This article will explain briefly how to keep your FreeBSD box in sync with the STABLE release track. FreeBSD-STABLE is the development branch from which major releases are made. Changes go into this branch with the general assumption that they have first gone into FreeBSD-CURRENT (bleeding-edge track) for testing. This is still a development branch, however, and this means that at any given time, FreeBSD-STABLE may or may not be suitable for any particular purpose. It is simply another engineering development track, not a resource for end-users.

For these reasons, it's not recommended to blindly track FreeBSD-STABLE, and it is particularly important not to update any production servers to FreeBSD-STABLE without first thoroughly testing the code in a development environment.
If you do not have the resources to do this, it's recommended that you run the most recent release of FreeBSD, and use the binary update mechanism to move from release to release.

Use cvsup with this supfile to get the latest sources. This is the most recommended method, since it allows you to grab the entire collection once and then only what has changed from then on.
You can run cvsup from cron and keep your sources up- to-date automatically. You have to customize the sample supfile above, and configure cvsup for your environment. If you want help doing this configuration, simply type:

# pkg_add -f ftp://ftp.freebsd.org/pub/FreeBSD/ports/i386/packages/Latest/cvsupit.tgz

Next short list will do the work :

    1. Sync the sources 
      - cvsup /etc/cvsupfile
    2. Remove /usr/obj (from a previous make world) 
      - cd /usr/obj
      - chflags -R noschg *
      - rm -rf *
    3. cd /usr/src
    4. make -j4 buildworld (and than go kill some time . . . :-) 
    5. make buildkernel KERNCONF=YOURKERNCONF
    6. make installkernel KERNCONF=YOURKERNCONF
    7. reboot your precious machine
    8. cd /usr/src 
    9. make installworld
   10. mergemaster   

Done. All of this assumes you're already running FreeBSD 4.x, that you already have a working kernel configuration, and that your computer has access to one the cvsup servers around the world (preferably one close to you).
If you need more detailed information, look here .