How To Enable NAT in Windows 2003 Server

I’m writing this tutorial on request of a valuable regular reader of Technodigits.
Situation: I am an administrator of a small company with 20 computers. I’m getting my internet services through a DSL connection. I’m using Microsoft technologies; hence, my server is Windows 2003 Server. I want to distribute internet to all the computers through the main server.
Solution: You can use Windows Routing and Remote Access tool for this situation. Follow the following steps to provide internet facilities to every computer using your Windows 2003 Server.
1- Firstly, you will need two IP addresses, one for the DSL modem interface and the other for the local LAN interface. Either you can install two NICs (LAN Cards) or alternatively you can assign two IP addresses to your existing NIC. One IP address is for the LAN and the other is for connecting to the internet. Please see my post about assigning two IP addresses to one LAN Card here.
2- In your Windows 2003 Server, go to Start –> All Programs –> Administrative Tools –> Routing and Remote Access

3- Right Click the server in the left hand pane and select “Configure and Enable Routing and Remote Access”

4- Routing and Remote Access Wizard will appear, click Next.
5- Select Network Address Translation (NAT) and then click Next.
6- Select the interface that connects you to the internet and click Next.

7- Click Finish.
This will enable NAT on your server. Now configure the network settings of your client computer and give the default gateway of your server LAN interface. Or if you have setup a DHCP server in your network, configure the DHCP server accordingly.
This is all that is required to provide internet facility to your entire network through one server. Your feedback about your experiences on this topic will be highly appreciated.





25 responses to “How To Enable NAT in Windows 2003 Server”

  1. Iftikhar Qamar

    Hello Sanix and Abdullah,
    I am a programmer by profession, I am trying to host a website on my authentication server because of some reasons(I know its wrong but this is the scenario). I am planning to use 2nd IP for the same NIC but what areas of a server are effected when we assign it multiple IP’s. So that i can figure out, what i am going to toy with.
    Looking forward to a prompt response.

  2. ammaro

    thx a lot for this useful Tuto may god bless you

  3. sal

    reallr awsom!!!!!!!!!!

  4. sudhakar

    I restricted hotmail site but how to connect site .
    in windows 2003

  5. Sanix

    sudhakar, I couldn’t understand your problem .. how did you restrict your hotmail site? and how do you want to connect to the site again? Please tell me your network in a lil detail so that we can figure out a solution..

  6. Pradeep Kumar

    I need help to configure NAT in windows 2003 please give me the step how i have done the same.
    My ISP provide me one WAN IP(with that i am able to access internet) and Sixteen LAN (Publec IP) and they ask me to configure this in your router yaa firewall (that have NAT ing facility)
    Please give me the solution how i can use my windows 2003 server and a router and with that i can able to use my all Sixteen IP as a public IP i want to configure those publice IP in my (FTP, Hosting , And etc device,
    Waiting your Positive reply
    Pradeep Kumar

    1. Sanix

      Pradeep, just configure your router with one of the Static IPs which your ISP has assigned you. And the second one you assign to your Windows Server 2003 machine. Now you should have two IPs in your Windows 2003 Server i.e, your public IP given by the ISP and the internal LAN IP. To see how to assign two IPs, please see the following article.
      Assigning two IP addresses to one ethernet card in Windows
      And then follow this article to create a NAT on Windows 2003.
      If you have any problem, feel free to visit us again 🙂

  7. mehedy

    if i do not want to give all my lan pc’s the internet facility through my server though they are connected with my server..
    and how can i limit the bandwidth ??

    1. Sanix

      mehedy, you can do so by removing the default gateway address from their computers. This is the simplest of ways.

  8. Mehedy Mizan

    and what are the hard way’s. any tutorials ? i do it with CCproxy. but i want it to do without proxy software. all the ccproxy options. any tutorial on that ?

  9. Guitar Amp Tubes

    Good to be visiting your blog again, it may be months for me. Nicely this article that i’ve been waited for so long. I need this article to complete my assignment in the college, and it has exact same topic with your article. Thanks, excellent write about.

  10. A.N.Parthepan

    How to configure NAT in my organisation win dynamic public IP
    please tell
    Thanks in advance

  11. Sanix

    If you are using a router for your internet, then you can easily configure NAT using the method given in this article.

  12. Flavah Dawg

    I want to give internet connection to several computers on my network running Win Serv 03. I’ve install two NIC and my Win NOS is running DHCP, DNS, etc. The int NIC that is connected to the internet should have its own IP add plus the IP of the ISP modem has the gateway IP, and the Net NIC that connects the client to the network have the int NIC IP has it gateway IP or what? Please resolve this confusion ASAP? Thanks

  13. Sanix

    @Flavah Dawg
    You don’t need to put the default gateway in the net NIC. Just leave it blank and everything should work fine.

  14. narasimha

    I have configured NAT. I could able to browse internet from the Win 2003 Domain, but I couldn’t able to browse internet from the clients. I can able to ping the win 2003 private and public IP Addresses.
    Can you please give me solution for the above problem

  15. czach

    sir i have already already a server 2003 running with 12clients and dsl connection.what will i do to balance the bandwith w/ each client.i use all client for online gamings.need help……thanks in advance

    1. Sanix

      You have to use Microsoft ISA server for the purpose of balancing the network usage among users.

  16. narasimha

    I have configured NAT. I could able to browse internet from the Win 2003 Domain, but I couldn’t able to browse internet from the clients. I can able to ping the win 2003 private and public IP Addresses.
    Can anyone please give me solution for the above problem

  17. Flavah Dawg

    Thanx 4 your previous advice regarding NAT config.. but i was wondering, is it possible for a server that runs NAT, be able to connect client through VPN setup as well or its has 2 be either 1 or the other? And if so how do you go about setting up both, well the VPN aspect of it…. thanx in advance

  18. Flavah Dawg

    Please discard my previous request posted on your site… This it what i really want to know. Why do i have to manually config the clients IPv4 on the network to the appropriate/available ip addresses of the DHCP scope b4 they can get internet access. Bare in mind i’ve install 2 NIC adapter n my DHCP scope is fr. – No comp can access the internet through wireless connection unless i manually config their IPv4 to an available ip address within the scope… Plz help, its hectic and time consuming… Thanx in advance

  19. Sanix

    @Flavah Dawg
    You have mentioned that only wireless users are not automatically configured. You must configure the Wireless Access Point so that the users connected wirelessly should be pointed to the correct DHCP server for obtaining the network configuration.

  20. czach

    sir can you pls send me a tutorial on installing a microsoft isa server and what is the compatible version of ISA server for windows server 2003 enterprise edition sp2.I installed ISA 2004 and it messed up my server i lost my connection in the internet

  21. Ali

    Thanks alot for the beautiful stuff

  22. drakonli

    Hello. I need a problem help. I have 2 NICs, windows server 2003, nat enabled and 4 comps connected to server. Internet connection shares ONLY when i configure ips manually. Basically, I have the same problem as Flavah, but not only wireless. My client computers are all lan connected through a switch.