Introduction to Linux Security

Security is the most important concern of the businesses around the world. In a LAN/WAN network environment security includes monitoring computer network, logging, encrypting files, auditing, firewall, password authentication, cryptography, intrusion detection system, SSL, managing the access control and using the troubleshooting tools and techniques. In this article, I have explained some of the most important security aspects in Linux such as physical security, local security, password authentication, Email security, kernel security, securing web server and wireless network security.

Security Enhanced Linux (SELinux) is a Linux feature that provides a variety of security policies by using the Linux security module in the Linux Kernel. The security mechanisms that are implemented in the SELinux support a large number of security policies. SELinux is a set of security policies that secures the Linux at every level.

Email Security

Email has become the most important communication medium for the normal web users and corporate organizations. Sometimes email accounts are gets attacked by the spammers that regularly sends unwanted, advertisement based and phishing emails. Email bombing and spamming is characterized by continuously sending mass emails to a targeted email address. In some cases, the email messages are relatively some large to consume the system resources, filing the disk and using the network connections. Email spamming is the problem of hundreds of thousands internet users.

Email Spamming/Bombing is also combined with the email spoofing. If you find that your system suddenly becomes slow which checking the email, this means that someone is trying to process and send a large number of messages. The best security and preventive measure is to identify the source of the spam emails and configure your router, email client program to block the emails from that addresses.

Network Security

Many techniques are being used to monitor, protect and troubleshoot your Linux network. A large number of network monitoring tools are available and, Nagios Host and Service Monitoring, Saidar, Netmrg, Munin, Oreon, Mon and Zabbix are some of them. Zabbix monitors all the activities on your Linux network, such as network traffic flow, bandwidth utilization, resources allocation and troubleshooting.

With Nagios you can prepare a robust, manageable and capable network monitoring system including configurations, server preparation, software compilation and installation, apache security preparation and software download and extraction.

Web server Security

There are plenty of ways by which you can secure of Apache Web server.

Make sure that apache is running under it’s own user account and group.

Turn off directory browsing.

Turn off server side includes.

Turn off multiple options.

Run Mod_security.

Disable any unnecessary modules.

Lower the timeout value.

Limit the size of XML body.

Limit the concurrency.

Limit access by IP address.

Adjust the keep Alive settings.

Run Apache in Chroot environment

Securing Firewall

Firewall is a security wall or barrier that prevents a computer network or gateway computer from unauthorized access. A firewall is a facilitator and mediator at the same time and it is a combination of two network functions i.e. proxy and gateway. There are different types of firewalls that can be used in Linux such as packet-filtering, ipchains, stateful, and layered.

A good firewall is an important part of the network security. A Linux firewall turns off the unused ports and listens to the open network ports. Linux firewall is based on the net filters, which is set of loadable kernel modules. Smoothwall Express and Smooth Guardian are two commercially available firewall software for Linux.

Introduction to Computer Network Protocols

The word protocol is derived from the Greek word “protocollon” which means a leaf of paper glued to manuscript volume. In computer protocols means a set of rules, a communication language or set of standards between two or more computing devices. Protocols exist at the several levels of the OSI (open system interconnectivity) layers model. In the telecommunication system, there are one more protocols at each layer of the telephone exchange. On the internet, there is a suite of the protocols known as TCP/IP protocols that are consisting of transmission control protocol, internet protocol, file transfer protocol, dynamic host configuration protocol, Border gateway protocol and a number of other protocols.

In the telecommunication, a protocol is set of rules for data representation, authentication, and error detection. The communication protocols in the computer networking are intended for the secure, fast and error free data delivery between two communication devices. Communication protocols follow certain rules for the transmission of the data.

Protocols Properties

Different protocols perform different functions so it is difficult to generalize the properties of the protocols. There are some basic properties of most of the protocols.

• Detection of the physical (wired or wireless connection)

• Handshaking

• How to format a message.

• How to send and receive a message.

• Negotiation of the various connections

• Correction of the corrupted or improperly formatted messages.

• Termination of the session.

The widespread use of the communication protocols is a prerequisite to the internet. The term TCP/IP refers to the protocols suite and a pair of the TCP and IP protocols are the most important internet communication protocols. Most protocols in communication are layered together where the various tasks listed above are divided. Protocols stacks refer to the combination of the different protocols. The OSI reference model is the conceptual model that is used to represent the protocols stacks. There are different network protocols that perform different functions. Following is the description of the some of the most commonly used protocols.

HTTP (Hyper Text Transfer Protocol)

Hypertext transfer protocol is a method of transmitting the information on the web. HTTP basically publishes and retrieves the HTTP pages on the World Wide Web. HTTP is a language that is used to communicate between the browser and web server. The information that is transferred using HTTP can be plain text, audio, video, images, and hypertext. HTTP is a request/response protocol between the client and server. Many proxies, tunnels, and gateways can be existing between the web browser (client) and server (web server). An HTTP client initializes a request by establishing a TCP connection to a particular port on the remote host (typically 80 or 8080). An HTTP server listens to that port and receives a request message from the client. Upon receiving the request, server sends back 200 OK messages, its own message, an error message or other message.

POP3 (Post Office Protocol)

In computing, e-mail clients such as (MS outlook, outlook express and thunderbird) use Post office Protocol to retreive emails from the remote server over the TCP/IP connection. Nearly all the users of the Internet service providers use POP 3 in the email clients to retrieve the emails from the email servers. Most email applications use POP protocol.

SMTP (Simple Mail Transfer Protocol)

Simple Mail Transfer Protocol is a protocol that is used to send the email messages between the servers. Most email systems and email clients use the SMTP protocol to send messages to one server to another. In configuring an email application, you need to configure POP, SMTP and IMAP protocols in your email software. SMTP is a simple, text based protocol and one or more recipient of the message is specified and then the message is transferred. SMTP connection is easily tested by the Telnet utility. SMTP uses the by default TCP port number 25

FTP (File Transfer Protocol)

FTP or file transfer protocol is used to transfer (upload/download) data from one computer to another over the internet or through or computer network. FTP is a most commonly communication protocol for transferring the files over the internet. Typically, there are two computers are involved in the transferring the files a server and a client. The client computer that is running FTP client software such as Cuteftp and AceFTP etc initiates a connection with the remote computer (server). After successfully connected with the server, the client computer can perform a number of the operations like downloading the files, uploading, renaming and deleting the files, creating the new folders etc. Virtually operating system supports FTP protocols.

IP (Internet Protocol)

An Internet protocol (IP) is a unique address or identifier of each computer or communication devices on the network and internet. Any participating computer networking device such as routers, computers, printers, internet fax machines and switches may have their own unique IP address. Personal information about someone can be found by the IP address. Every domain on the internet must have a unique or shared IP address.

DHCP (Dynamic Host Configuration Protocol)

The DHCP or Dynamic Host Configuration Protocol is a set of rules used by a communication device such as router, computer or network adapter to allow the device to request and obtain and IP address from a server which has a list of the larger number of addresses. DHCP is a protocol that is used by the network computers to obtain the IP addresses and other settings such as gateway, DNS, subnet mask from the DHCP server. DHCP ensures that all the IP addresses are unique and the IP address management is done by the server and not by the human. The assignment of the IP addresses is expires after the predetermined period of time. DHCP works in four phases known as DORA such as Discover, Observe, Request and Authorize

IMAP (Internet Message Access Protocol)

The Internet Message Access Protocol known as IMAP is an application layer protocol that is used to access to access the emails on the remote servers. POP3 and IMAP are the two most commonly used email retrieval protocols. Most of the email clients such as outlook express, thunderbird and MS outlooks support POP3 and IMAP. The email messages are generally stored on the email server and the users generally retreive these messages whether by the web browser or email clients. IMAP is generally used in the large networks. IMAP allows users to access their messages instantly on their systems.

