HOST Name Resolution Returns Last IP Addr on Multihomed Computer (163923)

SYMPTOMS

On a computer running Windows NT with multiple IP addresses assigned to the same network interface card, resolving the computer's HOST or NetBIOS name will return the last IP address listed in the Network Control Panel Advanced TCP/IP Properties, rather than the first address listed. All other computers on the network that resolve this name will correctly get the first IP address listed.

This can cause problems with applications that are running on a computer that performs a lookup of its own HOST name. One example of this is when you use Microsoft FrontPage and Internet Information Server (IIS) with multiple virtual servers.

WORKAROUND

If you are using DNS for name resolution, you can add an additional A record for the same computer, with a different name. For example, if your computer name is listed in DNS as WEBSERVER, you may also want to add an entry in DNS for WWW that refers to the same IP address. In this case, when you type PING WWW, the name is not resolved locally, but rather at the DNS server, and the correct IP address will be indicated in the reply.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

MORE INFORMATION

The following is an example of this configuration:

HOST name = MACHINE1
Assigned IP Addresses #1= 192.168.1.1
Assigned IP Addresses #2= 192.168.1.2
Assigned IP Addresses #3= 192.168.1.3

If you are at MACHINE1 and type PING MACHINE1, your reply will indicate the 192.168.1.3 address.

If you are at another computer on the network and type PING MACHINE1, your reply will indicate the 192.168.1.1 address.