When managing FreeBSD jails without SSH access, the jexec utility becomes your primary tool for gaining shell access. This is particularly common in minimal jail configurations like database servers where SSH might be intentionally disabled for security reasons.

The simplest way to enter a jail is:

jexec [JID] /bin/sh

Where [JID] is the jail identifier which you can find using:

jls

For our SQL server jail (let's assume JID 3), we would execute:

jexec 3 /bin/sh

To execute a single command without entering interactive shell:

jexec 3 /bin/sh -c "ps aux | grep mysql"

For persistent access, you might want to create an alias in your root shell:

alias sqljail='jexec 3 /bin/sh'

To check jail networking from host:

jexec 3 /bin/sh -c "ifconfig"

If you encounter permission issues, verify the jail's configuration in /etc/jail.conf or /etc/rc.conf. Ensure the jail has proper mount points and resources allocated.

For jails using ZFS datasets, you might need to check dataset permissions before accessing:

zfs list -t filesystem | grep jail

Before attempting to access the jail shell, ensure you have:

• Root privileges on the host system
• The jail name or JID (Jail ID)
• Basic familiarity with FreeBSD jail commands

The simplest way to access a jail shell is through FreeBSD's built-in jexec command:

# List all running jails to identify your target
jls

# Access the jail shell (replace 'sql-jail' with your jail name)
jexec sql-jail /bin/tcsh
# or for a standard Bourne shell:
jexec sql-jail /bin/sh

If you know the jail's filesystem location:

# First find the jail path (example location)
chroot /usr/jails/sql-jail /bin/sh

# For a more complete jail environment:
chroot /usr/jails/sql-jail /usr/bin/env -i TERM=$TERM /bin/sh

If your system uses ezjail or other management tools:

# For ezjail users
ezjail-admin console sql-jail

# For iocage users
iocage console sql-jail

For frequent access, consider these setup options:

# Add a custom entry to /etc/fstab for the jail's devfs
devfs /usr/jails/sql-jail/dev devfs rw 0 0

# Create a quick-access alias in your shell rc file
alias sqlshell="jexec sql-jail /bin/sh"

If you encounter problems:

• Ensure the jail is running (jls shows status)
• Verify the jail has proper devfs mounted
• Check for correct root filesystem permissions

When accessing jails as root:

• Limit host root access to trusted administrators
• Consider setting up proper sudo rules for jail access
• Audit jail entry/exit using auditd