How many times have you found yourself restoring a server which happens to be the DHCP server, and the leases start expiring? Suddenly, it goes from one server being down, to the entire network being down.

I find that when fixing problems with servers during business hours, the users will often be quite content to leave me be, as long as they can surf the web while I work. Sometimes they cannot do this becase the server is also the DNS server.

It’s not worth the time to set up a temporary DHCP server, right?

Wrong.

There is an open source project called Dual DHCP DNS Server. It’s free, it’s powerful, and it is very quick and easy to set up. Assign a static IP address to any workstation, download and install this, adjust a few lines in the INI file, and you’re off and running. the installation takes only a few seconds. At the end, without a reboot, it (optionally) starts the service.

You just need to edit the DualServer.ini file, and edit a few lines. The most important ones for a simple setup are:

[DHCP-RANGE]
DHCP_Range=192.168.2.100-192.168.2.199
Subnet_Mask=255.255.255.0
DNS_Server=4.2.2.2
Router=192.168.2.1
Lease_Time=1000

Override the default settings and adjust them for your network, (re)start the service, and you’re good to go.

Of course there are plenty of options in there, and you can get as complex as you want with this utility – but if you’re like me, you’d rather do that with a fancy GUI DHCP server built into Windows. For a free quick-start simple DHCP server though, this is the ticket.

Tags: dhcp, free

In SBS2003, if a DHCP server is detected, it simply does not install/configure DHCP. No worries, we can do that later.

In SBS2008, when you run the “CTIW” (Connect To the Internet Wizard), and it finds a DHCP server, it refuses to go forward until you have disabled it on whatever is handing out addresses.

You get three buttons: Manage Router, Postpone, and Continue.

If you click Manage Router, it brings up a web browser with the IP address of the DHCP server, so that you can log into it and turn DHCP off (it assumes a web-based management interface).
If you click Continue, it checks again and brings you back to this screen if you have not disabled DHCP.
If you click Postpone, it brings up an error page telling you that the Internet connection is incomplete.

So SBS2008 wants very badly to be the king of its own little DHCP world.

Of course, the way around this is to temporarily disable DHCP on your other device, run the wizard, disable it on SBS2008, and re-enable it on your device.

If the DHCP Server it finds is your old SBS2003 server during a migration, then here is what you should do:
1. On the SBS2003 server, run this at a command prompt:
netsh dhcp server export c:\dhcp.data 192.168.0.0  (substitute your internal network subnet)
This saves your DHCP database to a file o the root of C on your old SBS server.
2. Copy that file to C:\ on your SBS2008 server.
3. Stop and disable DHCP on your old SBS server.
4. On the SBS2008 server, enable and start the DHCP service.
5. On the SBS2008 server, run this at a command prompt:
netsh dhcp server import c:\dhcp.data 192.168.0.0  (substitute your internal network subnet).

Tags: CTIW.exe, dhcp, Manage Router, SBS 2008