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.

I have two hosts that have an interface in 4 different LAN subnets (no WANs apply here).

10.1.1.x
10.1.2.x
10.1.3.x
10.1.4.x

Assume that each subnet will need a local service of x.x.x.9 as the desired service to be load balanced. Also assume the two hosts already have the following non load balanced IPs:

10.1.1.11
10.1.1.12

Question

When I set up NLB on the other subnets, am I required to also have a non clustered IP for that host?

Example:

Load Balanced
10.1.1.9
10.1.2.9
10.1.3.9
10.1.4.9


Host1
10.1.1.11  <-- Already Exists
10.1.2.11  <-- Is this needed in addition to 10.1.x.9??
10.1.3.11  <-- Is this needed in addition to 10.1.x.9??
10.1.4.11  <-- Is this needed in addition to 10.1.x.9??


Host2
10.1.1.12  <-- Already Exists
10.1.2.12 <-- Is this needed in addition to 10.1.x.9??
10.1.3.12 <-- Is this needed in addition to 10.1.x.9??
10.1.4.12 <-- Is this needed in addition to 10.1.x.9??

In other words, must all the IPs on this page be on the same subnet?

enter image description here

share|improve this question
add comment

3 Answers

up vote 0 down vote accepted

On each subnet, each server part of the nlb cluster need one ip (it's own) and then one or more virtual ip addresses.

What affect the behaving of NLB is the choice between unicast and multicast: http://technet.microsoft.com/en-us/library/cc782694(v=ws.10).aspx

servers needs one dedicated ip per subnet because you don't manually map the cluster ip to network interface. NLB uses ip interfaces to detect on which network card to publish clusters IP.

Unicast change mac address but need generally to configure switch (which by default don't accept same mac address on more than one port)

share|improve this answer
add comment

No, you do not need a fixed IP per subnet, just one per machine on the subnet you want to manage them on.

share|improve this answer
add comment

Yes each host requires its own IP and if you want to cluster them the cluster also requires an IP. A cluster at a minimum requires 2 IPs, then 1 IP for each additional host

share|improve this answer
    
You can get away with not assigning a local IP but glod help you if the node fails. –  adaptr Apr 3 '12 at 15:29
    
Just to be clear, do I need a local IP per subnet when I'm load balancing N+1 subnets (and already have a per-host IP on a specific subnet)? –  makerofthings7 Apr 3 '12 at 15:38
    
In theory you do not have to have the nodes on the same subnet, however I've never tried to do that with NLB as it defeats the purpose of NLB –  Jim B Apr 4 '12 at 1:08
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.