Kamis, 01 Agustus 2013

DHCP Server

To administer a small network, providing a static ip very easy for network administrators. However, if the network has wide ranging possibilities for using the same ip will be large, causing conflict. On this basis, the use of DHCP (Dynamic Host Configuration Protocol) server is highly recommended.
The main function of this is to provide a DHCP server IP to the host or computer connected to the network automatically. This only applies if the computer is using IP settings with DHCP or in Windows to enable the option "Obtain IP Address Automatically". What if the computer still want to use a static IP? IP could thus not be given on the computer that will ask the DHCP Server IP or change the IP of a host that has been using the same IP with a static IP is used.
 If there is a DHCP server with the IP range 192.168.1.22 to 192.168.1.50 then any computer connected to the network and enable the use of DHCP, the DHCP server will assign IP addresses in the range above that is between 22-50, usually DHCP server assigns IP at the top of the range first. If in our example is a new one that uses DHCP then most likely get IP 192.168.1.50. If in the network there is a computer with Static IP and still within range of the IP DHCP Server DHCP Server will not use the IP to be given to any other DHCP users.
 What about Slackware 12.2 Linux itself? By default DHCP Server already installed on your Slackware machine, ie dhcp-3.0.6-i486-1.
smkn3tkj root @ server :/ # ls / var / log / packages / | grep dhcp
dhcp-3.0.6-i486-1
dhcpcd-2.0.8-i486-1
 You see that on the machines we have installed the package dhcp-3.0.6-i486-1. There is one file that we will edit as needed in building a DHCP Server, namely:
/ Etc / dhcpd.conf
If we look at the contents of the file with the command glittering cat / etc / dhcpd.conf
# Dhcpd.conf
#
# Configuration file for ISC dhcpd (see 'man dhcpd.conf')
#
dhcpd.conf file is still empty means now we will take dhcpd contained on / usr/doc/dhcp-3.0.6/examples/dhcpd.conf through ways:
smkn3tkj root @ server :/ # cp / usr/doc/dhcp-3.0.6/examples/dhcpd.conf / etc
now you have to edit the dhcpd.conf file in the directory / etc / dhcpd.conf
Penegditannya way like this:
smkn3tkj root @ server :/ # mcedit / etc / dhcpd.conf
Here's the parts you want to edit:
# Option definitions common to all supported networks ...
line: 1: option domain-name "example.org";
line: 2: option domain-name-servers ns1.example.org, ns2.example.org;
 The first two lines are setting the gateway, line 1 is the domain-search, specify the domain name you read back on the previous tutorial here for setting up DNS. While line 2 is namaservernya. Please feel free to edit as needed. This is an example of DHCP that have been made:
option domain-name "TKJ-smk3bgr.net";
option domain-name-servers 192.168.1.21;
 The second line should be filled with the IP address or a valid nameserver, or DHCP Client we can not access the public domain. Since in this example already exists in the DNS Server IP Address 192.168.1.21 then it will use.
We are also required to add the following line according to the rules of the Internet Systems Consortium. If you do not believe put a # to make comments and guaranteed dhcp server will not start.
ddns-update-style ad-hoc;
 Option to specify the time of the DHCP Server to IP administration and re-checking of Host is still active or not.
default-lease-time 600;
max-lease-time 7200;
Next is the determination of the range of IP addresses or subnets known as:
This example from dhcpd.conf default
# This is a very basic subnet declaration.
subnet 10.254.239.0 netmask 255.255.255.224 {
range 10.254.239.10 10.254.239.20;
option routers-rtr-1.example.org 239-0, 239-0-rtr-2.example.org;
}
edit as below:
# This is a very basic subnet declaration.
subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.22 192.168.1.50;
option routers 192.168.1.21;
}
 On the subnet configuration above, we make the DHCP Server on the network 192.168.1.0 with netmask 255.255.255.0 with DHCP IP range is 192.168.1.22 - up to 192.168.1.50 In this section there is also a significant option routers ip gateway from DHCP IP. Option routers can also be placed outside (Global) so by default will put option routers on the subnet unless explicitly stated.
Here is the complete config of dhpcd.conf that have been made:
option domain-name "TKJ-smk3bgr.net";
option domain-name-servers 192.168.1.21;
ddns-update-style ad-hoc;
default-lease-time 600;
max-lease-time 7200;
subnet 192.168.1.0 netmask 255.255.255.0 {
range 192.168.1.22 192.168.1.50;
option routers 192.168.1.21;
}
The next course dhpcd activate the server:
Command to enable dhcp on your Slackware system:
smkn3tkj root @ server :/ # / usr / sbin / dhcpd
This command to enable dhcp on reboot when system slackware.
echo "/ usr / sbin / dhpcd" >> / etc / rc.d / rc.local

