NAT&IIS

SHARING INTERNET

If you have one Internet connection in your network, you can share this connection to all the computers in the network. To share Internet, we can use the following technologies/services:

1. ICS (Internet Connection Sharing)

2. NAT (Network Address Translation)

3. Proxy Server (using software like Win proxy)

ICS

ICS is a service, available in win XP professional, 2000/2003 server and 2000 professional, used to share Internet in small networks. Internet can be shared only in 254 computers using this service.



PRACTICAL OF ICS

1. Go to Win XP Professional computers and install two LAN cards as shown in the diagram above.
2. Right-click on ‘My Network Places’ > properties.
3. Right-click on the LAN card which is connected to the Internet and select properties.
4. Click Advanced > Internet Connection Sharing.
5. Select ‘Allow other network users…………..’.
6. Click O.K. and Click Yes & O.K.
7. The ip of the LAN card connected to your network becomes 192.168.0.1.
8. A proxy or baby DHCP server is installed which gives ip addresses to the client PCs in the range:
192.168.0.2 – 192.168.0.254
Subnet Mask is 255.255.255.0.
9. Go to the client PCs and open TCP/IP properties:
Select ‘Obtain an ip address automatically’ & also
Select ‘Obtain a DNS server address automatically’.
10. Now Internet will be available on all the PCs in the network.

NAT

NAT is a service, available in Win 2000/2003 server, used to share Internet in large networks. Internet can be shared almost in limitless computers using this service.
NAT translates public address into private address and vice-versa, and hence the name NAT.NAT maps all the private addresses of computers present in your private network to a single public address which is being used to access Internet.



ICS NAT
It can be used to share Internet only in small networks. It can be used to share Internet even in large networks.
Internet can be shared only in 254 computers. Internet can be shared virtually in limitless computers.
DNS and DHCP services cannot be configured.
DNS and DHCP services can be configured and any private address range can be used in the private network.
It is available both in client and server operating systems. It is available only in server operating systems.



PRACTICAL OF NAT

1. Go to a 2003 server computer and install two LAN cards as shown in the diagram above.
2. One LAN card will be connected to Internet and the other to the private network.
3. Now open > programs > administrative tools > Routing and Remote Access.
4. Right-click on computer-name and select ‘Configure and enable……….’.
5. Click Next and select Network Address translation > next.
6. Select the LAN card connected to the Internet and click next.
7. Select ‘Enable basic name and address services’.
8. Click next > next > finish.
9. Now the server is a NAT server.
10. Go to the client PCs and open TCP/IP properties:
Select ‘Obtain an ip address automatically’ & also
Select ‘Obtain a DNS server address automatically’
11. Now Internet will be available on all the PCs in the network.