IP Filter has been mostly tested under IRIX 6.2. It should work under IRIX 6.3
as well. Under IRIX 5.3, it has been successfully compiled and linked in the
kernel, but not tested. Compilation under IRIX >= 6.4 is not yet supported.

To build a kernel with the IP filter and install it on your system,
follow these steps:

	1. edit the top-level Makefile to
		a) comment-out the IPFLKM definition.
			This means changing the line reading:
				IPFLKM=-DIPFILTER_LKM
			to
				#IPFLKM=-DIPFILTER_LKM
		b) select the system's compiler (cc)
			This means changing the line reading:
				CC=gcc
			to
				CC=cc
		b) enable full optimization
			This means changing the lines reading:
				DEBUG=-g
				CFLAGS=-I$$(TOP)
			to
				DEBUG=
				CFLAGS=-O2 -I$$(TOP)

        1. do "make irix" (Warning: GNU make is not supported, so if it has
	been installed on your system, verify your path and/or do "which make"
	to guarantee that IRIX's /sbin/make has precedence)

        2. do "make install-irix" as root
	   (a new kernel will be automatically built)

	3. determine the filtering rules and place them in /etc/ipf.conf
	   and /etc/ipnat.conf

        4. do "init 6" as root to reboot with the new kernel

	After restarting, the filter should be active and behaving according to
	the rules loaded from /etc/ipf.conf and /etc/ipfnat.conf.

	These files can be changed at any time, and reloaded using the
	following command sequence:

	# sh /etc/init.d/ipf stop; sh /etc/init.d/ipf start


To remove the IP Filter from your kernel, follow these steps:

	1. Delete the /var/sysgen/boot/ipfilter.o file

	# rm /var/sysgen/boot/ipfilter.o

	2. If SGI's ipfilter.o had been previously installed, restore it
	back to its original location

	# mv /var/sysgen/boot/ipfilter.o.DIST /var/sysgen/boot/ipfilter.o

	3. Build a new kernel

	# /etc/autoconfig

	4. Delete the /etc/rc2.d/S33ipf symbolic link

	# rm /etc/rc2.d/S33ipf

	5. Reboot

	# init 6


ADDITIONAL NOTES:

	- The IP filter uses the same kernel interface to the IP driver as
	SGI's ipfilter. In fact, it is installed in place of SGI's
	/var/sysgen/boot/ipfilter.o module, after renaming it (if installed)
	to /var/sysgen/boot/ipfilter.o.DIST. You should ensure that SGI's
	ipfilterd daemon is not running simultaneously, since this package uses
	the same major device number.

	- We have not tested IP Filter on a multiprocessor machine yet.
	However, feel free to try it and send your experiences/patches
	back to marc@CAM.ORG. SGI prescribes that kernel code be built on such
	systems with -D_MP_NETLOCKS -DMP. Therefore, these flags should
	probably be uncommented on the DFLAGS line of IRIX/Makefile if your
	machine has more than one processor.

	- It is also possible to build IP Filter as a dynamically loadable
	kernel module (by retaining the IPFLKM=-DIPFILTER_LKM definition in the
	top-level Makefile), but this is not recommended other than for testing
	and debugging purposes, because the only possible method for dynamic
	attachment to the IP stack (instruction patching) is highly dependent
	on the processor architecture. The code provided has only been tested
	with IP22 CPU boards and can sometime cause panics during loading due
	to a potential race condition.


CREDITS:

	IP Filter was ported to IRIX by Marc Boucher <marc@CAM.ORG>

	Marc Boucher wishes to thank the
		ICARI Institute (http://www.icari.qc.ca)
	and
		Aurelio Cascio <aurelio@toonboom.com>
	for their financial support and testing facilities, respectively.