Hi
Maybe this will be of help
Link:
http://support.microsoft.com/default.aspx?scid=kb;[LN];287673
The Packet Filter Does Not Enable the Renewal of an External IP Address
SYMPTOMS
========
After you release the Internet Protocol (IP) address on the external
network adaptor of a multiple-homed server with the ipconfig /release
command, the IP address cannot be renewed by using the ipconfig /renew
command.
You may receive the following error message, where X is the number of the
network connection for the external network interface card (NIC):
The following error occurred when renewing adapter Local Area Connection X:
DHCP Server unreachable.
NOTE: This problem only occurs on a Small Business Server 2000-based
server, or on a BackOffice 2000 Server-based server that runs Microsoft
Internet Security and Acceleration (ISA) Server.
CAUSE
=====
This problem can occur because ISA Server puts a Dynamic Host Configuration
Protocol (DHCP) filter on the external network adaptor. After the IP
address is released from this adaptor, it can either have an IP address of
0.0.0.0, or an auto-assigned IP address. ISA Server does not enable this
network adaptor to receive DHCP packets, therefore, it is unable to renew
an IP address lease.
WORKAROUND
===========
To work around this problem, use the following method:
1. Click Start, point to Programs, point to Microsoft ISA Server, and then
click ISA Management.
2. Expand Servers and Arrays, expand Your Server, expand Access Policy,
and select IP Packet Filters.
3. In the right window labeled "Available Packet Filters", select DHCP
Client, and click Configure a Packet Filter.
4. On the DHCP Client Properties page, and under the General tab, click
Enable this filter.
5. Click Start, point to Programs, click Administrative Tools, and then
click Services.
6. Right-click Microsoft ISA Server Control, and then click Stop.
7. A window is displayed that lists the following services that can be
stopped:
Microsoft Scheduled Cache Content Download
Microsoft Web Proxy
Microsoft Firewall
Click Yes to stop these services.
8. At a command prompt, type ipconfig /renew
9. The IP address is renewed. Because the filter is now in place, the
preceding steps are not needed again to release and renew the IP address.
NOTE: If the IP address is ever released, it will not be possible to run
the ipconfig /renew command without disabling the packet filters or ISA.
10. Restart the services that you stopped in steps 6 and 7.
STATUS
=======
Microsoft has confirmed that this is a problem in the Microsoft products
that are listed at the beginning of this article.
Shilpa Sinha
This posting is provided "AS IS" with no warranties, and confers no rights.