ARCNET

ARCNET is a local area network technology that uses token bus scheme for managing line sharing among the workstations. When a device on a network wants to send a message, it inserts a token that is set to 1 and when a destination device reads the message it resets the token to 0 so that the frame can be used by another device.

FDDI

Fiber distributed data interface (FDDI) provides a standard for data transmission in a local area network that can extend a range of 200 kilometers. The FDDI uses token ring protocol as its basis. FDDI local area network can support a large number of users and can cover a large geographical area. FDDI uses fiber optic as a standard communication medium. FDDI uses dual attached token ring topology. A FDDI network contains two token rings and the primary ring offers the capacity of 100 Mbits/s. FDDI is an ANSI standard network and it can support 500 stations in 2 kilometers.

UDP

The user datagram protocol is a most important protocol of the TCP/IP suite and is used to send the short messages known as datagram. Common network applications that uses UDP are DNS, online games, IPTV, TFTP and VOIP. UDP is very fast and light weight. UDP is an unreliable connectionless protocol that operates on the transport layer and it is sometimes called Universal Datagram Protocol.

X.25

X.25 is a standard protocol suite for wide area networks using a phone line or ISDN system. The X.25 standard was approved by CCITT now ITU in 1976.

TFTP

Trivial File Transfer Protocol (TFTP) is a very simple file transfer protocol with the very basic features of the FTP. TFTP can be implemented in a very small amount of memory. TFTP is useful for booting computers such as routers. TFTP is also used to transfer the files over the network. TFPT uses UDP and provides no security features.

SNMP

The simple network management protocol (SNMP) forms the TCP/IP suite. SNMP is used to manage the network attached devices of the complex network.

PPTP

The point to point tunneling protocol is used in the virtual private networks. PPP works by sending regular PPP session. PPTP is a method of implementing VPN networks.

OTHER PROTOCOLS

VTP, ARP, IPX, OSPF, RARP, NFS, BOOTP, NNTP, IRC, RADIUS, Soap, Telnet, RIP, SSH.

Introduction to TCP/IP

Here you will learn about Tcp ip network overview, data communication, ip addressing introduction, basic protocols, routing in the internet. TCP/IP short for Transmission Control Protocol is a suite of the communication protocols used to connect the hosts on the internet. TCP and IP were developed by a department of defense (DOD) in a research project to connect the number of networks by different vendors to form a big network of networks (the Internet).

It was originally successfully because of the services it gave, which everyone wanted to use such as file transfer, electronic mail, remote logon across a very large number of clients and server system. Several computers in a small network can use TCP/IP to communicate with each other. The IP component of the TCP/IP suites provides the routing between the two locally or remote computers.

IP forwards each packet based on a four byte, 32 bits address. TCP is responsible for verifying the correct delivery of data from the client to server. TCP also supports to detect the errors in the transmission and also triggers the data to retransmit correctly.

TCP/IP is a de facto standard of transferring the data on the network and on the internet. Each network operating systems that have their own protocols must support TCP/IP too. All the computers in a network must follow the rules to communication with each other.

TCP/IP stands for Transmission Control Protocol and Internet Protocol and it is a communication standard that defines how data travels on the internet and how network/communication devices communication with each other.

Inside the TCP/IP

TCP/IP is a not a single protocol but it is a suite of the protocols. There are the numerous protocols in the TCP/IP suite such as TCP, UDP, ICMP, DHCP, IMAP, HTTP, HTTPS, SSL, SMTP and many others.

Internet Protocol is a connectionless protocol that is used to communicate between the two computers. IP does not occupy the communication line between the two computers. With the IP communication, data is broken into the smaller pieces called packets, and these packets communicate between the two locally or remotely connected devices in a computer network or via internet. IP is also responsible for routing the packets to its destination. Routers are responsible for routing the packets towards its destination when a computer sends packets to an IP router. Data is routed towards its destination is all by a router. Router works as a post office.

TCP/IP

The TCP/IP (transmission control protocol/Internet protocol) work together in which TCP takes care communication between the application software i.e browsers whereas IP takes care of the communication between the computers. TCP breaks the data into smaller packets before they can be sent and IP sends the packets to the receivers.

IP Addresses

Each computer in a network or on internet must have a unique IP address before it can communicate with the other computer. The packets must have the address of the destination computers or devices. Each IP address is composed of 32 bits and 4 octets each packet must have an address before it can be sent to another computer.

This is an IP address 100.100.100.10 and this website http://www.example.com might have mapped with the same IP address. Without a unique IP address the communication on the internet is impossible. The numbers in the address must range between 0 and 255 in four period separated portions. Each IP address consists of 32 bits and 32 bits are consisting of 4 bytes. A computer byte can contain 256 different values e.g 00000000, 00100010, 00000111, 11111000, 01010101, 001100110 and up to 11111111.

Domain Names

Domain names are the unique identifier of a website because 12 digits numbers are difficult to remember. The name used for the web address is called a domain name e.g www.google.com, www.msn.com, www.yahoo.com all are domain names and comparatively are easy to remember instead of 12 digits numbers like, 123.220.44.240, 100.100.100.101 and 202.202.56.110. When you type a domain name in your web browser the domain name is translated into IP address by the DNS server, which is managed by your local ISPs or your corporate DNS servers.

All over the world a larger number of the DNS servers are connected with each other some are primary DNS servers, secondary DNS servers, Master DNS servers and Root DNS servers. When a new domain is registered by a domain registrar with associated TCP/IP address then DNS servers from all over the world are updated.

TCP/IP is a large collection of the different communication protocols.

TCP/IP is a large collection of different communication protocols.

A Family of Protocols

TCP/IP is a large collection of different communication protocols based upon the two original protocols TCP and IP. Each protocol in the TCP/IP suite is responsible for the different communication tasks. HTTP is responsible for the communication between the web server and the web browser. It sends requests from the client (browser) to web server and returning the web pages to the client.

HTTPS is responsible for the secure communication between the web browser and the web server. HTTPS usually handles the credit card transactions and other sensitive and secure data. SSL is responsible for the encryption of the data for the secure communication. SMTP (Simple mail transfer protocol) is responsible for sending the emails. MIME (Multi purpose Internet mail extension) is responsible for communicating the multimedia data such as, voice, video, graphics etc. IMAP (Internet Message Access Protocol) is responsible for storing and retrieving the emails.

POP (post office protocol) is used for downloading the emails from the email server to the personal computer. FTP (File transfer protocol) it takes cares of transferring the files between the computers. NTP (Network time protocol) is used to synchronize the time between the networks. DHCP (Dynamic host configuration protocol) is responsible for assigning the IP address dynamically to the network computers. SNMP (Simple Network Management Protocol) is used for administration of a computer network.

LDAP (Light weight directory access protocol) is used for storing the names and email addresses on the internet and also communicating with the Active directory in computer network. ARP (Address resolution protocol) is used to find the hardware address of a computer based on the IP address. Boot P protocol is used for starting computers in a network. PPTP (Point to point tunneling protocol) is used to make a secure tunnel in the private networks such as VPN.

