FreeBSD jail how-to in a nutshell

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Jail HOWTO
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J=/usr/local/jail/00.00.00.101
mkdir -p $J
cd /usr/src
make installworld DESTDIR=$J
cd etc
make distribution DESTDIR=$J

cd $J
mount_devfs devfs $J/dev
ln -sf kernel dev/null  # [Edit]: changed from this 9 April 2007: ln -sf kernel dev/null

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## /etc/mail/hostname.mc
DAEMON_OPTIONS(`Port=smtp, Name=MTA, Addr=sushi.example.com')dnl
DAEMON_OPTIONS(`Port=smtp, Name=MTA_localhost, Addr=127.0.0.1')dnl
DAEMON_OPTIONS(`Port=smtps, Name=TLSMTA, Addr=sushi.example.com, M=s')dnl
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## /etc/ssh/sshd_conf
ListenAddress IP.OF.HOST.MACHINE
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## /etc/rc.conf
ifconfig_em0_alias1="inet 00.00.00.101 netmask 255.255.255.255"

## jail stuff
# general settings
jail_enable="YES"
jail_list="miso" # add to list for more jails

# jail specific settings for jail "miso"
jail_miso_rootdir="/usr/local/jail/00.00.00.101"
jail_miso_hostname="miso.example.com"
jail_miso_ip="00.00.00.101"
jail_miso_interface="em0"
jail_miso_exec="/bin/sh /etc/rc"
jail_miso_devfs_enable="YES"
jail_miso_procfs_enable="YES"
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## Load the entropy for sshd
mount_devfs devfs /usr/local/jail/00.00.00.101/dev
jail /usr/local/jail/00.00.00.101 miso.example.com 00.00.00.101 /bin/sh
sh /etc/rc
exit
umount /usr/local/jail/00.00.00.101/dev

# Let 'er rip
/etc/rc.d/jail start