IP_FORWARD /etc/sysconfig/network magic words?

[Jeff Kinz]

On Fri, Apr 29, 2005 at 03:01:16PM -0400, Jeff Kinz wrote:
> In the file /etc/sysconfig/network, does the line :
> 
> FORWARD_IPV4=YES
> 
> actually control IP forwarding?  Currently my system seems to be
> ignoring it.  ie - I font actually get any ip-forwarding happening when
> the network is up unless I explicitly enable it.

Aha!  
Google - almost as powerful as Rick Stevens!

https://www.redhat.com/archives/redhat-list/2001-May/msg01047.html
indicates:

########################### QUOTE ###############################
I do not thing that forward_ipv4="yes" works any more.  The settings in
sysctl.conf are used instead.

Look at /etc/sysctl.conf.  Forward_ipv4 is one of the things normaly
controlled by this config file.  You may also want to look at the sysctl
command - it is a cleaner way to change the settings then using echo.

########################### END QUOTE ###############################

In /etc/sysctl.conf:
net.ipv4.ip_forward = 0  

appears to disable forwarding.

What are the security implications of changing "0" to "1" in this line?

At system boot time, will the /etc/sysconfig/iptables file info be
processed significantly later than the /etc/sysctl.conf info?

If that is true, then do we have insecure window of time where 
the system will automatically forward packets anywhere? 

Is this significant?


-- 
Jeff Kinz, Emergent Research, Hudson, MA.