f7fcab81_eeBSD_vs_Linux_vs_Windows_2000__Linux
[0] Security [FreeBSD] FreeBSD has been the subject of a massive auditing project for several years. All of the critical system components have been checked and rechecked for security-related errors. The entire system is open source so the security of the system can and has been verified by third parties. A default FreeBSD installation has yet to be affected by a single CERT security advisory in 2000.3 FreeBSD also has the notion of kernel security levels. These are much more powerful than simple run-levels since they allow the administrator to completely deny access to certain operating system functions such as reading /dev/mem, changing file system flags, or writing to disks without mounting a filesystem. FreeBSD includes a very robust packet filtering firewall system and many intrusion detection tools. [Windows 2000] Microsoft claims that their products are secure. But they offer no guarantee, and their software is not available for inspection or peer review. Since Windows is closed source there is no way for users to fix or diagnose any of the security compromises that are regularly published about Microsoft systems. [Linux] 
The open source nature of Linux allows anyone to inspect the security of the code and make changes, but in reality the Linux codebase is modified too rapidly by inexperienced programmers. There is no formal code review policy and for this reason Linux has been suceptible to nearly every Unix-based CERT advisory of the year. This problem is compounded by the fact that distributions like Red Hat tend to turn on notoriously insecure services by default. However, Linux does include a very robust packet filtering firewall system and many intrusion detection tools.
FreeBSD vs Linux vs Windows 2000
Linux