TCP/IP is the Internet Communication Protocol.

A protocol is a set of rules, agreed upon methods or a communication language, which both computers understand and agree upon. TCP/IP defines the rules to communicate over the internet. Internet browsers and Internet servers uses TCP/IP to communicate on the internet .

Web browsers, Web servers, Email programs and internet address all follow TCP/IP. An IP address is a part of the TCP/IP protocols.

What is Virtual Private Network

VPN (Virtual Private Network)

Learn how to setup vpn, step by step instructions, how virtual private network works, windows configurations, and hardware and software requirement in the virtual private network. A virtual private network is a private network that uses public network (Internet) and maintains privacy and security procedures through encryption and other security procedure. VPN’s provides an alternative dedicated private network connection for the offices and companies.

Many businesses around the world are using VPN to connect their office servers from other locations such as home etc. Virtual Private Nework uses PPTP (Point to Point Tunneling Protocol to allow Windows and Mac users to connect to the PowerElf servers from the other locations.


PPPT provides a secure 128bit encrypted connection from the local computer to the VPN server. In VPN, not only the data is encrypted but the source and destination network address is also encrypted.
VPN uses internet as a medium to connect to the remote networks and sites and allows virtual connections.

Virtual Private Nework is an alternative method to connecting the office network or a LAN. Internet is a public domain and anyone with a computer, a phone line, modem and internet service can access it.

VPN uses a set of the security methods, such as encryption, passwords, firewalls and other security procedures. VPN may be composed of a number of servers and sites.

The most common Virtual Private Nework is a remote-access VPN, which creates a secure tunnel from your computer and your company’s server.

In some cases you don’t even need to have internet access but you only need a computer, telephone line, modem and software, which network administrator might have installed on your computer or you will be provided with the instructions that how to configure PPTP.

After successfully configuring the PPTP, you will be able to dial the company’s server and access it by creating a VPN. In Virtual Private Nework, remote computers act as they are in the same and secure local network.
There are a number of advantages and disadvantages of the VPN connections.


Advantages

• It allows and makes you able to connect and access your company’s computer, while you are at your home or other remote location. This is the same way as you access your company’s computers in your office.
• It is almost impossible for someone to interfere or intrude in your VPN network tunnel
• You can even connect to your company’s network from all over the world if you have installed and configured VPN client software on your laptop.

Disadvantages

The setup of the Virtual Private Nework connections is comparatively more complicated than the normal network connections. VPN can work around the network products of different companies but connecting to a non-NETGEAR product will add some difficulty.

You will have to follow the company’s own policies and procedures while connecting to its network through VPN. VPN goes between a computer and network or a local LAN and a remote network using routers. Each end of the connection is an VPN endpoint. The connection between the two VPN networks is called VPN tunnel.

All NETGEAR router supports VPN pass through. Pass through means that a router does not stop VPN traffic. The purpose of VPN is to prevent the data between two computers or networks being altered.
The whole purpose of VPN is to prevent data being altered, so, for example, a pass through router that is also running NAT will break the VPN connection.

VPN Essentials

For setting up the Virtual Private Nework connection you need the basic equipment and the VPN account from your Internet Service Provider. The latest operating systems like Windows 2000, Windows 2003 server or professional does not require the separate VPN client software. But if you have old operating systems like Windows 95/98, you will require additional software for VPN.


Hardware

• PC with the processor speed of more than 300 MHZ.
• RAM: 128MB although 64 MB is the minimum support but it may limits many features and of VPN.
• 1.5 GB available disk space.
• A dial up, cable modem, ISDN or any type of modem is required. The modems with more speed and good for faster transfer of data.

Software
Any Virtual Private Nework client software.

Internet Account

You will require a VPN account with your ISP with a password and dedicated IP address for the security connection and encryption purposes.


Virtual Private Nework Accessories

An increasing number of businesses are opting for the VPN solutions. Different vendors are adding the different functionalities in the hardware and software such as encryptors in the hardware. Some are adding security and firewall related capabilities both in software and hardware.

Virtual Private Nework Working

There are many aspects of the working of the VPN and it depends on the software, hardware and the architecture of the VPN connection. Each VPN connection type has it own features with respect to security, scalability and quality of service. There are 2 main types of the VPN connections such as individual computer to LAN and LAN to LAN connections.

The purposes of the protocol involves in VPN are as follows. • The encryption of data at the sending end.

• Creation of a tunnel where data in the form of packets is encapsulated in the form of TCP/IPnetwork.
• The decryption of the data at the receiving end.
• Other security measures included password security, firewall and the encryption of the host and remote computers or networks IP address.

Introduction to Mobile Technology and Communications

Here you will learn about mobile technologies, mobile phones, wireless communication introduction, overview to gsm, gprs, sms and mms reviews. A cellular or mobile phone is a long range portable electronic device for communication over long distance.

Current Mobile Phones can support many latest services such as SMS, GPRS, MMS, email, packet switching, WAP, Bluetooth and many more. Most of the mobile phones connect to the cellular networks and which are further connected with the PSTN (Public switching telephone network). Besides mobile communications, there is a wide range of mobile products available such mobile scanners, mobile printers and mobile labelers.

Mobile Network Technology

Mobile phones and their network vary very significantly from provider to provider and country to country. However the basic communication method of all of them is through the electromagnetic microwaves with a cell base station. The cellular companies have large antennas, which are usually mounted over towers, buildings and poles. The cell phones have low-power transceivers that transmit voice and data to the nearest sites usually within the 5 to 8 miles (8 to 13 kilometers away).

When a mobile device or phone is turned on, it registers with the mobile telephone exchange or switch. It is a unique identifier and is alerted by the mobile switch when there is an incoming phone call.

The handset listens for the strong signals from the nearest base stations. When a user moves, the mobile device handoff to various nearest sites during phone calls or while waiting between calls it reselect the nearest cell phone sites.

Cell sites have relatively less power radio transmitters. They broadcast their presence and relay communications between the mobile handsets and the switch. On the other hand, the switch connects the call to the same or another mobile network or subscriber.

The dialogue between the mobile phone handset and the cell phone site is a stream of the digital data, which includes the digitized audio. This technology depends on the same system as of mobile phone operator. Some mobile phone technologies have adopted the AMPS for the analog communication and D-AMPS, CDMA2000, EVDO, GSM, UMTS, and GPRS for the digital communication. Each mobile phone network has a unique radio frequency.

There are different mobile communication methods, such as SMS, WAP, WLAN, WIFI, GPRS, Bluetooth, Infrared, IrDA and I-Phone etc. Mobile phones are different from the cordless telephones because they only operate within the specific range. Many types of the mobile computers have been introduced including the Laptop computer, Subnotebook, Portable data terminal (PDT), Personal digital assistance (PDA), Tablet personal computer and smart phone.

Mobile phone features

Mobile phones have features beyond sending text messages and making the short or long distance voice calls, the other features including internet browsing, mp3 playback music, email, personal organizer, built in cameras, MMS, PPT, SMS, call registries, built in games, voice mails, downloading, video call, Bluetooth, infrared and they also serve as the wireless modem for a pc. In many countries of the world such as Australia, Pakistan, India, Maldives and Israel the incoming calls are free. However, in Canada, Hong Kong and the United states a person can be charged per minute for the incoming calls. Few mobile phones carriers in the United States are beginning to receive unlimited phone calls. Mobile technology has both negative and positive impact on every day’s life.

