topic Two DHCP/bootp Servers on the Same Network? in Windows Server 2003

Two DHCP/bootp Servers on the Same Network?

Jay Bollyn — Tue, 01 Mar 2005 20:15:40 GMT

In my office network, we have a (Sun OS) UNIX server running bootp, which is our main production system for the university.

If I configure my (test) win2k3 server with the role of DHCP server, what would happen? How would the clients choose between the two DHCP/bootp servers on the network? I need as much *detail* as possible.

Please note that I would not dare do this kind of test in a production environment. I am mainly looking for detailed technical information, about win2k3 DHCP, and to a lesser extent about bootp.

Thanks.

:-) Jay

Re: Two DHCP/bootp Servers on the Same Network?

Gary Cooper_1 — Wed, 02 Mar 2005 04:18:07 GMT

Hi Jay,

This should work. The client will broadcast a DHCPREQUEST message. If there's more than one server listening then it ignores subsequent replies. The important thing here is to make sure that each DHCP server has a unique IP addres range, because it won't know what IP addresses have been leased from the other server.

Have a look at http://support.microsoft.com/?kbid=120932

Regards,

Gary

Re: Two DHCP/bootp Servers on the Same Network?

Tim Malnati — Wed, 02 Mar 2005 18:13:18 GMT

What Gary mentioned is correct but there is a lot more to consider if you have any intention of moving toward production at some time. Make sure you do your testing on a subnet that can NOT be seen by your production server environment (from a DHCP routing perspective)! Doing this sort of stuff in a lab environment is probably best.
-> ALL static IP hosts should have a reservation and this needs to be setup on ALL DHCP servers that can potentially service the client (not blocked by a router).
-> Make sure that the DHCP service is stopped on a Windows based server (or disconnected from the network) during the creation and population of DHCP scopes intended for the static IP hosts. Unix/Linux systems use a configuration file that can be moved in when the time is right.
-> Heavy use of DHCP is usually not preferred on a Windows based machine where it is very disk intensive in this environment and it also hammers the registry.
-> Unix/Linux based DHCP servers have all sorts of bells and whistles like grouping, preferred server designation, configurable denial, dynamic DNS integration and more.
-> The bottom line is that Windows based DHCP is usually a better alternative when Unix/Linux administrative resources are not available in house.
-> The newer Windows based clients have some protection from two clients attempting to use the same IP. But what about PDA's, printers, or whatever?

Re: Two DHCP/bootp Servers on the Same Network?

Jay Bollyn — Thu, 03 Mar 2005 20:02:39 GMT

Thanks, I understand this better now.

:-) Jay