kb893066 is a Microsoft Windows XP critical update for a bug on vulnerabilities in TCP/IP which could allow remote code execution and denial of service.

Some of the known issues that you should know before applying kb893066 are:

1. After you install the updated version of security updatekb893066 on a Windows 2000-based computer, you may notice that there is no Remove button for the KB893066 entry in the Add or Remove Programs (ARP) tool in Control Panel.
2. There will be some problem on computers that are running Microsoft Windows XP with Service Pack 1 (SP1). Some networking programs and tools that send manually crafted Transmission Control Protocol (TCP) packets over raw Internet Protocol (IP) sockets may stop working.

   This behavior may also affect programs and tools that send User Datagram Protocol (UDP) packets.

3. Network connectivity between clients and servers may not work after you install security update kb893066.