# wtap 備份
## install a jail from an ISO

export DESTDIR=/usr/jail/net80211_0
sudo mkdir -p $DESTDIR

Mount the install media on `/mnt`(change `cdimage.iso` to your ISO).

sudo mount -t cd9660 /dev/`mdconfig -f cdimage.iso` /mnt
cd /mnt/usr/freebsd-dist/

Install just the base system.

tar -xf base.txz -C $DESTDIR

Also install the tarball to `/usr/jail/net80211_1`.
## configuration for jail
Copy jng (jng stands for "Jail Netgraph", which is a shell script for creating netgraph in jail) to `/usr/sbin`.

sudo cp -v /usr/src/share/examples/jails/jng /usr/sbin/

### creating `devfs.rules`
Create `/etc/devfs.rules` and open it in text editor:

[devfsrules_jail_net80211=5] add include $devfsrules_hide_all
add include $devfsrules_unhide_basic
add include $devfsrules_unhide_login
add path 'tun*' unhide

Save and close file.
### configure `jail.conf`
Append the following config in `/etc/jail.conf`:

net80211_0 {
    host.hostname = "net80211_0";   # hostname
    path = "/usr/jail/net80211_0";     # root directory
    exec.clean;
    exec.system_user = "root";
    exec.jail_user = "root";
    # ##########################################################################  
    # netgraph/vnet config info
    # ng0 is my vnet
    # em0 is my physical network interface connected to the LAN (use ifconfig)
    # jng is located in /usr/sbin/
    # net80211_0 is my jail name
    # ##########################################################################  
    vnet; 
    vnet.interface = "wlan0";               # vnet interface(s)
    exec.prestart += "jng bridge net80211_0 bridge0";   # bridge interface(s)
    exec.poststop += "jng shutdown net80211_0";      # destroy interface(s)

    # Standard stuff
    exec.start += "/bin/sh /etc/rc";
    exec.stop = "/bin/sh /etc/rc.shutdown";
    exec.consolelog = "/var/log/jail_net80211_0_console.log";
    mount.devfs;          #mount devfs
    allow.raw_sockets;    #allow ping-pong
    devfs_ruleset=5;    #devfs ruleset for this jail
    mount.devfs;
}

Also add net80211_1 with some fields modified.

Save and close the file.