Internet Sharing

Internet sharing is the ability to make sharing / sharing an internet connection. With just a communication channel (eg phone) multiple computers can be used together as well as to connect to the internet. Of course the cost of communications (in this case the phone) and Internet access can be shared to all computer workstations so that the cost is leih priced.Overall outline, internet sharing components are:

1. Gateway
   Gateway computer (gateway) is used as a liaison between the network / LAN and internet. Typically use a proxy software (eg WinGate) with facilities connected to the Internet (in this case using a dial-up phone). We simply use a known IP address / teregristrasi on the Internet from the ISP where we signed up.
2. Network/LAN consisting of workstations
   Consists of computers that can connect to the internet through the gateway together. These computers use a private IP (IP that is not known by the internet / network outside) eg using IP 10.xxx
3. Internet ConnectionThe method used to connect to the internet (in this case using a dial-up phone).
   
   Three of which are workstations, each using a private IP. Meanwhile, in addition to having a private IP gateway also has an IP address that is listed on the Internet come from his ISP.
• The introduction of WinGate
  Wingate is a program that can be used to perform Internet sharing in Windows operating systems as well as having many other facilities include:
• Proxy
  Some internet proxy services that are important:
1. service >> Function >> Port Number (general) 
2. Web (www) >> accessing the web >> Port 80/8080 
3. FTP (File Transfer Protocol) >> Taking file >> Port 21 
4. Telnet >> Log in to another computer >> Port 23 
5. RealAudio >> Hear audio >> Port 1090 
6. SOCKS >> Interactive servicing (eg ICQ) >> Port 1080
• Implementation of the policy / policy
  We can set some policies that can be applied on the client computer. The policy is primarily a matter of the use of proxy services that we provide, include:
  
  
1. The use of a password on the client computer to use a proxy service
2.  Restrictions on certain user 
3. Restrictions on certain services
   
   
• Caching
  With this facility, we can save web pages are accessible from the Internet. If there are multiple users accessing client computers the same web page, then WinGate will only take one page. Furthermore, other users will acquire the web page of cache stored by WinGate. Caching can save bandwidth and speed up the Internet to the calling web page.
  
  
• Dialer
  WinGate has the ability to dial into the Internet and backup connection to the Internet if the connection to the ISP fails.
  
  Besides those mentioned above, there are many other facilities owned by WinGate. Please to read the manual / HELP.
  
  
• Internet Sharing On LinuxBroadly speaking, Internet sharing on Linux include:IP Masquerade (masquerade = disguise)So what happens here is the use of IP gateway (IP Internet) by computers on the network (workstation) simultaneously, changing quickly.

1.      IP Forwarding
Functions performed here is forwarding requests to the workstations outside the network (eg the Internet)
To enable Internet sharing on Linux, there are several things you should do:

§  OR kernel configuration module configuration
By default, Redhat not support internet facility sharing. To that can be done in two ways, namely OR recompiling the kernel to load modules. Load module can be done by executing some commands `modprobe`. While compiling the kernel is done by activating the IP Masquaerade facilities.

§  Enabling IP forwarding option (on the /etc/sysctl.conf file)

§  Using applications for IP forwarding (eg: ipchains)

This application is used to perform IP forwarding in order to bridge the network / LAN us with internet.