*BSD News Article 54373


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From: j@uriah.heep.sax.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: IP Forwarding under FreeBSD
Date: 3 Nov 1995 00:11:16 +0100
Organization: Private FreeBSD site, Dresden.
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References: <46ngrd$5hq@bilbo.nask.org.pl> <470e8d$1m8@uriah.heep.sax.de> <4775d9$bo@hptemp1.cc.umr.edu>
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serges  <serges@rocket.cc.umr.edu> wrote:

>: Obsolete.  Use ``sysctl -w net.inet.ip.forwarding=1'' instead.
>
>"Obsolete" as of what release? True the sysctl approach is quicker - that 
>is if you like the idea of editing the kernel image as a matter of course 
>(and not as a hack)

The ``options GATEWAY'' hack has not been removed yet, but in
-current, its only remaining effect is to pre-enable IP forwarding.
(It used to have more side-effects in previous versions.)

Pre-enabling IP forwarding is forbidden by RFC.

sysctl is not a hack, it's a controlled interface to several kernel
variables.  (And yes, they are called ``variables'' since they are not
always constant. :-)  Unlike writing to those variables with kgdb, the
sysctl approach will also continue to work in higher security levels,
where access to /dev/mem is denied.

>: >ii) executed routed with -s option
>
>: Obsolete and dangerous.

>"dangerous" why?

Because it's "routed". :)

It's my understanding that routed is not the technically best piece of
software around.

>... I use it to delete inactive routes 
>created by pppd. Besides, my ppp interface is dynamic and requires that 
>the routing tables be flushed (or monitored) for sanity's sake.

Hmm, but this rather sounds like a problem with pppd.

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)