Health impact

Since the invention of the mobile phones many concerns have been raised about the potential health from the mobile phones. Study at the Danish Institute of cancer epidemiology does not show any link between cancer and mobile phone usage. This study only covers the analog phone usage till 1995. However the study by the International Agency for research on cancer shows link between cellular phone usage and tumor frequency.

Mobile dating

Mobile dating also known as cell dating and it allows users to chat, meet and possible involves in romance by SMS, chatting and the web. These services allow their subscribers to provide information about themselves in a short profile and which is stored in the cell phone sets as a dating ID. The users can search for the other IDS or call at a number given to them by the service. Users can find others with the criteria of age, location and gender. Most of these sites are free to use but the standard fees of SMS and dating service charges can apply per minute. Mobile dating websites focus attention on users that share the same social network and proximity.

Some cellular companies offer services such as homing device. This service alerts the users when someone is within the thirty feet of the user. Some cellular companies use Bluetooth technology to connect the users in the bars, clubs and social gatherings and this service is called proximity dating. These services are more popular in European countries, United States, Australia and Canada. Mobile dating websites are gaining popularity.

Mobile Learning

M-learning’ is the follow up of E-learning and which originates from D-learning (distance learning). M-learning is the delivery of education to the students who are not having fixed location or who prefer to use mobile phone technology for learning. The rapid growth in the mobile and communication sector make it possible to develop new forms of education. M-learning means delivery of education by means of the mobile phone devices, PDAs and audio players. M-learners seek the lessons in the small format.

Mobile software

Windows mobile, Palm OS and Symbian OS supports typical application binaries as found on the personal computers. Windows mobile also supports portable executable format which is associated with the .NET Framework. Both Windows Mobile and Palm OS provide free SDK and integrated development environment for the developers. BREW is another format which gives complete control of the handset and access to all its functions. Java (J2ME, Java ME) runs atop a virtual machine, which allows reasonable functionalities. Because of the extra security and compatibility, it is quite simple to write, distribute and execute the mobile Java applications.

Mobile Internet

According to the many sources, one of the major factors of the usage of mobile internet is its speed. Mobile internet has faster connection. Due to this fact, many users tend to use mobile internet. The introduction of the 3G cards has a competitive high speed. All the current service providers and trying to increase their bandwidth to get more customers. The numbers of mobile phones that are cable of surfing the net have been increasing rapidly. One of the greatest problems when browsing the net on the cell phones is the small size of the screen. Because of this many developers are developing the websites that can easily be seen on the cell phones as well.

Mobile society.

Ongoing debates about the cyberspace, e-computing and E-commerce have suggested that the online world somehow will be dramatically different from the life in the analog world. It is true that E-commerce continues to grow and the specific locations of the persons and businesses do not matter that much anyone. This is also true that now we are seeing forums, blogs, discussion groups and social network to re-socialize and form new tribes on the internet. It seems that everyday we are increasingly connected via technologies such as email, cellular phones, instant messaging and all of these technologies are increasingly interconnected with each other. When we communicate on our cell phones, we are also mobile in the sense that we can move freely while in the constant communication.

Here Mobile Phones you will learn about the mobile technologies, cellular phones, wireless communication introduction, overview to gsm, gprs, sms and mms reviews.

An Overview of the Wireless Networking

Here you will find wireless networking tutorials, what is wifi, general security overview, wlans, wpans, wmans, wep and wireless access control overview. Whether you want to make a phone call from your mobile, received a message on your pager, checked your email from a PDA we have come across a wireless data or voice network.

If a user or a company wants to make a data portable then Wireless networking is the answer. A wireless networking system can avoid the downtime, which may be caused in the wired network. A wireless network is also save your time and efforts in installing the lot of cables.
Also, if you need to relocate a client machine in your office, you only need to move the computer with wireless network card.


Wireless networking is very useful in the public places, libraries, hotels, schools, airports, railway stations where one might find wireless access to the internet. A drawback in the wireless internet is that quality of service (QOS) is not guaranteed if there is any interference then the connection may be dropped.


Wireless Network Types

Wireless Local Area Networks (WLANS)

WLANS allow users in local area, such as in a university or a library to form a network and gain wireless access to the internet. A temporary network can be formed by a small number of users without the need of access point; given that they do not need to access the resources.


Wireless Personal Area Networks (WPANS)

There are two current technologies for wireless personal network Bluetooth and Infra Red. These technologies will allow the connectivity of personal devices within an area of 30 feet. Infra Red requires a direct line and the range is less as compared to Bluetooth technology.

Wireless Metropolitan Area Networks (WMANS)

WMANS allow the connectivity of multiple networks in a metropolitan area such as building in a city. The network connectivity is the alternative of copper or fiber cabling.

Wireless Wide Area Networks (WWANS)

WWANS or Wireless Area Networks can be maintained over large areas such as in different cities or between different countries, via multiple satellite systems or antenna sites. The types of system are called 2G systems.

The following table shows the range those different types of wireless network covers.
Network Meter
Personal Area Network 0-10
Local Area Network 0-100
Wide Are Network 0-10000
Security in Wireless Networking
The following different types of security methods are available in the wireless networking.

Wired Equivalent Privacy (WEP)

Wired Equivalent Privacy is intended to stop the interference of radio frequency that is signaled by unauthorized users and this security measure is most suitable for the small networks. There is not key management protocol and each key is entered manually into the clients that’s why this is very time consuming administrative task. The WEP security method is based on the RC4 encryption algorithm. In the WEP all the client computers and Access points are configured with the same encryption and decryption keys.


Service Set Identifier (SSID)

Service Set Identifier (SSID) acts a simple password by allowing WLAN network to be split up into different networks and each having a unique identifier. These identifiers are configured in the multiple access points. To access any of any networks, a computer is configured in such a way that each is having a corresponding SSID identifier for that network. If the SSID match between the two computers or networks then access is granted to each other.


Media Access Control filtering (MAC Access Control)

A list of the MAC addresses of the client computers can be inputted into an Access point and only those computers are granted to give the access to the network. When a computer makes a request, its MAC address is compared to the list of the MAC addresses to the Access point and based on this access permission granted to deny.
This is a good security method but it is mainly involved in the small wireless networks because there is more manual work is involved of entering the MAC address into the Access point.

Bluetooth

Bluetooth is a simple type of the wireless networking that operates in the digital devices, like mobiles phones, personal computers, PDA, Laptops, digital camera, MP3 players and other Bluetooth enabled devices to form a small network. In the Bluetooth technology eight devices can be connected to each other at the same time. Bluetooth can also be found in the headsets, hands-free kits, wireless keyboards and mouse. Bluetooth technology was invented by Ericsson in 1994 and after four years in 1998 some major mobile phone companies such as Nokia, Ericsson, Intel and Toshiba formed a group to promote this technology.

Bluetooth technology falls in the category of personal area networking because it operates in the range of 30 to 300 feet. Bluetooth uses the radio waves technology, which is not very expensive and has low power consumption. Many different companies are intended to add the Bluetooth chip in their digital devices. Bluetooth technology is getting very popularity because of its low cost and portability.