READ MORE - DHCP Server
READ MORE - DHCP Server

A modem connects



A modem connects
A modem connects your computer to your Internet service provider or ISP. The connection is established through your phone lines. You must have seen a line taken from your phone going into the modem. It simply converts the signals coming from your phone into signals that can be understood by your computer. A router on the other hand assists the connection between computer networks. This device does not do any conversions. It 'routes' signals to a particular network or a computer in the network. Therefore it is called a router. Also read about how does a wireless router work.

Type of Connection
As the router and the modem are establishing a connection between different things, the type of connection they use is also different. The modem connects to the computer (through a router or directly) using a type of connection called RJ45. But it connects to the telephone line through a connection known as RJ11. RJ stands for 'Registered Jack' and its different types are used for different types of network interfaces. The Router on the other hand utilizes only the RJ45 type of connection. This is because it does not have to interact with telephone lines. It deals with computer signals only.

Function
The router vs modem differ in their functionality also. Rather that is the most important difference between them. A modem receives signals from a telephone line which carries analog signals. While delivering this signal to a computer, the modem converts the signal to digital signal. Because a computer can understand only digital signals. This process is known as modulation and demodulation of signals and thus it is called MoDem. Read what does modem stand for? These days cable modems have arrived which work differently. Read what is cable modem. They receive signals from the cables that deliver various channels to your computer. The basic working of the modem still remains same.

The function of a router is to just pass on signals coming from a modem to the right computer network or computer. That is, it just routes data so it is called a router. The router does not perform any conversions but it does filter the data while passing it on. Security measures like firewalls are implemented in the router. Though necessary, a router is not mandatory for establishing an Internet connection. Whereas, a modem is mandatory for an Internet connection. Although, a modem only converts and sends data, so it cannot be used to add security to your network or computer. Also, if you want to use wireless Internet, you have to use a router.

So this was the basic comparison of router vs modem. But you should note that this was only a broad overview and that the topic runs deeper still. There is another comparison, cable modem vs wireless router that talks about a little more details, and you can go through it for more information.
READ MORE - A modem connects
READ MORE - A modem connects

WEP key

The first and simplest thing you can do is check your wireless network connection and see if it is safe. When you install your router, you are given the option key setting wireless encryption protocol (WEP). Basically this is a password-protected method to log on to your own wireless network. If you do not have it, you operate an open network. That means anyone within range can use your wireless for free. While this is not hacking, but it is debatable whether this is actually a steal. In any case, if you do not have a WEP key, then you are vulnerable to illegal access of WiFi network connection.

 Even if you have a WEP key, it does not mean that your neighbors can not pass it. To determine whether someone is logged into your wireless network, you can do so by checking the logs your wireless network. To do so, click the Start Menu in Microsoft Windows, then double-click My Network Places. Next, double-click View Entire Network. If there are more devices connected than you have or allowed on your network, then it seems there is a WiFi thief.

