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How to connect 2 subnets on a W2K3 Server with 2 NICs

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  • How to connect 2 subnets on a W2K3 Server with 2 NICs

    I have a W2K3 SBS with 2 NICs (2 different subnets). The first one is 192.168.50.x and the other one is 192.168.60.x. Both of these subnets have their own routers (Alcatel and Netgear) connecting to different ISPs. W2K3 SBS is also a DHCP server with 2 different scopes (192.168.50.x and 192.168.60.x)..

    Each subnet will serve different groups of users. However, I have a network printer on the 192.168.60.x subnet. How do i configure the other subnet (192.168.50.x) to access this printer? How do I configure both networks to be able to access each other?

  • #2
    Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

    Hi reuters,

    Is it an network printer? As a workaround, have you thought about installing the printer on the SBS server, then sharing it to everyone? If file and print sharing is enabled on the NIC to the subnet that has the user is in then this will work.

    Normally, however, you'd do the following:

    For users to access stuff on a subnet other than their own they will need to have the ability to route. In your example, the user's PC will need to route to the other subnet. Conversely, the printer will need to be able to route back to the user's subnet.

    You need to install the routing and remote access (RRAS) off the Windows Server CD, then do the following:

    (lets say that your server's nics have IPs and
    Set a static route for subnet 192.168.50.x to have the gateway
    Set a static route for subnet 192.168.60.x to have the gateway

    On the dhcp scope add a "classless route" for the 192.168.50.x network as having as the gateway.

    On the dhcp scope add a "classless route" for the 192.168.60.x network as having as the gateway.

    You will need to release and then renew your dhcp clients for the new setting to take affect.

    To check that the routing works go to a 192.168.50.x PC and, from the command prompt, type "tracert".

    If that works type "tracert 192.168.60.?" where ? is an IP to another PC besides the server.

    Then do the reverse from a PC in subnet 192.168.60.x

    If the printer IS an IP printer you will have to check if it knows how to route to another network. If it is statically assigned, just set the default gateway to

    I'm intrigued as to how you are getting on with having 2 Internet routers and a server with 2 NICs- have you set a different default gateway on both NICs?

    Let me know how you get on,

    Hope this helps,



    • #3
      Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

      Hi gibjon, thank you for your help and reply. I will give it a try with your solution to see if it solves the problem.

      I just took over this network not long ago and that is why I am also puzzled on the setup. Both NICs are using the router's IP as their gateway ( and If I am going to change the gateway addresses on the 2 NICs, i think it might affect the Internet access am I right?

      The printer is configured for IP printing and it is having an IP address of

      Anyway do I need to have 2 separate network switches to serve the 2 subnets? I am using 1 network switch to connect all workstations as one of the old switch is spoilt.


      • #4
        Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

        Hi reuters,

        You're welcome.

        Practically speaking, for a dhcp server to serve 2 different scopes on 2 different subnets you need to have each NIC on the server on a separate switch (or more accurately speaking on a separate collision domain).

        You can separate a single physical switch to act as 2 independant ones IF your switch supports VLAN. If your switch says "managed" then the answer is probably yes- let me know. If you don't have this facility, 3com do some good 24 port 10/100 managed switches for about $500-ish. They also have a few extra gigabit ports for connecting your servers.

        Going back to what I was asking you about having a different default gateway on each NIC of the server:

        What happens when you pull the plug on the 1st NIC? Does the server automatically use the 2nd NIC's gateway for its Internet connection? I've never tried this configuration before but have heard people warn others away from it. Just wondering if it actually works...

        Get back to me when you can (I'll be checking the forums this weekend),


        PS- with a name like reuters, do you work for a financial trading firm? Just curious because I share an office with some traders.


        • #5
          Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

          Yah.. i think i will be using 2 unmanaged switches to separate the 2 subnets then.. it will be much more cheaper than using 1 managed switch..

          I think I have tried to disconnect one of the NIC and the server is actually able to access the Internet through the other NIC's gateway.. but i guess i need to get another new network switch to separate the 2 subnets first to see if it works.. I have heard of others using the subnet mask other than the class C one to make 2 subnets see each other.. But i think we need to setup the RRAS as what you have suggested to do the routing though..

          I will give it a try later this week after getting the additional network switch..

          PS: nah.. Im not working in any trading firms.. its just one of my favourite nicks that i've been using very long..


          • #6
            Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

            Hi Reuters,

            So long as both IP networks are in private address ranges, it won't matter whether one is a class c and one is another (eg- a or b). I've found a list in case you need it:

            10.x.x.x is Class A which has the subnet
            This gives you one network with a massive amount of IP addresses (about 16 million) for hosts within the network. You can reduce the amount to something more sensible by adjusting the subnet to one usually used with a class b or c network.

            172.16.x.x - 172.31.x.x Class B which has
            This gives you a choice of 16 different networks with about 65,000 hosts. To reduce this amount to a total of 253 useable IPs, just use the subnet instead.

            192.168.x.x Class C which has a subnet of
            This gives you over 250 different networks to choose from...

            I reacently troubleshooted a client's network that the previous engineer screwed up- he chose 192.10.0.x as a 'private' range- everything worked fine except that the 192.10.0.x range exists on the Internet, somewhere in Italy. The downside was that they couldn't access certain websites- they had clients in Italy!

