two sbs 2003 the same network subnet

Posted on 2008-11-16
Last Modified: 2012-05-05
I would like to know if I can have 2 sbs 2003 severs on the same network subnet.  They will be independent running their own AD, meaning they are not in the same domain or have any trusts.  I'm getting mixed information that 2 SBS servers an not even be in the same network subnet.  Is this true?  I have a client that as an sbs 2003 now and all the computers are joined to it.  While they want to introduce another sbs 2003 as an exchange server/fileserver separate from their current one , but will be on the same network subnet of 192.168.1.x

If a user needs to connect to that fileserver (new sbs) they will just map to the share.

Is this fine?
Question by:digi_net

    Expert Comment

    I have setup 2 SBS 2003 servers on one network subnet with no problems (it was two separate companies that needed to access each others data)  but they have to be two different domains.  Though it is possible it is not recommended.  You wont be able to attached one computer to both domains - but if you manually setup the exactly same user accounts on both servers  the workstations should be able to access them.

    As soon as you start to use more than one server for the same network you will have a much easier time managing it if you use standard edition servers.  You could use the SBS 2003 transition pack to convert your current SBS server to standard edition and then add in another 2003 standard server.
    LVL 3

    Expert Comment

    i have tried this and eventually one or other did complain and shutdown system services and everyone connected was disconnected at random, new connections were blocked.

    i now run the secondary domain behind an internal router to seperated them but this negates the ability to have them on the same logical ip subnet.

    two sbs servers cannot co-exist on the same physical subnet except for the limited migration period after which the servers will cease to function. (they will "fight" each other)

    the idea of using a cheap sbs platform as a secondary server is tempting but is fraught with issues in this situation. currently the site i have 2 sbs servers is for two logical groups working totally independantly of each other.

    Author Comment

    I keep reading (even on this site) that, 2 SBS can not exist on the same network because of a few days it will shut itself down?  
    LVL 3

    Expert Comment

    correct, there is a limit in days for concurrency from the time they see each other. this only applies to migration. two servers on the same network except during migration will cause one to shutdown network services, (like dhcp does on detecting another dhcp server)

    Author Comment

    If I configure the 2 sbs server to  be a site to site vpn (192.168.1.x and 192.168.2.x) so users can see both servers and all the ports open, this would also cause the server to shutdown correct because it will still see each other?
    LVL 3

    Accepted Solution

    if you put a small router inplace and have the second sbs server plugged into the router in that configuration then yes it would work ok. then the two networks are seperated by a router and therfor independant.

    lan 1 192.168.1.x
    gateway router 1 on
    static route 192.168.2.x to

    second router on lan 1 at
    lan 2 on 192.168.2.x
    router 2 internal network of 192.168.2.x
    dmz all traffic to 192.168.2.xx (second sbs server ip)

    one network is then "inside" the other but visible via ip address, to sbs it is then a completely different network as it passes through a router and therefor not "on the same network"

    the router is the key to the operation

    Author Comment

    Can I do this?

    They are actually in two separate buildings and with their own dsl lines, they are planning to run a cable from one building to the second.  If I just do this, would this work?

    gateway is which is their firewall.

    The firewall has a site to site vpn to 192.168.2.x which is the lan on the other building.

    Since they are on a vpn and all ports are open, even if the are on separate subnet... the firewall is connecting them. Does that mean that the sbs server will attempt to shut each other down?

    Author Comment

    So if I get them to get a windows 2003 standard. It should then be no problem putting in a new domain controller on the same network subnet where the current sbs server is at?

    The windows 2003 standard would be configured as a separate domain but within the same network segment.

    LVL 3

    Expert Comment

    re cable, and two networks then yes replacing the dsl at one site with a physical link to the other and using a router they would work ok.

    again, re vpn, since it is routed the two servers are NOT on the same network and therefor will not impact on each other.

    re 2003 std server.
    if you are going for a std server it will not impact the original sbs server at all, but why would you have it in a seperate domain when as a std server it could join the sbs domain correctly?

    net result,
    sbs + std server would not cause any problem.
    sbs + sbs server will


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