 A similar method for determining the status of WiFi user list is to check your router's DHCP client table. Just as I view the network, the DHCP client table would list the machines on your network connection. If the number exceeds what you set up, it is possible someone is stealing your WiFi.
READ MORE - WEP key
READ MORE - WEP key

DHCP works

TCP / IP (Transmission Control Protocol / Internet Protocol) is a group of protocols that govern data communications computers on the Internet. Computers that are connected to the Internet to communicate with TCP / IP, because it uses the same language different types of computers and operating systems is not a problem. PC computer with Windows operating system can communicate with Macintosh computers or the Sun SPARC running Solaris. So, if a computer using TCP / IP and is connected directly to the internet, the computer can be connected to a computer anywhere in the world that is also connected to the internet The characteristics of computer networks:
1. share hardware (hardware).
2. sharing software (software).
3. shared communication channels (internet).
4. share data easily.
5. facilitate communication among network users. Local Area Network (LAN) is the number of computers that are linked together in a specific area that is not so broad, as in an office or building.
Broadly speaking there are two types of network or LAN, the network Peer to Peer and Client-Server network. In the peer to peer network, each computer connected to the network can act both as a workstation or server. While on the Client-Server network, only one computer that serves as a server and other computers acting as workstations. Between the two types of networks each have advantages and disadvantages, where each will be explained. LAN is composed of several basic elements that include hardware and software components, namely: Physical Components Personal Computer (PC), Network Interface Card (NIC), cable, network topology Software Components Network Operating System, Network Adapter Driver, Network Protocols. Personal Computer (PC) Type used in personal computers in the network will largely determine the performance of the network. Computers with high performance will be able to send and access data in the network quickly. In the type of Client-Server network, server computer that functioned as an absolute must have higher performance than other komputerkomputer as his workstation, because the server will be responsible for providing facilities and manage the network operations. Network Interface Card (NIC) Based on the type of bus, there are several types of network interface card (nic) or a network card, the ISA and PCI. Currently there are many types of network card is used, the PCI Type Ethernet network card Type of Wiring There are several types of wiring used and can be used to apply the Network, namely: Thin Ethernet (Thinnet) Thin Ethernet or Thinnet has advantages in terms of cost is relatively cheaper compared to other types of cabling, and installation of components easier. Coaxial/RG-58 thin cable length between 0.5 - 185 m and a maximum of 30 computers connected. Thick Ethernet (Thicknet) With thick Ethernet or Thicknet, the number of computers that can be connected in the network will be more distance between the computer and can be enlarged, but the cost of procurement is more expensive wiring and installation is relatively more difficult than Thinnet. At Thicknet transceiver used to connect each computer to the network system and connectors used are type DIX connector.
The maximum transceiver cable length of 50 m, a maximum cable length of 500 m Thick Ethernet with a maximum of 100 transceiver connected. Twisted Pair Ethernet Twisted Pair cable is divided into two types: shielded and unshielded. Shielded cable is a type that has a sheath wrapping while unshielded sheath has no wrapper. For this type of cable connection using RJ-11 or RJ-45. On twisted pair (10 BaseT) networks, computers arranged in a star pattern. Each PC has a single twisted pair cable that runs to a HUB. Twisted pair is generally more reliable (reliable) than thin coax for HUB has the capability of correcting data errors and increase the speed of transmission. Currently there are several different grades, or categories of twisted pair cable. Category 5 is the most reliable and have high compatibility, and is highly recommended. Good runs at 10Mbps and Fast Ethernet (100Mbps). Category 5 cable can be made straight-through or crossed. Straight-through cable is used to connect computers to the HUB. Crossed cables are used to connect the HUB to HUB and Broadband Modem directly to a PC (without HUB). The maximum cable length Twisted-Pair cable is 100 m. Fiber Optic A network using Fiber Optic (FO) are usually large companies, because of the price and installation process more difficult. However, using the FO network in terms of reliability and speed of doubt. Speed ​​data transmission by more than 100Mbps FO media and influence-free environment. TCP / IP Because an important role in the Windows operating system as well as TCP / IP is the protocol of choice (the default) on Windows. TCP is the transport layer of the OSI model (Open Systems Interconnection), while IP is the Network layer of the OSI mode IP Address IP address is the address given on computer networks and network devices using TCP / IP.
IP address consists of 32-bit binary number that can be written as four decimal digit groups separated by dots such as 192.168.0.1. Network ID Host ID IP address consists of two parts: network ID and a host ID, which determine the network ID address of the computer network, while the host ID determines host addresses (computers, routers, switches).
Therefore the IP address of the host to provide a complete address and the addresses in the network where the host is located. Classes of IP Address For ease of use, depending on the needs of the user, the IP address is divided into three classes as shown in Table 1.2. Network ID Host ID Class 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 Class A IP address is given to the network with a very large number of hosts. 1.xxx.xxx.xxx IP range.
