:: increasing and lowering kernel securelevel in FreeBSD ::

1. to increase kernel securelevel just type:
sysctl kern.securelevel=1
OR
sysctl kern.securelevel=2
and so on

the results will be:
# sysctl kern.securelevel=1
kern.securelevel: -1 -> 1

# sysctl kern.securelevel=2
kern.securelevel: 1 -> 2

2. to lower the secure level you'll need to write the commands in /etc/rc.conf and have your machine rebooted

edit /etc/rc.conf and put these entries:
kern_securelevel_enable="YES"
kern_securelevel="-1"
# this is just an example to lower the securelevel to -1

and reboot