The Future of Wireless Networking

WLANS wireless networking type is very popular in home networking and more than 20 percent homes with broadband internet are using WLANS and this number is increasing. In a general estimate worldwide hotspots have now reached more than 30,000 and will grow about 210,000 in the next few years. Most large hotels already offer Wi-Fi and the business travelers are willing to pay wireless access. 802.11 is the next Wi-Fi speed standard is set to offer bandwidth around 108Mbps and is still under development. With the speed of 70 Mbps and a range up to 30 miles, the 80216 standard, known as WiMAX is sure to get boost.

Some Tips & Tricks

• When purchasing a wireless NIC card try to get one that is having external antenna. When you are out and using Wi-Fi enabled laptop, disable Microsoft file and sharing, which enables other computers in a network to access data and resources on your computer. In this way, your computer or laptop will be saved from hackers.
• If you are concerned about the interference from the other wireless access point set the AP and wireless computers to use a non-overlapping channel.
• Change the configuration interface password of the access point before you enable it.
• Only buy an access point that is having upgradeable capabilities. By this way you can take the advantage of security enhancements.
• Keep the access point up to date.

What is GSM ?

Here you will learn about gsm network technology introduction, cellular operators, cdma, voice mail, sim cards, dual band, quad band, communication channel, wireless communication and gprs overview. GSM was first introduced in the Finland in the year of 1991. GSM mobile phones operate on the TDMA systems. In the TDMA (time division multiple access system), multiple users can access single radio frequency without any interference. GSM is now the de facto standard for the mobile communication in the world.

The GSM (Global System for Mobile Communications) is a hugely successful wireless technology in the world. GSM has become the world’s largest growing communication technology and it has been expand in more than 214 countries of the world. The TDMA technology provides the individual time slot within a specific channel for each user.


GSM leads the world as the fastest growing mobile/wireless digital technology that is most reliable and is available in the marketplace today. GSM provides the integrated high-speed data, fax, voice mail, paging and short messages services features. GSM offers the secure communication, privacy and fraud prevention.

After subscribing to the GSM service, you can use your phone at your home, office, across the continent or around the world with the country specific SIM cards. GSM operates on the different frequency levels like 900 MHz, 1800 MHz or 1900 MHz.

1900Mhz is used in the North America and 1800 MHz is for the other locations. Different mobile phone networks around the world operate at different frequencies. If you wish to use your mobile phones outside of your GSM frequency range then you should use a mobile/handset that support multiple frequencies. Before buying a mobile phone, make sure that it is compatible with the different bands of the GSM.

Dual-band – A dual band phone operates at different spectrum like 900 MHz and 1800 MHz. Dual-band GSM works in Europe, Asia, Africa, Australia and Sound America. Tri-band – A tri band phone operates on the three different frequency levels like 900 MHz, 1800 MHz and 1900 MHz. This means that you can use your mobile phone in Europe, Asia, Australia, Africa and North America.

Quad-band – A quad band GSM capable phone allows you to roam almost everywhere in the world. It covers the different frequency ranges like 850 MHz, 900 MHz, 1800 MHz and 1900 MHz. 99% countries in the world use the GSM standard and it seems that GSM will eventually be the only cell phone standard in the mobile communication world. GSM provides the best voice quality and standard.

Today, there are more than 720 GSM mobile networks across the more than 214 countries. According to the recent statistics, there are more than 2 billion users of the GSM in the world. Major GSM using countries includes China, Russia, United States and India. A mobile phone can be a bewildering affair for a traveler. It is mostly incompatibility with the network of your visiting country, since every country in the world has different frequency band of operation. With a GSM enable mobile phone you can access more than 214 countries around the globe.

GSM is a state of the art technology offering voice, data, fax and SMS capabilities. Most of the mobile phone operators now offers email to SMS service by which you can receive the important news, flight status and other useful information on your mobile phone. Many operators give access to the ISDN services by which fast data transmission is possible. Many other offers GPRS (Global Packet Radio Service) with this service you can connect to the high speed data communication channel like 9600 bps. The two major GSM service providers in the US are the T-mobile and Cingular.

Introduction To Windows Networking

What is Windows Networking?

The term networking covers a broad range of the topics and technologies. A computer network is segmented into different parts to share the data and resourced between the different computers of a network. Microsoft has released the operating systems that have the networking capabilities so Microsoft Windows 98, Microsoft Windows 2000, Windows 2003, Windows XP Professional and Windows Vista all are the network operating systems.

 

All these operating systems have built inn capabilities of files and printer sharing, security, network administrative control, protocols support such as TCP/IP, NetBIOS, IPX/SPX and network hardware support.

Naming Computers

All computers in a Windows based network requires a unique name for their identification i.e. the name of the computer A cannot be assigned to the computer B and so on. Assign a meaningful computer name to all the computers and the name should be easy to remember.

All the names should be configured properly and ensure that the name is not longer than the 15 characters and they contain no spaces in them. Also try to avoid the special names while naming the computers such as / \ *,:,. To assign a computer name in Windows XP and Windows 2000 do the following things.

1. Right click on the My Computer.

2. Click Properties

3. Click on Computer name.

4. Assign a unique and meaningful computer name.

Naming Workgroup and Domains

A Windows based computer network can be a workgroup (Peer to Peer) or domain (client/server). You can make your computer a part of the workgroup or a domain. If you have centralized server then your computer will be part of the domain and if you have no server then all computers will be having peer to peer networking. In both cases, while joining your computer to a domain or a workgroup always assign unique, sequenced, memorable and meaningful names to the computers. Do not use duplicate names and the special characters such as / \ *,:,,. In order to join a computer to a domain or workgroup in Windows 2000 and Windows XP Professional do the following.

1. Right Click on My Computer

2. Click Properties

3. Click on Computer Name

4. In Workgroup or domain, enter the name of the workgroup or domain.

If everything is correct such as unique computer name, unique IP address, correct workgroup or domain name then you computer will be the part of the workgroup or domain in the few seconds and you will be see a welcome to domain or workgroup message and will be prompted to restart the computer name.

Files Sharing

Being on network computer files and printer sharing is a must. To enable the files and folder sharing in Windows XP Professional 2000 and Windows 2000 do the following.

1. Right Click on the folder name you want to share.

2. Click on the properties.

3. Click Sharing.

4. Click on Share this computer on the network.

5. Assign a shared computer name.

You can set the sharing rights for the users and also control the shared folder access by allowing and denying permissions to specific users or groups. If you want to share the individual files, you can put the files in the same shared folder. All the files and folders in the parent shared folder will be automatically shared.

Network Cable Errors in Windows

If your computer network cable is not working properly, you will see a repeated message or pop up “network cable is unplugged” on your desktop and the blinking status lights of the network will also stop blinking. There can be many causes of this problem and you can fix this error with these simple tips. If you have another Ethernet adapter installed but not using it, then disable it by right clicking on the monitor icons on the right side of the desktop and select the disable option. Check both ends of the cables and ensure that the RJ 45 connectors are properly inserted in the LAN card and in the Hub/Switch. Update the drive of the LAN card from the vendor’s website and if the problem still exist then replace the cable with new one. If the problem is still not resolved then replace the LAN card with a new one and try to use a new hub or switch and put cable’s one end into it. By these simple steps, you will be able to trace out and troubleshoot the problem.

Introduction to Windows Firewall

Windows firewall is a protective layer or boundary that monitors the in and out traffic from your network and internet. The firewall is a protective and defensive boundary against the intruders and unauthorized persons. You can enable the firewall in XP Professional with these simple steps.

1. Click Start > Settings > Control Panel

2. Windows Firewall > Double click.

Network Troubleshooting Tips

If you find a communication failure error in the TCP/IP network then try to find and troubleshoot the errors with the following methods.

