running freebsd in read only mode

[Dan]

Hello,

   I'm looking into how i can run freebsd in read-only
mode. I looked around for info on this, but was
unsuccesful at finding anything that helped me in my
particular situation. I'm involved in a security
contest kind of like defcon at my college. Of course i
picked FreeBsd as my O.S. to secure. I am on the
defensive side of the game, and get points for the
more access and services i allow to the attackers. So
here is the situation. What i would like to be able to
do is boot into freebsd and have it be completely
read-only. For example, if i give a user shell access
they can't change anything, they can use the programs,
but not create or delete anyfiles what so ever. I want
to be able to run a lot of services, and not allow
succesful attacks to change anything on the compute
that way they can have telnet and all the weekest
protocls freely open, and even if they sniff my
administration password through a man in the middle
attacker or what not they can't change it or do
anything to affect the comp.
    Any suggestions, or help would be greatly
appreciated.

   Dan

__________________________________________________
Do you Yahoo!?
The New Yahoo! Search - Faster. Easier. Bingo
http://search.yahoo.com