I was recently asked about how to change the IP address of an Exchange 2007 cluster.  Here is the information that I shared:

NOTE: Be sure to test this before trying in production.  Each environment and application may respond differently to changes.

For Windows 2003 Cluster
1.    Set Cluster Admin against the local node (.)
2.    Take the Cluster Groups Offline
3.    Change the cluster IP Address resource objects to new addresses within each group
4.    Change Cluster Service to Manual and stop on both nodes
5.    Change physical IP Address/Subnet/Gateway on each node
6.    Check the IP address under HKLM\Cluster\Network Interfaces and HKLM\Cluster\Network by pointing to the present ip replacing the old IP address.
7.    Cleared the DNS entries for the cluster pertaining to the old IP addresses.
8.    Reboot the server (cluster service should start)
9.    Bring resources online

For Windows 2008 Cluster
1.    Open Failover Cluster Management
2.    Take the Exchange Cluster Groups offline (if applicable)
3.    Select the Cluster Name in the left pane.   In the middle pane, scroll down to CLUSTER CORE RESOURCES.
4.    Take Cluster core resource Name and IP address resource offline (right click and select Take this resource offline)
5.    Open the Network Properties on each physical node and Change IP addresses of the Public Network
6.    Register the new IP addresses in DNS (IPConfig /RegisterDNS) on both physical nodes (make sure DNS is up to date)
7.    Back in Failover Cluster Management.  Select the cluster object and then Networks.  Select each cluster network and make sure that the NODE IP address is up-to-date.
8.    Under Cluster Core Resources, go to the properties of the Cluster Name’s IP Address resource. 
9.    In the NETWORK drop down, select the appropriate Subnet object.
        NOTE: If the object does not exist yet, refresh the cluster object, check network settings, and make sure that the Cluster Network is set to “allow clients to connect through this network”
10.    In the Static Address field, change the IP address and apply the settings.
        NOTE: Check the dependencies tab too
11.    Go to the properties of the Cluster Name resource and make sure that the IP address is refreshed with the new IP address
12.    Start Cluster Core services IP and name resources
13.    Update the IP address of the Exchange Cluster Group Resource objects (if applicable)
14.    Start Application Cluster Group’s IP and name (if applicable) (and all other offline resources)
15.    Select Failover Cluster Management in the top left pane and then select Validate a Configuration…  Check for errors and mis-configured objects.

 

FAQ
Do I need to reboot the server nodes?
You might if you plan to move between subnets and/or AD Sites or if the server is not recognizing the network after the IP address change.  Otherwise, no.

Can I switch it back to the old IP address?
Yes but you may need to clear out any caching of that IP address from WINS, DNS, and Network Devices (i.e. routers, switch ports, etc) before switching it back.

Is this something that I can do in production?
Yes but you should limit your changes to a cluster.  The purpose of a cluster is to provide high availability and in this scenario, you need to bring down the resources to complete the change.

How can I use Cluster.exe to update the IP address of the cluster?
You can use Cluster.exe to update the cluster resources that may reflect the IP address but not necessarily the IP address associated with the NIC.

What else should I consider when I change the IP address of the cluster?
If you are changing subnets, the server may belong to another AD site.  Know the affect on Exchange and the clients connecting to it before you make that move.
Also, make sure that the switch port is not statically mapped to an IP address or subnet

Will my Exchange server resources be available during this change?
Do not plan on them being available to clients as the resource groups will be brought offline and connections will most likely be reset during IP address change.

Doug