FreeBSD upgrade on production server

[Lowell Gilbert]

"SUPPORT" <support at bluetooth-shop.sk> writes:

> I wish to upgrade my production firewall / mailserver / DNS server from
> 4.3 to 4.8. The simplest way seems to be use of CVSUP. OK, but...

Right, so far.

> Is it safe ? 

It's not completely safe.  Of course, neither is running a
two-and-a-half year-old release of any operating system 
connected to the Internet.  Risk is something you have to 
manage, not avoid.

>              What should I backup ?

Everything you'd mind losing.  For me, that's mostly /etc,
/usr/local/etc, user data, kernel configs, and the log directory.

>                                     There is running well-configured
> sendmail - are there some changes in its configuration between
> versions 8.11.3 used in FreeBSD 4.3 and 8.12.8p1 used in
> FreeBSD 4.8.

There certainly are some changes.  Some of them are related to
important security fixes.  You will need to merge your configuration
into the updates.

> This is my only mailserver and I don't have an secondary
> if something fails...

Well, the safest approach is to have a spare system, and build the
modifications on that.  If you can't do that, then almost as safe (and
actually safer from your own oversights) is to have a spare machine to
try out the upgrade on so you get used to the procedure.  If you
really can't spare a machine for any of these things, accept some
downtime and make sure you're *very* careful as you go through the
documented procedure.

> Please, advice if you have some know-how :-)))

All of my specific advice is *in* the Handbook.  If I had any more
advice, I'd submit it to, well, the Handbook.

Good luck.