SBS2003 dual NIC to SBS2003 single NIC Connection


We are preparing to migrate our server running SBS2003 to SBS2011, in doing so we have to reconfigure the network from a dual NIC configuration to a single NIC configuration. The way it is now, the connection comes in like this:

Internet - Cable modem - router - server - LAN switch

The new configuration is:

Internet - Cable modem - router - LAN switch

We also use 90.0.0.* as our internal IP range and it looks like we will not be able to use that in the new OS, so will be switching to 192.168 during this process. I am not very experienced in networking so I want to make sure that I am doing this right. Also if it helps any, the server is virtualized on VMWare ESXI 5.0.

Please confirm the process for me:

1. Disconnect network cable between router-server from server, disable this NIC in Network Connections on the server.

2. Connect network cable between router-switch.

3. Disable DHCP on the router.

4. Run Configure Email and Internet Connection Wizard. I haven't ran this in years so I don't remember what this entails, I assume this is where I reassign the static IP of the server and other settings, is this also the time I would change the internal IP range to 192.168?

5. Reboot server.

6. For our systems that use DHCP, do I need to go to each one and ipconfig /release and then ipconfig /renew?

7. For systems using static IP, I assume it should be simple to just change their IP to the new range and it will work OK?

8. All computers on the network would use the server IP as their primary DNS server? The gateway would be the router IP and not the server IP?

9. With this new configuration, if I do a server reboot or bring the server down for whatever reason, would the internet connection still be available and 100% functional to computers in the office?

Thank you for any help/clarification.
wxitguyDirector of ITAsked:
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Jeffrey Kane - TechSoEasyConnect With a Mentor Principal ConsultantCommented:
First of all, the process to get this done is clearly documented:

Please make sure you review and understand the documentation.

Before doing anything, decide on the IP Subnet you are going to use (let's say it will be 192.168.16.x).  You must then set the LAN IP of your new router to

You cannot change the IP of your server with the CEICW.  Instead, you need to run the Change Server IP address wizard which you'll find right next to the CEICW.  Run that first and change the server IP to

Then you can run the CEICW.

I would highly suggest that you do not manually assign IP addresses, but rather use DHCP reservations for devices that you wish to have a static IP for.  This keeps all IP management in a centralized place.

With the new configuration, rebooting the server or having it be down has nothing at all to do with the Internet connection because your gateway is the router.   These settings will get populated to the SBS's DHCP Scope automatically when you run the CEICW.

If the server is unavailable, you will have the same problem that has always existed in a single server environment with a single DNS Server -- and that is that DNS will become unavailable.  Which means that any NEW request made by a user while the server is unavailable will not resolve properly (previously visited sites would probably be cached in their workstation's DNS).

If you are truly concerned about this issue, then you need to be concerned about 10 or 20 far more important issues that could occur when you run a single server environment.  DNS is not that big a deal compared to the others.  Such as loss of access to important company data, loss of access to a LOB app (such as QuickBooks), etc.

It is for those issues that you need to have a solid disaster recovery solution -- which can get your server back up and running in reasonable time.

Good Luck!

wxitguyDirector of ITAuthor Commented:
Thank you for the information.

Over the years we have reduced the responsibility of the SBS2003 system to the point that pretty much all it is doing now is Active Directory, DNS, DHCP, Exchange, and manages the internet connection for the office.  So if we can get the internet working correctly when the server is offline it would be a big help for our operations team.

I am using DHCP reservations currently, my understanding of how reservations work is that on the system that needs a static IP, you set it manually, then on the server you assign a reservation to it so the system's IP will not be automatically assigned by the DHCP server to another system. So I am using reservations but am I not using them correctly?

Is there a way to configure the computers to use the router as secondary DNS server when the primary DNS (SBS) is down? Our router does include DNS server capability.
Jeffrey Kane - TechSoEasyConnect With a Mentor Principal ConsultantCommented:
That is not how DHCP Reservations work.  You do not set it on the machine manually.  When you configure the reservation on the server, you assign the client's MAC address to an IP which then ensures the reserved IP is assigned when the client makes the DHCP request.

If you say you've reduced the responsibility of your SBS, are you saying you have another server in the domain?  If so, then you can make this other server handle secondary DNS.  That would be much more preferable than having a non-domain based DNS server.  

Adding a second DNS server to your DHCP scope is fairly easy -- just modify the scope options.

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