MAC_IFOFF(4)						   BSD Kernel Interfaces Manual 					      MAC_IFOFF(4)

NAME

     mac_ifoff -- interface silencing policy

SYNOPSIS

     To compile the interface silencing policy into your kernel, place the following lines in your kernel configuration file:

	   options MAC
	   options MAC_IFOFF

     Alternately, to load the interface silencing policy module at boot time, place the following line in your kernel configuration file:

	   options MAC

     and in loader.conf(5):

	   mac_ifoff_load="YES"

DESCRIPTION

     The mac_ifoff interface silencing module allows administrators to enable and disable incoming and outgoing data flow on system network inter-
     faces via the sysctl(8) interface.

     To disable network traffic over the loopback (lo(4)) interface, set the sysctl(8) OID security.mac.ifoff.lo_enabled to 0 (default 1).

     To enable network traffic over other interfaces, set the sysctl(8) OID security.mac.ifoff.other_enabled to 1 (default 0).

     To allow BPF traffic to be received, even while other traffic is disabled, set the sysctl(8) OID security.mac.ifoff.bpfrecv_enabled to 1
     (default 0).

   Label Format
     No labels are defined.

SEE ALSO

     mac(4), mac_bsdextended(4), mac_lomac(4), mac_mls(4), mac_none(4), mac_partition(4), mac_portacl(4), mac_seeotheruids(4), mac_test(4), mac(9)

HISTORY

     The mac_ifoff policy module first appeared in FreeBSD 5.0 and was developed by the TrustedBSD Project.

AUTHORS

     This software was contributed to the FreeBSD Project by Network Associates Labs, the Security Research Division of Network Associates Inc.
     under DARPA/SPAWAR contract N66001-01-C-8035 (``CBOSS''), as part of the DARPA CHATS research program.

BUGS

     See mac(9) concerning appropriateness for production use.	The TrustedBSD MAC Framework is considered experimental in FreeBSD.

     While the MAC Framework design is intended to support the containment of the root user, not all attack channels are currently protected by
     entry point checks.  As such, MAC Framework policies should not be relied on, in isolation, to protect against a malicious privileged user.

BSD
								 December 10, 2002							       BSD