FreeBSD 5.3-BETA2 is now available. Debugging is still turned off by default for BETA2 but will be turned on for the next BETA3. The announcement states “debug.mpsafenet (multi-processor safe network stack) is still. turned off. by default. The latest version of this article has been updated to reflect on the release of the new version of the operating system for the first time in the last two years of this year.”]
Source: https://taosecurity.blogspot.com/2004/08/freebsd-5.html