IP-Forwarding

[Eric Hines]

I'm running FC3 2.6.11-1.35_FC3 on a server motherboard with 2 NICs.  
I've been advised that to have IP forwarding (e.g., between subnets off 
those NICs (I'll add a third NIC for Internet access), I must add the 
command

    echo 1 > /proc/sys/net/ipv4/ip_forward

to the /etc/rc.d/boot.local.  This person also advises that "I may want 
to do the echo command last and include "0" in the init scripts, since 
it opens up your network for a short time."  But he's a SuSE guru, not a 
Fedora Core guru.

My questions are these:  a) is this really necessary, or does the kernel 
already include IP forwarding built in?
    b) As FC3 does not have a boot.local file, where would I put this 
command, if it is, in fact, necessary? At the end of 
/etc/rc.d/init.d/xinetd, just ahead of the exit $RETVAL?  Just after 
exit $RETVAL?
    c) What about that 0?  Where, specifically, should it go?

Thanks for your help.

Eric Hines

-- 
He can compress the most words into the smallest ideas of any man
I ever met.
  - Abraham Lincoln