Multiple IP-addresses on a Network Card

by Johannes Helmig [Published on 1 July 2000 / Last Updated on 1 July 2000]

This page covers both Windows95/98 and Windows NT4/2000.

Sometimes it is necessary to assign to a Networking card more than
one IP-address:

Windows NT4 and 2000 :

In the Network-Properties, Tab: "Protocols", "Properties" of the "TCP/IP-protocol":

click on the button: "Advanced", then on "Add" to define additional IP-addresses.
Although not requested by Windows NT on exiting the Network properties, you need
to reboot your system so that the new IP-address becomes effective.

You can check the IP-addresses
assigned to a network card
by opening a Command-Box
and running : "IPCONFIG"



Windows95/98:

Assigning multiple IP-addresses to a network card is not as simple as under Windows NT,
there is no possibility in the Properties of TCP/IP-protocol to define this, it is required to
edit manually the Registry to achieve this job:

Included in the Win98 Resource Kit (chapter 15 page 607) but not documented anywhere
else by Microsoft:
Assigning multiple IP Address's to a single NIC under Win98.

Multiple IP Address's can be assigned to any given Network adapter.
To do this, you must use the registry editor (regedit.exe).

The usual warning:
Be carefully making changes to your system registry !
A wrong change can make your system inoperational !
It is strongly suggested to make a backup of the registry
before making the modifications shown below.

1. Run Regedit.exe

2. Drill down into HKEY_LOCAL_MACHINE\Enum\PCI for PCI Ethernet adapters,


or HKEY_LOCAL_MACHINE\Enum\ISAPNP for ISA-Plug-and-Play adapters
or HKEY_LOCAL_MACHINE\Enum\Root\Net for ISA-Non-Plug-and-Play adapters:


3. Search all sub-keys until you locate the one with the "DeviceDesc" and "Mfg"
matching your network card. Look for the value which is set for the "
Driver" entry.
It should be like Net\00xx.

4. Now drill down into HKEY_LOCAL_MACHINE\Enum\Network\MSTCP\00xx,
where xx is the value determined from step 3.


5. Look what the value is set for the "
Driver" entry.
It should be like NetTrans\00yy.

6. Now drill down into
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\NetTrans\00yy,
where yy is the value determined from step 5.


7. Edit the value of the entry "IPAddress" and append it with a comma and
then the 2nd IPAddress (example. "192.168.1.1,192.168.1.21" or
"192.124.36.176,192.169.254.254.1" ) With this configuration you adapter
responds to both IP addresses.

8. You must also edit and append the "IPMask" value as well, and must
specify the correspondent subnet mask for each listed IP address.


9. Reboot.

10. Run
Winipcfg.exe and you will see a button to the right of your
listed IP address to show you the next IP of that adapter.


Note 1:
While I have no problem following these steps on Windows95 with a
Non-Plug-and-Play NE-2000 networking card, I could not find on Windows98-SE
with a Realtek-PCI-card the link from s
tep 3 to step 4.

So I did it the "Brute Force" method:

I simply searched the registry for the existing IP-address , which did bring me
immediately to
step 6, where I then made the changes , my system did then
recognize both IP-addresses.

Note 2:
If you need to use DHCP for one of you IP addresses, set the adapter up
first to use DHCP as normal. Follow the all the steps listed above and
append the "0.0.0.0" with the fixed IP address you wish to assign to it.
(ie. "0.0.0.0,169.254.254.1" )

I don't know what the limit of IP addresses is per Network adapter, but I
believe having up to 4 is no problem.

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