Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

We are setting up a routing link between the Windows Server 2008 networks of two different buildings in my organisation. Each network uses a different IP addressing scheme (one uses public addresses, the other one uses private), but the goal is having a single Windows Server domain across the gap between the buildings. The link is provided by a 100-Mbps point-to-point line.

I have always understood that you should not have more than one DHCP server on a network. However, we are planning to put a domain controller on each building, and each domain controller will be a DNS server and a DHCP server as well. The intention is that a machine booting up in building A gets its IP address from the DHCP server closer to it, in building A, while a machine booting up in building B gets an address from the DHCP server in building B. Since the two buildings will be linked and the network will be only one, will this work? How can I avoid that a machine booting up in building A gets an address from the DHCP server in building B (or vice versa)?

Thanks.

share|improve this question
    
possible duplicate of Can I have multiple DHCP servers on one network? –  RobM Sep 1 '12 at 21:35
add comment

2 Answers

up vote 8 down vote accepted

Yes, this will work. DHCP is a broadcast based technology and since broadcasts are not forwarded across routers by default (unless you configure them to by enabling broadcast forwarding or configuring a dhcp helper address) you should have no problems with machines getting their ip addressing information from the correct DHCP server.

share|improve this answer
    
Also, the computers in buildings A and B are not on the same network if they're on different subnets. They may be in the same AD domain but the networks are different, so make sure you set up each subnet in AD Sites & Services. –  joeqwerty Mar 4 '10 at 13:27
    
Thanks. Interesting to know that about broadcast. :-) –  CesarGon Mar 4 '10 at 13:27
add comment

If you're going to have multiple DHCP servers on the same network I would recommend using DHCP exclusions. Without the use of exclusions clients may receive duplicate IP addresses.

For example, configure the DHCP IP address scope of Building A's DHCP server to include IP's 10.0.0.1 - 10.0.0.99 and Building B's DHCP server to include IP's 10.0.0.100 - 10.0.0.254.

This is also a good way to monitor whether or not the correct DHCP server is serving the correct building IP address.

share|improve this answer
    
-1 for inaccuracy--In this particular scenario, DHCP would not have been broadcasted across the routers (as was mentioned above) –  Josh Brower Mar 8 '10 at 3:03
    
@Dave: As I said in the original post, each building uses a different IP addressing scheme; one uses public addresses, the other one uses private addresses. So I don't think that exclusions are necessary in any case, because there is no risk of overlap between the address ranges. –  CesarGon Mar 8 '10 at 20:27
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.