Code:
[/boot/kernel]% ls mac_*
mac_biba.ko* mac_ifoff.ko* mac_mls.ko* mac_partition.ko*
mac_seeotheruids.ko* mac_test.ko* mac_bsdextended.ko* mac_lomac.ko*
mac_none.ko* mac_portacl.ko* mac_stub.ko*
This means you can load the module dynamically with
kldload(8) and
loader.conf(5). There is no need to compile a new kernel.
If you really want to add it to the kernel statically, then
mac_portacl(4) has the instructions for that ...
You give us very little information regarding the "instable behavior", Which version of freebsd are you using? Do you see any error messages? What command are you using exactly?
I would not recommend using this "feature" ... You can use the pf firewall and/or tcpwrappers to achieve largely the same effect ...