Windows Server 2003 SP2

Hi I’ve been asked to install SP2 for Server 03 but am a little concerned.
(I need to install it prior to instlaling an update that allows Vista machines to use OWA.)
– http://support.microsoft.com/kb/911829

I was reading through the overview of Server 03 SP2 and came across this:

“New firewall per port; authentication secures traffic between the extranet environment and internal assets that are protected via IPsec domain isolation.”
– http://www.microsoft.com/technet/windowsserver/sp2/data-sheet.mspx

I was wondering how this might affect the current firewall. Could anyone tell me how the installation affected their server/ networks?