- 126.xxx.xxx.xxx, there were 16,777,214 (16 million) on each IP address class A. Class A IP address is given to the network with a very large number of hosts. A class on the IP address, network ID is the 8-bit first, while the 24-bit host ID is next. Thus, how to read a class A IP address, for example 113.46.5.6 is: Network ID = 113 Host ID = 46.5.6 So that means the host IP address on the network number number 113 46.5.6. Class B IP address is usually allocated for medium-sized and large networks. In the class B IP address, network ID is the first 16 bits, while the host ID is 16 bits the next. Thus, how to read a class B IP address, such as 132.92.121.1 Network ID = 132.92 Host ID = 121.1 So that means the IP address on the host number 121.1 on 132.92 network number. with a length of 16 bits of host ID, network with class B IP address can accommodate about 65000 hosts. IP Range 128.0.xxx.xxx - 191.255.xxx.xxx Class C IP address originally used for small networks (LAN). Host ID is the last 8 bits. 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. IP address allocation is basically the process of selecting the network id and the host ID is right for a network. Whether or not this exact configuration depends on the goals to be achieved, which allocates IP addresses as efficiently as possible. Domain Name System (DNS) Domain Name System (DNS) is a system that allows the host name of a computer on a network or the Internet are translated into IP addresses. In giving a name, DNS uses a hierarchy architecture.
1. Root-level domains: a top rate is displayed as a period (.).
2. Top level domain: organization category or country code eg. Com to be used by the company;. Edu for use by the college;. Gov for use by government agencies. In addition to distinguishing the use of the name by a country to another country to use such marks. Id to Indonesia or. Au for Australia.
3. Second level domains: a name for the organization or company, for example: microsoft.com; yahoo.com, and others. DHCP (Dynamic Host Configuration Protocol) IP address and subnet mask can be assigned automatically using Dynamic Host Configuration Protocol or entered manually. DHCP is used to assign IP addresses automatically on computers that use TCP / IP. DHCP works with the client-server relationship, where the DHCP server provides an IP group address that can be assigned to a DHCP client. In providing this IP address, DHCP IP address only lend it. So this last provision IP addresses dynamically. Network topology is the physical description of the pattern of relationships between network components, which include servers, workstations, hubs and pengkabelannnya. There are three kinds of commonly used network topology, ie Bus, Star and Ring. Bus Topology In the bus topology is used a single cable or cable in the center where all workstations and servers are connected. Excellence is a bus topology network expansion or addition of new workstations can be done easily without disturbing other workstations. The drawback of this topology is that if there is interference in the cable along the center of the whole network will be impaired.
1. Star Topology In the star topology, each workstation is connected directly to a server or hub. Advantage of this topology is that Star type with a separate cable for each workstation to the server, then the bandwidth or communication bandwidth in the cable will be more wide that will improve the overall network performance. And, if there is an interruption in the cable path interference will only occur within the communication between the workstation is concerned with the server, the network as a whole is not impaired. The weakness of the star topology is the need for larger cable than other topologies.
2. Ring Topology In the ring topology all workstations and servers are connected to form a circle or ring pattern. Each workstation or server will receive and pass information from one computer to another, if the addresses match then the information is received and when the information is not to be missed. The drawback of this topology is each node in the network will always follow and manage the information that is passed in the network, so that if there is interference in a node then the entire network will be disrupted. Ring topology excellence is not the collision or the collision of data transmission such as the bus topology, since only one node can transmit data at a time. Network Adapter Card (LAN Card) Each network card will have a driver or program that serves to activate and configure the network adapter is adapted to the environment in which the network card is installed so that it can be used to perform data communication. Network Operating Systems Required to manage a network of any network operating system. Network operating systems can be divided into two types based jaringannnya, the client-server operating systems and network operating systems peer to peer.
1. Client-Server Network Servers are computers that provide facilities for other computers on the network and client computers that are receiving or using the facilities provided by the server. Dijaringan Server client-server type referred to as pure Dedicated Server acts as a server that provides the facility to the workstation and the server can not act as a workstation. Excellence Higher access speeds due to the provision of network facilities and management is done exclusively by a single computer (server) that is not burdened with other tasks as workstations. Security system and network administration is better, because there is a user who served as a network administrator, who manages administration and network security systems. Better data backup system, because the client-server network backup is done centrally on the server, which will backup all the data used in the network. Weakness
1. Operational costs are relatively more expensive. 2. It takes a special computer-enabled one more to be assigned as a server. 3. Survival is highly dependent on the network server. When the server to crash the whole network will be disrupted.
 
