Multiple IP addresses to one NIC, but advanced IP settings window only shows one?

Question

The ipconfig of my Windows Server 2003 server shows that the IP addresses 10.0.0.3, 10.0.0.11, and 10.0.0.12 are assigned to it. However, when I look in the Advanced TCP/IP Settings window for that connection, I only see the IP address of 10.0.0.3 listed there.

In the Support tab for the connection, it shows that it's connected through 10.0.0.12, and in the Support > Details window, it shows all the previously mentioned IP addresses.

Where are these phantom IP addresses being stored and how can I free them up so I don't have any IP conflicts?

Answer 1

Nic's that are used in Clustering (whether MSCS or MSNLB) MUST have multiple IP's bound to them. These virtual IP's are always listed in the appropriate role's MMC Snap-in (Cluster Admin for MSCS and NLB Manager in MSNLB). All IP's are listed in the Advanced TAB for TCP/IP Settings of any NIC's involved in a cluster:

(right-click the interface-->properties-->(double-click 'Internet Protocol (TCP/IP)')-->advanced-->(look in the IP addresses window)

It's on you to determine what IP's are available before binding them to a clustered node. Keep an Excel spreadsheet with a workbook for each subnet in your LAN...

Answer 2

You can check the leases of the DHCP server. In windows DHCP servers, it will accept a description field. (Just in case, to get there: Start -> Admin Tools -> DHCP , then expand server -> expand scope -> click Address Leases)

Depending on the function of your server, it might actually be using the separate IPs. RRAS is notorious for this.