            You can use any mixture of class a,b and c networks.
            Its good that you've used 192.168.50.x and 192.168.60.x because should you need to connect to another companies private network later on, the chances are you won't need to change anything on your LAN to suit their's. Its (ipsec) VPNs that generally cause this issue and, IMHO, you're best avoiding them anyway in this day and age...




            • #7
              Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

              Gibjohn you used bad examples.... let me explain what I mean.

              Classes of IP address really only make an awful lot of sense on the internet's "live" address space. In private networks, it's almost universal that an "off-class" subnet mask is in use which renders the class obsolete.

              ALL of the IP ranges you quote are NOT ROUTED on the internet; in fact their packets are dropped like hot potatoes by any internet router. So - technically yes a 10.x.x.x address WOULD BE a "Class A" address were it on the Internet - however it would not talk to anything as the first network device would drop the packet. 10.x.x.x, 172.(16-31).x.x, and 192.168.x.x are effectively classless because they can ONLY be used on a private network which will often have an off-class subnet mask.

              You'd have been better quoting the class boundaries to be honest...


              For my own and your protection, I do not provide support by private message under any circumstances. All such messages will be deleted and ignored.

              Anything you say will be misquoted and used against you


              • #8
                Re: How to connect 2 subnets on a W2K3 Server with 2 NICs


                I don't think I would have been better off explaining the class boundaries.

                I was responding to the context of what Reuters was mentioning. I had intentionally listed "IP ranges that are NOT ROUTED on the internet"- did you read his last post???

                Referring to private, "not routable on the internet" address ranges as class c, b or whatever is perfectly acceptable. I had also elaborated on what you refer to as "classless", eg- using (subnet instead of /8 (subnet so you can have a smaller number of hosts.

                //Comment removed by Mod//

                Lots of love,

                Last edited by ahinson; 31st December 2007, 17:54.


                • #9
                  Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

                  Time to cool it here, I think.

                  Gibjon, if you check out Stonelaughter's history here, you will see he has given much very good advice to many members. He did not mean to be offensive in his post and I am sorry if you have taken it that way.

                  I have reported the second copy of your post (identical, 30 mins apart) to the forum moderators / admin. I assume this was a "back button malfunction" as the forum rules are very clear about multiple posting.

                  Now, lets enjoy the new year
                  Tom Jones
                  MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
                  PhD, MSc, FIAP, MIITT
                  IT Trainer / Consultant
                  Ossian Ltd

                  ** Remember to give credit where credit is due and leave reputation points where appropriate **


                  • #10
                    Re: How to connect 2 subnets on a W2K3 Server with 2 NICs


                    There's no need to insult others, regardless of how much you dislike the contribution(s) of another forum member. Continuing down this path will only end up in your being banned from the forum.

                    Consider yourself warned.

                    ** Remember to give credit where credit is due and leave reputation points sigpic where appropriate **


                    • #11
                      Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

                      Hi guys,

                      Fair enough- it won't happen again. I'm very sorry, Stoneslaughter.

                      My best wishes for the new year to all,




                      • #12
                        Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

                        Hi gibjon/stonelaughter,

                        sorry for causing the disputes.. i know everyone here is just trying to help.. so pls do not be offended!

                        anyway, the 2 subnets are now working, thanks to gibjon's earlier suggestion on setting up static routes etc.. i have also separated the 2 subnets with 2 individual network switches..

                        the 192.168.50.x subnet is able to ping to (NIC A) and the 192.168.60.x subnet is able to ping to (NIC B)..

                        the 192.168.50.x subnet is also able to ping and print to the ip printer

                        so now both subnets are using their own individual router to access the Internet (i.e. and

                        Really appreciated your help.. Thanks guys!


                        • #13
                          Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

                          I got the setup of 2 nics, i do not need 2 network to see each of them. Basically i have one NIC to browse Internet, one NIC for local network. The WAN nic is connect directly from my server to the ISP router (separate to my LAN router and do not go through any local switch). I was able to connect and use my local software. But there are sometime that the local connection drop all connection. I have to disable the WAN Nic so that the LAN NIC can work and enable the WAN again. I can do it manually or using script however if it does it during the day and there are some transactions from client computer to the server we will lost our data. Do you have any suggestion on it. Thank you


                          • #14
                            Re: How to connect 2 subnets on a W2K3 Server with 2 NICs

                            Wow, all these posts make my head hurt. Here's a question: If all clients were originally connected to the same switch, then why use 2 separate internet connections, routers, and subnets? Do you have some need to send certain clients traffic through a certain ISP?

                            Second, the comment about 2 switches creating 2 separate collision domains is incorrect. 2 separate switches will create 2 separate broadcast domains. Each port on a switch is it's own collision domain.

                            Third, you could probably accomplish your goals by assigning a second ip address to each router for the other network and adding a route on one router to the other one. This would effectively mean that clientA on subnetA sends traffic destined for subnetB to routerA, which then sends the traffic through the switch to routerB, which sends it to clientB. The routers become "routers on a stick" which is the method you would use when setting up VLAN's on a layer 2 switch (except you would use one router).
                            Last edited by joeqwerty; 4th January 2008, 05:58.