Three FreeBSD 6 questions

[SiteRollout.com]

Many thanks for all the replies guys. I used the following method pasted
below remotely without having to boot up in single user mode and it worked
fine to upgrade from 6.0 to 6.1/6.2, so I'm sharing with all in case anyone
needs to do the same.

However I want to downgrade from 6.2 PRERELEASE to 6.1 as I'm getting this
message on one server:

This system is running FreeBSD 6.2-PRERELEASE.
FreeBSD Update is only designed to track FreeBSD Security
and Errata branches and cannot update this system

1.) Do I need to downgrade to get the latest security updates?

2.) Can I "rm -fr /usr/src/" to delete everything and pull the latest files
via cvsup again to perform a clean install of 6.0 STABLE(which is currently
6.1)

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Remote server system upgrade:
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Edit cvsupfile

# nano /etc/cvsupfile

*default  host=cvsup2.FreeBSD.org
*default  base=/usr
*default  prefix=/usr
*default  release=cvs
*default  tag=none
*default  delete use-rel-suffix
*default tag=RELENG_6
src-all
ports-all
doc-all

# cvsup -g -L2 /etc/cvsupfile

# make buildworld

Now edit a custom kernel if you need to make specific changes

# uname -a
	FreeBSD server9.site-rollout.co.uk 5.3-RELEASE FreeBSD 5.3-RELEASE
#0: Fri Nov  5 04:19:18 UTC 2004     
	root at harlow.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386

# cd /usr/src/sys/i386/conf
# cp GENERIC FOOBAR

# cd /usr/src/
# make buildkernel KERNCONF=FOOBAR

# make installkernel KERNCONF=FOOBAR

Lets backup your existing /etc directory just incase something goes wrong.

# cp -Rp /etc /home/backupetc

# mergemaster -p

Add following entry to /etc/groups if it doesn't exist

audit:*:77:

# make installworld

Now all of the system userland will be installed. This will take 5-10 mins
or less. Once the system userland has been installed you need to do the most
important step and also most confusing at times. You need to run
'mergemaster'

# mergemaster

You will see the mergemaster application start comparing your existing /etc
directory config files and passwd and group files and other files and it
will start prompting you if you want to either install the files or delete
them or merge them. For the majority of the files you can just tell them to
safely install.

DO NOT EVER INSTALL A NEW master.passwd, passwd or group files. You also be
careful about replacing the /etc/mail/aliases and /etc/rc.firewall firewall
file if you have a custom IPFW firewall created. If you do you will lock
yourself out. If you do happen to install a new password file you will need
copy back your old one from the backup you just made.

% At prompt asking you what you to do or showing you part of a file. Press
'q' and then 'i' to install the file or 'd' to delete it.

Just select 'q' and then 'i' for the most of them except the files I
mentioned above or any other files you have edited with custom entries for
your system.

You will then be prompted to build the new device tree if you installed the
MAKEDEV during mergemaster ( you should have ) select 'y' and let it build.
It will then maybe ask you to rebuild the 'aliases' file. Select 'y' After
that it will ask you if you want to delete the temp root directory. Select
'y'.

You now have a updated system and need to reboot. Be sure to reboot shortly
or it will cause possbile problems if you do this from a remote host.

# shutdown -r +1

The system will reboot and you can login and startup any services that you
need to.

If the system does not come back up and you have tried installing a firewall
have a technician look at the local console and tell them to soft reboot the
server with 'ctrl + alt + del'. When he system is booting up you can tell it
you want load a custom kernel by pressing any key other then 'enter' when
prompted. Then you type.

% unload
% boot kernel.GENERIC
or
% boot kernel.old
% boot kernel.prev

This depends on what your old kernel file was called most systems will have
a kernel.GENERIC on them unless you removed it.

That will get the system backup and you can fix any errors with the
firewall.

Finally, delete any unwanted files in /user/

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