Re: [gentoo-user] Disable IPv6 on specific interface

[Mick <michaelkintzios@gmail.com>]

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On Tuesday 30 Dec 2014 10:10:04 Zesen Qian wrote:
> Mick <michaelkintzios@gmail.com> writes:
> > On Tuesday 30 Dec 2014 03:27:34 Zesen Qian wrote:
> >> Hello list,
> >> Sorry for hijacking Rich's thread, resend here.
> >> I want to disable IPv6 on an certain interface, a simple google
> >> tell me to add one line to /etc/sysctl.d/local.conf
> >> net.ipv6.conf.enp4s0.disable_ipv6=1
> >> Simple enough, but the problem I have is that both ipv6 and the
> >> dirver of the network card(tg3) is loaded by modules. They 're not
> >> loaded when the service sysctl is started, so there's no entry
> >> named "net.ipv6.conf.enp4s0", which make sysctl not working.
> >> So my question is that, is there any way to disable IPv6 on
> >> specific interface, as early as I can? I want to make it early
> >> because I don't want to receive any RA to mess up my route table.
> >> I guess just adding sysctl to preup() in /etc/conf.d/net should do
> >> the trick, but may I make it earlier?
> >> Any comment is appreciated.
> > 
> > Unless the kernel knows of the enp4s0 interface and therefore lists it
> > under sysctl, I can't see how it can be disabled.  You could try
> > disabling IPv6 altogether in the kernel, but this may not be what you
> > want to achieve.
> > 
> > Alternatively, have a look with modinfo in the module options in the
> > unlikely chance that the module has some option which disables IPv6
> > functionality.
> 
> Hello Mick,
> The module ipv6 has only three parameters, each of which is "disable
> ipv6", "disable ipv6 on all interfaces", "disable autoconf on all
> interfaces", none of these is what I want to achieve. 

Right, I didn't think that you would want to disable IPv6 completely, but 
mentioned it for completeness.


> Module tg3 has
> only on parameters which control the debug level.

Yes, I thought it unlikely that a hardware driver would be used to configure 
IPv6, but it was worth checking.


> Currently I just call "sysctl net.ipv6.conf.enp4s0.disable_ipv6=1" in
> preup(), which works just fine. I 'm just wondering if there 's some
> more "proper" way to do it. Since in my opinion, this should be done at
> the first moment when the interface is present, not when the interface
> is up.

I'm afraid I don't know of any other way to do it.

-- 
Regards,
Mick

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