1. Make sure you can ping the other computer by name.

2. Make sure you can pint the other computer by IP address.

3. Make sure you have assigned unique IP address and computer name to all the computers in the network.

4. Make sure you have assigned the correct gateway, subnet mask, DNS and DHCP addresses.

5. For troubleshooting purpose try to uninstall any firewall software and see if the problem is resolved.

Windows Network Security

Security a computer network should be the top priority of the network administrators, system managers and security specialists. You can secure your computer network by doing these things such as installing the updated operating system, up-to-date antivirus program, event log monitoring, encryption, group policy management, patch management, security scanners, auditing, firewall security, web application security, web content filtering and controlling the access to only the authorized users.

Introduction to ISDN Line

Find here ISDN Network, introduction to ISDN line, bri, t1 lines, d1 lines, primary rate interface, connection time and setup instructions. The regular phone line, which is used at home and offices is an analogue phone line. Your voice is picked up by telephone mouthpiece and then sent down the phone line as an analogue wave. Regular modem converts the digital signals of the computer into the analogue waves, which then travels on the regular phone lines.

 

At the other end, modem receives that analogue signals and then convert back into the digital signals that are understandable by a computer ISDN network is a digital communication system that is capable of producing the maximum transmission speed of 1.4Mbps. 128Kbps speed is however more common in the digital technology. It's a international standard for sending data, voice, video over regular digital telephone lines. ISDN uses UTP (unshielded twisted pair cable) for transmission.

Types of ISDN Network

There are two basic types

• Basic Rate Interface (BRI) – It consists of two 64 B-channels and one D-channel for transmitting control information.
• Primary Rate Interface (PRI) -- It consists of 23 B-channels and one D-channel (for U.S.) or 30 B-channels and one D-channel (for Europe).

The actual version of ISDN employs base band transmission. Another version, called B-ISDN, uses broadband transmission, which is able to support transmission rate of 1.5 Mbps. B-ISDN mainly requires fiber optic cables.

To access the B channel, it is necessary to subscribe the ISDN phone line. Customers are also required to have some special ISDN devices, which are known as terminal adapters, which are used to communication with the telephone company switch or other ISDN devices.

How ISDN Works

In an analog network, a regular telephone line that is provided by the telephone company supports a single transmission channel, which normally can carry only one service, voice, data or video at a single time. With ISDN, this same pair telephone line is logically divided into the multiple channels. A typical line has two channels.

The first type of channel is called B channel. This channel can carry about 64Kbps of data. Typical ISDN line has 2 B channels. One channel is used for voice and other channel is used for data communication. This data/voice transmission process occurs on the regular one pair copper wire.

The second type of channel is used for link and call setup. This channel is known as D channel or Delta Channel.

The third channel has only 16Kbps of bandwidth.

Advantages

Speed

There is an upper limit of the speed in the commonly used dial up modems, which is 56kbps. But due to the quality and other factor, the maximum attainable speed is 45kbps.

ISDN allows multiple digital channels to operate simultaneously through the same regular one pair copper wire. If the telephone company supports the digital connections then a change can occur. The digital signals instead of the analogue signals, transmitted across the telephone line. In the digital scheme, there is much more data transfer rate than the analog lines.

Multiple Devices

A separate telephone line is required for using the fax, telephone, computer, router and live video conferencing systems. A separate line is required for each device. ISDN network lines can handle the multiple devices on the single line. Up to eight devices such as, computer, faxes, cash registers, credit card readers or other devices can directly be connected to a single ISDN line, all these devices can work simultaneously.

Connection Time

V.34 modems typical take 30-60 seconds to establish a connection and on the other end an ISDN call usually takes less than 2 seconds to establish a connection.

Disadvantages

There are some disadvantages of the ISDN lines, which I have discussed below.

1. ISDN is more expensive than the Plain old telephone system.
2. The telephone company and the ISDN user both are required to have the specialized digital devices.

ADSL VS ISDN

There is a noticeable difference between the two services.

• ISDN provides two voice channels or one 128Kbps data channel while ADSL is basically a data pipe.
• The power for ADSL is sent by carrier over copper wire; as with the local phone service. The line works even when local power fails. This is an advantage over the ISDN lines, which requires the local power supply.

What is a Web Server?

Learn Web server software overview, how to configure, how it works, apache, tomcat. Web server is a computer including a software package that provides the specific services to the client computers. Web server delivers the web pages. Every web server has an IP address and a domain name. If you sends a request through your browser for this website http://www.networktutorials.info, the request goes to the server whose domain name is networktutorials.info.

The server fetches the index or main page of the website and sends it to your browser. Web-based servers are used for hosting the websites. One web server can hosts thousands for one sites. But in the hosting companies there are number of the web servers for load balancing and sharing the other services.

The web hosting companies offer different types of hostings services including Ecommerce hosting, CPanel hosting, PHP hosting and reseller hosting.

A computer can be act as a web server by installing and configuring the server software and connecting the computer to the Internet. Normally, web server computers have to be turn on (online) for almost all the day.

There are many software applications that are used as the web server like IIS, Apache web server, Tom Cat web server. A web server typically accepts thousands of the concurrent incoming requests for the specific domain, that it hosts.

In case if the server is down for any reason, the websites that are hosted on this server cannot be accessed. So the downtime is a biggest negative thing for the web hosting companies. Many hosting companies have to mention the uptime of their servers for the client’s satisfactions like 99.9 % uptime. You may have seen this percentage on many hosting companies’ websites.

The web servers serves the objects in the form of html documents, plain text, images, sounds, video and some other form of the data. Many of the data types may not be placed in the static form but they are shown on the run time by the software programs, that are installed on the web server and the CGI scripts are the most common form of these programs.

Web servers and the browsers such as internet explorer, Firefox, Netscape, Opera etc communicate with the web server by using the HTTP protocols (Hypertext Transfer Protocol). This is very effective method of requesting the data over the Internet. Web servers are in various shapes and sized and run under different operating systems like Windows, Linux, and Unix etc. They are also range differently in prices and working.

Apache Web Server

The Apache web server is the most popular and most commonly used web server today. Apache web server has many features and good functionality that appeals to the users and that’s major cause of its popularity. On the other end, Microsoft’s IIS still is struggling to complete fully with apache web server. IIS is a very good server on the NT platforms and Apache is compatible with the Linux/Unix platforms.

Another big reason for the worldwide acceptance of the Apache web server is its stability. Many big websites on the Internet has chosen Apache web server for their hosting needs.

Additionally, Apache web server is a relatively fast. If your website contents are static then Apache’s working is very efficient and fast and on the other end, if you are using scripts like CGI scripts or others, it usually slows down the speed of the Apache web server.

A Web server is simply a little piece of the software, it takes the file name sent in the GET command, retrieves that files and send it back to the browser.

Most servers implement some level of security on the serving process. For example login/password accessible page requires the proper login and password from the users to accept that page. Web servers have the database and login information of the entire subscriber and only a subscriber of that typical service will be able to see that page. Additionally, while doing secure transactions the web pages allows encrypted transactions between the browsers and the servers such as on the E-commerce websites and other websites where a transaction through a credit card is required.

Basic Overview How Web Server Works

A web server performs various tasks on the request from the clients. To understand the working of the web server, it is necessary to first understand that what is client and server and what is their relationship with each other. A client is a program that sends request to a server and server responds to the requests of the clients.

