
max-lease-time 172800;

# Configure the client's default Gateway:
option subnet-mask 255.255.255.0;
option broadcast-address 10.0.0.255;
option routers 10.0.0.2;

# Configure the client's DNS settings:
option domain-name "domain.lan";
option domain-name-servers 10.0.0.1;

}

Now things get a little tricky. If you have Windows clients you are going to need to modify the /etc/rc.d/init.d/dhcpd file. In the start() directive you should see a line that looks something like

daemon /usr/sbin/dhcpd ${DHCPDARGS}

Comment that out with a # and add in the following lines. If you want, add in the DHCPDARGS also, but I don't really use it.

/sbin/route add -host 255.255.255.255 dev eth0 2> /dev/null
daemon /usr/sbin/dhcpd eth0

Make sure you set the ethx to the network interface you want to serve dhcpd requests on. This is particularly vital if you have a multihomed server.

Setting up the Client

The client needs to send a hostname for this to work correctly. The DHCP server needs to know what hostname to set in DNS. Windows does it by default, however you'll need to make sure your /etc/sysconfig/network-scripts/ifcfg-ethx file looks something like this (with the DHCP_HOSTNAME directive set properly.

# make sure this line is has no settings on it!
DEVICE=eth0
BOOTPROTO=dhcp
HWADDR=01:01:01:01:01:01
ONBOOT=yes
TYPE=Ethernet
DHCP_HOSTNAME=host
USERCTL=no
PEERDNS=yes

Rabu, 06 April 2011

Virtual Private Network

Virtual Private Network
Is to create networks in the network for various data sharing, internet, remote, and others, the goal that can not be in hacker by hackers because is hidden within the network itself, so to get into where we have to get past first base and the main network new search for each one of all the existing network so that so hard for the broken-down by hackers

Virtual Private Network configuration can be in accordance with what we want and it's up to anything like the made for various kinds of files, email, internet etc.

Tools to create a VPN network:
Modem
Router
Servers
Proxy
Client computer 2 groups
Cable Network, Wireless
To Start making VPN network we need to select the IP address (Internet Protocol) on a network, Local Area Network (LAN) which will be made in the IP address to be VPN. Can connections work flawlessly usually we input the ip address that will go with the first configuration if it is in the configuration we need to test with the use of ping, try pinging the IP address we have on the configuration of whether to connect or not. if it can ping it straight toward the goal has stayed us how to configure various types of files, emails, internet for sharing.

With the VPN security will be more secure and safe enough not afraid of a hacker to your network, use a VPN if you have 2 pieces of plant or a different office location for the network safer and more controlled.

Tunneling protocols can be used in a point-to-point topology that would theoretically not be considered a VPN, because a VPN by definition is expected to support arbitrary and changing sets of network nodes. But since most router implementations support a software-defined tunnel interface, customer-provisioned VPNs often are simply defined tunnels running conventional routing protocols.

On the other hand provider-provided VPNs (PPVPNs) need to support coexisting multiple VPNs, hidden from one another, but operated by the same service provider.

Firewall is a term commonly used to refer to a component

Firewall is a term commonly used to refer to a component or a set of network components, which serve to restrict access between two networks, more specifically, between the internal network with a global network Internet. Firewalls have several tasks: First and foremost is: must be able to implement security policies in the network (site security policy). If certain actions are not permitted by this policy, the firewall must be assured that all the effort that represents the operation should fail or be defeated. Thus, all the illegal access between networks (not authorized) will be rejected. Perform filtering: require all existing traffic to pass through the firewall for all the process of granting and utilization of information services. In this context, the flow of data packets from / to the firewall, have been selected based on the IP-address, port number, or direction, and adapted to the security policy. Firewalls also need to record / record suspicious events and notify administrators of all the efforts through security policy. Planning Network Planning With Firewall firewall system on the network, is closely related to what kind of facilities will be provided for the users, the extent of the risk-level security that can be accepted, and how much time, money and expertise are available (technical and economic factors). Firewalls are generally composed of the filter (also called a screen or a choke) and the gateway (gate). Filter function to restrict access, narrowing the channel, or to block certain traffic classes. The occurrence of access restrictions, will reduce the function of the network. To keep the network communication function in an environment that had a firewall, generally taken two ways: First, if we imagine the network we are in a fortress of protection, communication can occur through the exit doors of the fortress. This method is known as packet-filtering, which filters only be used to deny traffic on an unused channel or canal with pretty big-security risks, while traffic on other channels are still allowed. The second method, using the proxy system, where every communication that occurs between the two networks must be made through an operator, in this case the proxy server. Some protocols, such as telnet and SMTP (Simple Mail Transport Protocol), will be more effectively dealt with the evaluation packet (packet filtering), while others such as FTP (File Transport Protocol), Archie, Gopher and HTTP (Hyper-Text Transport Protocol) will more effectively handled by a proxy system. Most firewalls use a combination of these techniques (packet filtering and proxies).

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