While it may suck for a few people still using Windows 98, Microsoft says it just isn't feasible to fix a critical hole in the operating system because it would require "re-engineering a significant amount of a critical core component of the operating system". Instead, Microsoft recommends that people who still use the older operating systems protect their PCs by using a network firewall that filters traffic on TCP Port 139. "Such a firewall will block attacks attempting to exploit this vulnerability from outside of the firewall," it said.