safe to remove IPV6 from kernel?

Pekka Savola pekkas at netcore.fi
Tue May 25 20:15:38 UTC 2004


On Mon, 24 May 2004, Chris Ricker wrote:
> On Sun, 23 May 2004, Dax Kelson wrote:
> 
> > Ummm, because it's compiled as a module so you are free to not load it
> > without a kernel recompile.
> > 
> > To prevent the autoloading, run the command:
> > 
> > echo "NETWORKING_IPV6=no" >> /etc/sysconfig/network
> 
> The scripts look like they try to do that, but it doesn't actually work.  
> With "NETWORKING_IPV6=no" in /etc/sysconfig/network, the IPv6 module still
> autoloads and link-local addresses are still automagically assigned.
> 
> I've not yet had time to investigate and see why it's not working.

Well, setting NETWORKING_IPV6=no.

If it's "yes", the scripts add the net-pf-10 -> ipv6 alias to 
modules.conf and start up IPv6.

If it's "no", the scripts do nothing.  If an application tries to set 
up an IPv6 socket:

 1) previously IPv6 ended up being loaded in any case unless you 
commented off net-pf-10 entries from modules.conf

 2) currently, AFAIR when modutils already includes the implicit 
net-pf-10 -> ipv6 mapping internally, even commenting it out doesn't 
help to prevent IPv6 from being loaded.

So, I guess the fix here is that if NETWORKING_IPV6 has been set to
"no", the scripts should remove all the net-pf-10 entries and insert
'alias net-pf-10 off' entry.  

We might also want to do this when NETWORKING_IPV6 is unset, for
consistency, but that's a slighly different scenario.  This is
probably similar if we'd change the implicit default value of
NETWORKING_IPV6 from "no" to "yes".

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings







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