2.1. 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 (like the one drawn below)
2. Double-Click the 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 to exit the Properties dialog box Local Area Connection Properties
5. Double-Click Internet Protocol (TCP / IP) in the Local Area Connection dialog box to exit the Properties dialog box recently: Internet Protocol (TCP / IP) Protocol Enter the IP address data as shown above. Data IP Address every UAD will be different and unique (not to be equal between the AUD Campus Campus III with other UAD). The IP data, will be provided during the installation of Broadband is complete (when network activation) IP data is most needed by each PC that will be set in each remote UAD is as follows: 
1. À Default Gateway IP Address from the Broadband modem. Moment came after activation.
2. IP Address IP Address à this is a class with a Broadband Modem IP (IP Default Gateway) later.
3. Subnet Mask à Data Block IP to be given, it must ingclude-right-clicking the data the Subnet Mask.
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 RUN to exit the dialog box, and then type CMD to exit the dialog box a new "command"
7. In the dialog box "Command" earlier, type: ipconfig If the computer has not been connected Ethernet from the LAN, it will come out the result as shown below.

7.1. If the PING test is done when the conditions have not been connected to the LAN Computer, will get the results as shown below.
7.2. Once the computer is connected to LAN, type IPCONFIG / ALL to see the IP address attached to the computer user. The result will be as shown below. If the ping test results obtained (Request timed out), might be a problem in the local network. Problem could there be of the following: - Connector cable network (wired LAN) installed less tight. Tighten à wiring connections to the LAN port and the Ethernet Hub to the LAN PC Card - Wired LAN is not good (no pin-pin connection cable that broke in the middle) Replace with another great LAN cable - Port Ethernet Hub which is not good (loose or bad contact) à Try moving the port If the ping test results obtained as shown above (Reply from xxxx), we can be sure that the network is operating normally. Every user on the remote network UAD, expected at least, can do action as above. UAD is the target user in ensuring local network connected to the LAN IP of Ethernet Broadband Modem Gateway is a network of leading UAD UAD Center Network Server and Internet. If a PC user has to perform ping test as above, and get results Reply from xxxx à (Ip modem), then surely the LAN network in the UAD no problem. After making sure in the LAN network is not problematic, in UAD user is directed to the TEST PING IP Address Server Center. How to perform ping test is the same as the ping test IP Modem on a local network. The difference is only in the IP ADDRESS that will ping the IP address entered in the computer's central office, or the IP address on the Internet. Furthermore dilakuka test application - Internet applications.
READ MORE - DHCP works
READ MORE - DHCP works
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