But: I know FreeBSD can implement virtual interfaces and assign them to jails, so...

Answer: register freebsd5.cs.uwaterloo.ca, assign it to torres as a virtual interface, and then set up a jail that will call itself freebsd5.

Initial Setup

jail wants to know its ip (129.97.15.40) and a user to run as. We don't want to run it as a regular user, nor do we want to run it as nobody, so let's create a new user "bsd5".

Username   : bsd5
Password   : 
Full Name  : freebsd5 controller
Uid        : 1006
Class      :
Groups     : bsd5
Home       : /home/bsd5
Shell      : /sbin/nologin
Locked     : yes
OK? (yes/no): yes
adduser: INFO: Successfully added (bsd5) to the user database.
adduser: INFO: Password for (bsd5) is: (passwd elided)
adduser: INFO: Account (bsd5) is locked.
Add another user? (yes/no): no

Hopefully that will be sufficient. Now, looking at the manpage for jail(8), we see directions for setting up a complete distribution in a jail.

torres# setenv D /usr/freebsd5
torres# cd /usr/src
torres# make world DESTDIR=$D

and wait a long time. Maybe I should have seen if I could have just done a make installworld DESTDIR=$D, but my /usr/obj is probably only half there now.

torres# cd etc
torres# make distribution DESTDIR=$D
torres# mount_devfs devfs $D/dev
torres# cd $D
torres# ln -sf dev/null kernel

That went much more quickly.

Now we run into troubles, because torres is a general purpose server for me, but we have to now restrict it IP wise. jail(8) says to do things like tell services to listen only on the one address: see the section marked "Setting up the Host environment".

So I'm going to leave off of this for now - too much work that'll just have to be tossed when I later get real hardware (I hope).