TechTips - Windows Server 2008 Service Pack 2 Re-enables All Disabled NICS

I recently started the tedious task of upgrading or rebuilding all of my Windows 2003 servers to Windows 2008 Servers, the process has been interesting to say the least. I have learned that you have to install .NET framework 1.1 in order to successfully install IIS 7.5 and more recently I found that Server 2008 SP2 re-enables all NICs on your server after it is installed. This is something that administrators will want to be aware of when they are upgrading to Server 2008.

This may not be a big issue to many administrators who are upgrading to 2008 SP2 but for some it could potentially be a huge issue especially if they are using Virtual Machines or failover NICs (like I do). When using VMs you will could potentially have many different virtual NICs for each VM which after the SP2 update; will be automatically turned on. This can cause problems and conflicts on your hosting server and possibly the VMs.

Another scenario is like how I have my setup, I have two NICS per server (one enabled one disabled) both have identical IP information on them, this is in case one my NICs suddenly fails I can simply enable the other NIC and have little to no down time. When I updated 2008 with SP2 and it kicked all of my NICs on I got all sorts of messages about IP conflicts and my servers went down due to these conflicts. I had to go in and disable all of the suddenly enabled NICs.

This SP2 update is also a problem with Windows Vista; it can enable disabled NICs on your desktop and laptop computers as well. This doesn't seem like as big of an issue as say a server with multiple NICs and multiple IPs but it can be leave a user exposed. Most PCs don't have multiple NIC cards but some organizations might have machines running some VMware products or other virtualization tools that maybe create virtual NICs that might need to be shut off from time to time. Well when you do the upgrade to SP2 it will turn any and all NICs back on. It's not as likely to cause issues for users of Vista but the potential is there so just be aware of it.

So when updating to Server 2008 SP2 or Vista SP2, make sure you are aware of the issue of disabled NICs being enabled. You should probably make a document laying out all of your servers and the NICs they have, making note of disabled NICs, why they are disabled, and make sure you disable them once the Service pack is installed, hopefully stopping any problems before they start.