This generic definition covers many types of relationships between client and servers like database server & web server etc. Web server have to be connected to the internet because client computers need to access them for various needs like data, files, graphics, video and html documents access.

The client program such as browsers and typically designed for the purpose of communicating with the web servers. A browser itself has different levels of features and security. To start the communication between the client (browser) and the server, a set of rules or agreed upon way is required and that is called a protocol. To access the web pages from the server HTTP protocol is required and for the file sharing access FTP protocol is required. There are a large number of the web protocols.

A web server is configured and designed in such a way that it responds to the thousands of the concurrent incoming requests from the clients for different things like html documents, graphics, images or video etc.

Introduction to Internet Fax Services

Here you will learn internet fax server overview and general introduction to the online faxing methods, how to send a fax and online services. A fax server consists of these things a PC, which is connected to the LAN, Fax server software installed on the PC and a Fax modem or a Fax board. Fax messages can be stored as printable documents, spread sheet, database or graphics. When someone wants to fax the documents, they can print the document to the fax printer then put the recipient information such as name and fax number, select the cover letter, type your message and then send the fax through the faxing software installed on your PC.

Alternatively, you can send the fax to the email messages and can take the fax number from the outlook express contact’s list. Sending fax through PC typically takes less than 30 seconds.

Alternatively, fax server can also be setup to receive the faxes and after receiving the faxes, these can be sent to the printer machine or can be sent to the specific recipient’s email address to notify them that he/she has received a fax.

There are certain advantages of the PC fax server, which I have discussed as follows.

1. The main feature of the Fax server is that it saves your time and cost and you can send the fax in the same way as you send emails and attached the fax to send to the recipients.
2. Invoicing, purchase orders and requested information can be scheduled to be faxed to the intended recipients.
3. Fax server will also retry if the recipient number is busy or if there is any error in the number.
4. You can also save the fax numbers of the frequent users.
5. Fax books also make it easy to send the faxes to the groups of people and at the scheduled times.
6. The faxes that are sent directly through the PC are looks better in terms of the resolution.
7. You can also manage the fax server to redirect the receiving faxes to the appropriate recipient so ensuring the security and timely receiving of the faxes.
8. The administrators can automate many functions of the fax server. A fax server can be configured to automatically send the invoices, purchase orders and the promotional newsletters. Additionally, a fax server can work without papers and reduces the overhead of putting and checking the papers again and again. Fax messages can be stored in your PC.

What is a Internet Fax

Internet fax is a device that uses IP networks to transmit the faxes instead of the PSTN. Internet fax uses e-mails as the medium for sending the faxes. Internet fax services include email to fax, fax to email and PC to fax (sending faxes from your computer). Internet fax is type of service, which enables you to send and receive the faxes in a timely manner without a fax machine. Only an email accounts is required to setup your Internet fax account.

Subscribers have to monthly fees to the internet fax service providers. Internet fax service providers usually works in a way that when a fax is sent to the subscriber’s number, the fax service receives the fax and send it to the recipient’s email address as an attachment.

All you need is to have the registered email address with the internet fax service providers. You have to write the fax content in the body of the email and type the fax number in the “To” field with a @ sign and a internet fax service name e.g 14545668999@efax.com. In the subject field sender can write the name of the recipient.

There is a small tool bar in the system tray for sending and receiving the faxes and it comes after installing the fax software. Upon receiving the email to the Internet fax service providers the automated programs convert the email messages to the fax format and send the fax to the recipient fax number. On the other, hand the recipient receives the fax on their fax machine normally.

The Internet fax services provide very ease and you assigned a fax number, which has to be active 24 hours so that you account can accept the faxes. On the other hand, the working of the regular fax machine is typically depends on your telephone line, which should be free while sending and receiving the fax. Internet fax service also saves your papers and the need of the fax machine.

Internet fax service is very familiar to the sending and receiving the email messages and it also saves the cost and time so many people are likely to use this service.

Another big advantage is given by the Internet service providers is that it offers the toll free numbers to its subscribers in USA and Canada. So the people from USA and Canada can send faxes for free. Most internet fax services costs $10-20 per month. The communication charges are greatly reduced as opposed to the conventional fax machines, which costs a user per page.

Gateway

Here you will get the software and hardware network gateway overview and general introduction, basic configurations, software configuration, bandwidth, firewall overview and routing methods. Gateway is a network point that acts as the entrance point to another network. A gateway can be a hardware or software. 

On the Internet, a node or a stopping point can be a gateway or a host. A router also acts as a gateway. The computers that control and manage traffic and bandwidth within your company’s network or at the ISP are the gateway nodes. In the enterprise network the gateway node acts as a proxy server and a firewall. The gateway is also associated with a router and a switch. 

A network gateway is an internetworking system that joins two networks together and it can be configured in software, hardware or both. Network gateway can operate at any level of OSI layers model. 

CONFIGURING THE GATEWAY

The gateway has two sides: The WAN side connects to your cable DSL modem and LAN side connects to your private network via a hub or switch. The main function of it is to route the traffic from computer to the Internet and back to the computer. A computer with the two NIC cards can act as a gateway. It routes the network traffic between two logically and physically different networks. 

In its configurations, you first configure the public side of the gateway and the IP address, which is assigned to you by your ISP. The public side configurations generally includes, assigning the IP address, DNS server, subnet mask, ISP gateway IP address and host name. Additionally, if your ISP uses PPPoE, you simply have to enable PPPoE in your gateway. 

On the other hand to configure the private side , you have to enable DHCP. By enabling this feature each computer in your network, will automatically pick the settings from the DHCP server that are required for a computer to be a part of the network and communicate. 

SOFTWARE CONFIGURATION

The last step in the configurations, is to configure each PC in such a way that it automatically gets the all the settings from the DHCP server. Make sure that TCP/IP protocol is properly installed in each computer of your network. After configuring each PC in your network perform a reboot.

After rebooting the each PC in your network, you will see a blinking underneath network icon on the right side of the task bar. If everything is done then you can access the internet, share the printer and data in your network. 

The firewall can also be configured with it to put a check on the unauthorized network traffic from the internet to your computer or network.

Introduction to Home Computer Networking-Basic Setup

Here you will get the basic Introduction Home Computer Networking-Basic Setup, wireless access point, lan troubleshooting, lan connectivity, dsl modem, gateway device, vpn and wi-fi. Computer Networks exists for more than 30 years and only recently they have become more popular at home both in forms of wired and wireless networking. Now many computer literate people from all over the world wish to have a computer network at home. There are many advantages and usage of a network, which we have described in the other sections of this website. 

Millions of people have adopted the home network and now they are looking for the more advanced technology in the home networking and that is “wireless home networking”.

We will discuss the various basic and advance aspects of the home networking considering that no prior knowledge of the network technology. We will briefly explain the setup, troubleshooting, installation, network devices used and other aspects of the home networking. 

Today in the age of Information technology, it’s not difficult for someone to have more than one PCat home.

If I apply this situation to you (that you have more than one computer at your home) then most probably you would wish to have access on the data and resources like, hard disk, printer, modem of the other PC and you can even access the broadband Internet like DSL or cable modem and you can also play a multi-player network game. All this is possible by just connecting and configuring the two computers at your home. There are several ways to do the home networking but all it depends on budget, security needs and nature of your work.

