A gateway is a computer or a physical device that is capable of routing the data between different networks. If the internet is working in another network and you want to have the access of that network you need a device which is able to connect both the networks and that device is known as a Router or gateway.
You need a gateway or a router to have access to the other network. A computer in your office or home which is directly connected with the internet is provided with the default gateway by the internet service providers.
The gateway provided by the ISP is not the part of your home or office network. In order to give access to the other computers in your home or office network, the computer that is directly connected with the ISP acts as a gateway for the other computers in your network. You have to configure it so that it can send and receive the requests from internet for the other computers. For a computer to act as a gateway you only need a Cable or DSL router. The hardware routers are setup as default gateway so that require minimum setup configurations and many default gateways have built in firewall features in them.
How to Setup Client Computers
Before any configurations, you should configure the client computers so that they can access the internet. Assume that the client computers are not directly connected with the gateway at this time. You should make a setup in this way that all the client computers are setup to get the information from the gateway and for this purpose the network adaptor of every computer in your network must be setup to receive the IP address automatically such as Start > Control Panel > Network and Internet connections and Network settings. Now click the connections and hit properties and then highlight the TCP/IP and press the properties tab. Now select the following two options.
1. Get the IP address automatically
2. Obtain DNS server automatically
How to Configure Router Wan Options
You simply set the router to get the IP address automatically if you have a cable internet connection and on the other hand if you have a DSL connection you must go to the PPPOE settings and provide your username and password provided to you by your ISP so the router an dial it. After that for the verification of the connection go to the status screen and check the statistics. Your router must be setup to provide the IP addresses to the PCS in your network by using a method known as DHCP.
Out of the box, your router is set up to distribute IP addresses to the computers in your network, using a method called DHCP (Dynamic Host Configuration Protocol).
There are several other methods to share the internet with the other computers in your network and we discuss few of the methods one by one.
Sharing Internet by Proxy server
A proxy server is software application and when it is installed on any computer, it acts as a proxy server computer. The main function of the proxy server is to take the IP address from the ISP and route the data to and from the internet through it. There are several good proxy server software applications in the market such as Wingate, Winproxy, Browsegate, Microsoft ISA and many others. A proxy server shares the same IP address among the other computers of the network and sends request from the same IP address to the internet. There are no monthly costs of a proxy server once it is purchased and it can also be expanded to many computers as they can be handled easily.
There are many management features in a proxy server application such as it makes a complete log of the activities of all the users of the network as well as computers. Secondly, access to the internet can be restricted to different computers with different access options and different level of usages. A computer that is running the proxy software application should be running all the time to share the internet access with the other computers in the network. Each client computer is setup to install/configure the internet application and also may requires installing the client software of the proxy server. Wingate and Winproxy are the widely used proxy server software applications.
Internet Access by NAT program
NAT or network address translation are the software applications that are used to share the internet connection by using one IP address to allow multiple computers to access the internet. If you are using NAT to share the internet connection then there is no need configure the internet applications on the client computers. NAT is ideal if you use a Laptop and want to make it as a sharing client computer. There is no monthly cost for the NAT and it is very easy to setup the NAT in Win98, WinNT and Mac operating systems. The computer that is running the NAT application must be running so that the client computer can access the internet through it. The NAT may not support many internet applications and it can be time consuming to work on the access management features of a NAT application.
Multiple IP addresses from the ISP
An IP address is a unique identifier of every computer on the internet. The geographical location of anyone can be determined by the IP address. There is another option of accessing the internet for your client computers and that is you have to purchase a number of the IP addresses from your ISP. This method is less expensive as compared to buying a separate cable modem for each computer in your network. This method is easy to setup and you can find good support from your ISP in the setup and configurations. This method works with every operating system that supports TCP/IP and it does not require the multiple NICs in your PC. All the computers that are using different IP addresses must be securely configured so that they cannot be hacked. All the computers who use this option, operates separately from the other computers in the same network.
Sharing Connection with Linux
Linux is a free version of Unix and is available for both the Intel and Motorola operating systems. It can be configured to allow you to access your cable modem connection. Connection sharing by this type is free and very flexible and it can also be run on the slow old computers. It usually requires a dedicated computer to setup and technically it is some difficult for the non technical persons.
Internet Access with Hardware Routers/Firewalls
There is another method of sharing the internet connection with your network computers and that is to buy a network router or firewall. This option is suitable with a larger number of the computers. This solution provides best results as compared to the software and it doesn’t require any dedicated computer. It only requires a NIC in each computer of your network. It also provides firewall protections and very reliable and secure internet connection. The disadvantage of this method is the higher cost and configurations which are not easy for a new user and only a technical personal can configure it.
I have made a list of the free proxy software applications. If you own a small network of 5-100 computers then Winproxy and Wingate are the best options. If you own a big network like more than 1000 computers then Microsoft ISA is a best option. There are a number of other proxy server software applications such as MS Proxy, AnalogX Proxy, Browsegate, EasyProxy, Internet Gate, NetProxy, Proxy+ and a large number of the other programs.