h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Been asked for help by a friend, but don;t know windows networking myself, so shall post here what I have If anyone has any (polite!!) suggestions, I'd be very grateful!

Basically he doesn't want the DHCP requests to cross over, so each server deals only with its own clients.
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Basically I need to connect a NT4 DHCP server to a Windows 2003 DHCP server
- without clients being able to get IPs from the wrong server.  It's a
total nightmare - especially as the NT4 DHCP server shuts down as soon as
it spots another one on the network.

> and

SERVER1 is a DHCP server with one NIC
SERVER2 is a DHCP server with two NICs, one static and one obtaining automatically
Will SERVER2 NIC get it's IP from SERVER1? Will SERVER1 clients get their IP from SERVER2 - I hope not 'cause the NICs will not be bridged.

Hmmm... Due to the nature of the DHCP protocol, I don't think it's possible to run two DHCP servers on the same network segment without causing a lot of grief - when a client sends out a DHCP request, both servers may respond.

The only way I know of to work around this is to segregate your network into subnets with each client only able to route DHCP requests to one server.

How are the machines interconnected?

Let's start with:
Internet Uplink (if there is one involved in the equation)
Server 1 NIC (is this static or dynamic?)
Server 2 NIC S (for static)
Server 2 NIC D (for dynamic)
Client Group 1 (should get IP addresses from Server 1)
Client Group 2 (should get IP addresses from Server 2)
Lettered Hubs, i.e. Hub A, Hub B, Hub C

If you lay out for me how what is connected to what it will make it a lot easier for people to help...

Without knowing the layout I can't really comment, but I'm tempted to say scope the DHCP servers according to your needs and manually set up the IP addresses for each PC so it talks to the required DHCP server.

Thanks for the replies peeps, have forwarded your info on and shall post anything I receive.

OK, have a reply to your replies, please note this only makes vague sense to me as am not a Windows Networking Geek

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The reason for this horrible set-up is as follows.
We have a NT4 network running happily, this is SERVER1. We are starting a new service whereby we are going to imagecast PCs on behalf of our clients - this requires a DHCP server - hence SERVER2 - We will be imagecasting 100s of PCs at a time so would run out of IPs very quickly if SERVER1 was the only DHCP server.
Clients of SERVER1 need to be able to access certain files on SERVER2. SERVER2 Clients are going to be IT dimwits, and we do not want them anywhere near SERVER1! Hence the need for two seperate networks, with different IPs, but with file sharing and each having it's own DHCP server.
This is how I see it being set-up at the moment...
SERVER1 - has one NIC which is STATIC 10.6.0.2
Windows NT4 Small Business Server with SP5/6
This is the DHCP Server for all office PCs in address range 10.6.0.x (Client PC Group1)
SERVER2 - has two NICs
Windows 2003 Server Standard Edition
NIC1 obtains it's IP from SERVER1 10.6.0.100
NIC2 is STATIC 10.10.0.1
This is the DHCP server for config PCs in address range 10.10.0.x (Client PC Group2)
All of the Client Group1 PCs, SERVER1 and SERVER2 NIC1 are connected to a switched network and are physically wired.
All of the Client Group2 PCs and SERVER2 NIC2 are connected via a network hub - THIS HAS NO PHYSICAL CONNECTION TO SERVER1, CLIENT GROUP1 PCs OR THEIR NETWORK SWITCHES.
I *believe* that SERVER2 will only be able to serve DHCP requests via NIC2, and not on NIC1 as it is not static.
This may seem a daft question, but if the network connections NIC1 and NIC2 are NOT bridged, can NIC1 (incorrectly) obtain it's IP from SERVER2 via NIC2??? - Does that make sense???
When people talk about network segments, my brain starts to fail as when a client PC gets it's IP from a DHCP server it does not have any config - so how does it know which segment it should be in?

If NIC1 and NIC2 are not bridged, you should have no problem as long as you set the static IP on NIC2 to be in a different subnet the dynamic address served up to NIC1 (which you have - 10.6.x and 10.10.x).

When you need to access information from Server 2 through Server 1, the easiest way would probably be drive mappings (Server 2's Q: drive would map to \\server1\path\to\info\, for example) or replication.

I run a similar setup on my home network - Server 1 is my ISP's DHCP server which dispenses an IP address to Server 2 NIC 1 (24.150.x.x). Server 2 runs a DHCP server on NIC 2 (static at 192.168.1.1) which is plugged in to the local hub and dispenses IPs (192.168.1.x) to the LAN.

A DHCP server will never try to serve IP addresses on a dynamic NIC.

Your question's not daft. If NIC1 and NIC2 are not bridged, NIC1 can't see NIC2 because they are not physically connected.

The easiest way to think of this for me is to think of Server2 NIC1 as a regular Client Group 1 NIC. Server2 just happens to have another network connected to it.

With the setup you've described, the DHCP servers shouldn't actually be able to see each other. If they can, something is wrong - possibly a misconnected cable?

Apologies - the first sentence should read:

"If NIC1 and NIC2 are not bridged, you should have no problem as long as you set the static IP on NIC2 to be in a different subnet _from_ the dynamic address served up to NIC1."

Thanks ION, much appreciated, have forwarded this, see what happens next

Have a beverage of choice

No problem! Happy to help.

I think I'll have the .

Something we found at work.

The fastest DHCP server always gets the job done first

One DHCP connected to the college net (called Snp) Snp= 1.22gig 100meg LAN WinNT/PDC domain 1

Us, DHCP connected to the College net (called Bos) Bos= 800MHz 10meg LAN WIN2K PDC domain 2

We got IP from Snp not Bos, Ended up putting a Linux box in for routing.