Your cable/DSL modem plugs straight into the computer. The computer is exposed to the public Internet (indicated by the color red). There is no connection for more than one computer. You only have one IP address from your ISP. 

If you have a broadband Internet connection at your home like DSL or cable net then you can share your internet connection with more than one PC at your home by installing the network card in each PC and configuring the hub/switch or a router.

If you have two PCs at your home and you want to share your internet connection with the other computer then you can simply share the internet connection by following these steps.

1. Connect two PCs with CAT5 cable and make it a cross over cable.
2. After connecting both the PCs, assign a different IP addresses by going in the properties of the LAN card like 100.100.100.1 and 100.100.100.2 or you can assign any other IP address. (Please note that these IP addresses that you use for your home networking are the private IP addresses and they have nothing to do with the IP address that are used on the internet (public IP addresses).
3. After assigning the IP addresses install software on the computer one, which will be used for sharing the Internet connection and this will be called proxy software (and your computer one will act as a Proxy Server). The more common proxy software is Wingate, Win Proxy and Internet connection sharing (ICS). ICS is by default installed in Windows operating systems and can be configured separately.

Internet access by using a hardware router/gateway/firewall device

In this situation, you have to install a hardware router, which will be act as a gateway. Your router will be connected with the public IP address, which will be assigned to your by your ISP and hub/switch will be attached to the router. All the other PCs in your home or small network will be directly attached to that hub or switch.

How to setup the Gateway Device

Gateway device – There are different gateway devices available from different companies like

dlink.com, linksys.com, netgear.com and Cisco systems. Each device has difference setup configurations but the basic purpose of all these devices is the same. 

The Gateways have a number of common features and functions such as NAT (Network Address Translation) that translate your public IP address into the private IP address on your network, DHCP server, PPP. Before buying any gateway device, make sure gateway device must have all these features.

Some advance gateways have the following features.

• wireless access point
• VPN
• print server
• DMZ (make one PC available to the Internet but still protect it through the firewall
• multi-port
• Content filtering

Most advance gateways comes with integrated hubs or switches and if your gateway don’t have the functionality of a hub/switch then you will have to buy a hub/switch for your home network. Before buying a hub/switch you should consider the two main things 1. it should support dual peed i.e 10mbps and 100mbps and 2. it should have maximum available ports. 

Cat5 cable – For setting up a home network, you will need a several pieces of the CAT5 Ethernet cables. These cables can be used in the different scenarios like for connecting the two PCs (if you have a two computer network) and if you have more than two computers then each computer will be directly connected with the hub/switch or gateway device. The most commonly used cable for computer networking is Cat5 cable. 

Once you have all the required things like cables, hub/switch, LAN cards etc. then install a network card in each PC. You must make sure that each card is properly installed and is not showing any signs of conflict with the other network devices.

How to connect two computers wirelessly

In some recent years, wireless networking solutions have became very popular. There are several wireless technologies exists to support the wireless networking. 

These technologies include Wi-Fi, Bluetooth and infrared. Wi-Fi connections can reach at a greater distance than the other wireless solutions that are mentioned above. Many new PCs and Laptops now have the built-in capability of the Wi-Fi. Wi-Fi can be used with or without network fixture. In the two computers Wi-Fi networking minus a fixture also called ad-hoc Wi-Fi.

Bluetooth technology supports high speed wireless connectivity and communication between the two computers without the need of a network fixture. Bluetooth is commonly used when networking a computer with the consumer’s cell phone or handheld device. Bluetooth works well if both the devices are in the same room or location. While networking among the handheld devices consider the Bluetooth technology solution. 

Infrared networking exists before the Wi-Fi or Bluetooth technologies on the Laptops. Infrared wireless connections only work between two computers and do not require a fixture. Infrared networking is relatively fast so consider using it if your computer supports it and you don’t have the Wi-Fi and Bluetooth features in your computer.

An Overview of Computer Network Topology

Here you will learn network topology introduction, how computers get connected, bus, star, hub, hybrid, mesh, tree topologies and network physical design. In Computer Networking “topology” refers to the layout or design of the connected devices. Network Topologies can be physical or logical. In this section I will illustrate on the different types of the topologies.

Computer network topologies can be categorized in the following categories.

•  bus
•  star
•  ring
•  mesh
•  Tree.

Hybrid networks are the complex networks, which can be built of two or more above mentioned topologies.

Bus Topology

Bus topology uses a common backbone to connect all the network devices in a network in a linear shape. A single cable functions as the shared communication medium for all the devices attached with this cable with an interface connector. The device, which wants to communicate send the broadcast message to all the devices attached with the shared cable but only the intended recipient actually accepts and process that message.

Ethernet bus topologies are easy to install and don’t require much cabling and only a main shared cable is used for network communication. 10Base-2 and 10BaseT are two popular types of the Ethernet cables used in the Bus topology. Also, Bus network works with very limited devices. Performance issues are likely to occur in the Bus topology if more than 12-15 computers are added in a Bus Network. Additionally, if the Backbone cable fails then all network becomes useless and no communication fails among all the computers. Unlike in the Star topology in which if one computer is detached from a network then there is not effect on the other computers in a network.

Ring Topology

In ring Network, every computer or devices has two adjacent neighbors for communication. In a ring network, all the communication messages travel in the same directory whether clockwise or anti clockwise. Any damage of the cable of any cable or device can result in the breakdown of the whole network. Ring topology now has become almost obsolete.

FDDI, SONET or Token Ring Technology can be used to implement Ring Technology. Ring topologies can be found in office, school or small buildings.

Star Topology

In the computer networking world the most commonly used topology in LAN is the star topology. Star topologies can be implemented in home, offices or even in a building. All the computers in the star topologies are connected to central devices like hub, switch or router. The functionality of all these devices is different. I have covered the detail of each networking devices in the separate portion of my website. Computers in a network are usually connected with the hub, switch or router with the Unshielded Twisted Pair (UTP) or Shielded Twisted Pair Cables.

As compared to the bus topology, a star network requires more devices & cables to complete anetwork. The failure of each node or cable in a star network, won’t take down the entire network

as compared to the Bus topology.

However if the central connecting devices such as hub, switch or router fails due to any reason,then ultimately all the network can come down or collapse.

Tree Topology

Tree topologies are comprised of the multiple star topologies on a bus. Tree topologies integrate multiple star topologies together onto a bus. Only the hub devices can connect directly with the tree bus and each Hub functions as a root of a tree of the network devices. This bus/star/hybrid combination supports future expandability of the computer networks, much better than a bus or star.

Mesh Topology

Mesh topology work on the concept of routes. In Mesh topology, message sent to the destination can take any possible shortest, easiest route to reach its destination. In the previous topologies star and bus, messages are usually broadcasted to every computer, especially in bus topology. Similarly in the Ring topology message can travel in only one direction i.e clockwise or anticlockwise. Internet employs the Mesh topology and the message finds its route for its destination. Router works in find the routes for the messages and in reaching them to their destinations.The topology in which every devices connects to every other device is called a full Mesh topology unlike in the partial mesh in which every device is indirectly connected to the other devices.

Summary

Topologies are the important part of the network design theory. A better network can be built if you have the knowledge of these topologies and if you know the difference between each topology. Similarly you should have the knowledge of each network device so that you can properly use them according to your network needs. A misconfigured network can result in a waste of time and energy as well as a lots of troubleshooting methods to resolve the issue. So thebasic understanding of the network topologies and network devices is a must to build a good network.