[gentoo-user] Disable IPv6 on an interface?

[gentoo-user] Disable IPv6 on an interface?

[Grant Edwards]

How does one disable IPv6 for a particular interface?

I want eth2 "up" but with no IP address.  Just doing an "ifconfig eth2
up" worked fine until I enabled IPv6 support in the kernel.  Now I get
a link-local IPv6 address just by bringing the interface up -- and I
don't want one.

Google has found me the anser for Debian, but for Gentoo all it found
was somebody else asking the qeustion (with no answers).


-- 
Grant Edwards               grant.b.edwards        Yow! I know things about
                                  at               TROY DONAHUE that can't
                              gmail.com            even be PRINTED!!

Re: [gentoo-user] Disable IPv6 on an interface?

[Paul Hartman]

On Tue, Jan 17, 2012 at 9:48 AM, Grant Edwards
<grant.b.edwards@gmail.com> wrote:
> How does one disable IPv6 for a particular interface?
>
> I want eth2 "up" but with no IP address.  Just doing an "ifconfig eth2
> up" worked fine until I enabled IPv6 support in the kernel.  Now I get
> a link-local IPv6 address just by bringing the interface up -- and I
> don't want one.
>
> Google has found me the anser for Debian, but for Gentoo all it found
> was somebody else asking the qeustion (with no answers).

I didn't try it myself, but what about sysctl?

net.ipv6.conf.eth0.disable_ipv6=1

or something like that...

[gentoo-user] Re: Disable IPv6 on an interface?

[Grant Edwards]

On 2012-01-17, Paul Hartman <paul.hartman+gentoo@gmail.com> wrote:
> On Tue, Jan 17, 2012 at 9:48 AM, Grant Edwards
><grant.b.edwards@gmail.com> wrote:
>> How does one disable IPv6 for a particular interface?
>>
>> I want eth2 "up" but with no IP address. ?Just doing an "ifconfig eth2
>> up" worked fine until I enabled IPv6 support in the kernel. ?Now I get
>> a link-local IPv6 address just by bringing the interface up -- and I
>> don't want one.
>>
>> Google has found me the anser for Debian, but for Gentoo all it found
>> was somebody else asking the qeustion (with no answers).
>
> I didn't try it myself, but what about sysctl?
>
> net.ipv6.conf.eth0.disable_ipv6=1
>
> or something like that...

That does it!

The next question is what do I put in the Gentoo network configuration
file (/etc/conf.d/net) to get that result (eth2 up with no IP
addresses).

-- 
Grant Edwards               grant.b.edwards        Yow! Like I always say
                                  at               -- nothing can beat
                              gmail.com            the BRATWURST here in
                                                   DUSSELDORF!!

Re: [gentoo-user] Re: Disable IPv6 on an interface?

[Michael Mol]

Grant Edwards wrote:
> On 2012-01-17, Paul Hartman <paul.hartman+gentoo@gmail.com> wrote:
>> On Tue, Jan 17, 2012 at 9:48 AM, Grant Edwards
>> <grant.b.edwards@gmail.com> wrote:
>>> How does one disable IPv6 for a particular interface?
>>>
>>> I want eth2 "up" but with no IP address. ?Just doing an "ifconfig eth2
>>> up" worked fine until I enabled IPv6 support in the kernel. ?Now I get
>>> a link-local IPv6 address just by bringing the interface up -- and I
>>> don't want one.
>>>
>>> Google has found me the anser for Debian, but for Gentoo all it found
>>> was somebody else asking the qeustion (with no answers).
>>
>> I didn't try it myself, but what about sysctl?
>>
>> net.ipv6.conf.eth0.disable_ipv6=1
>>
>> or something like that...
> 
> That does it!
> 
> The next question is what do I put in the Gentoo network configuration
> file (/etc/conf.d/net) to get that result (eth2 up with no IP
> addresses).
> 

/etc/sysctl.conf

net.ipv6.conf.eth0.disable_ipv6=1

It may be sufficient to just use:
net.ipv6.conf.eth0.autoconf=0
net.ipv6.conf.eth0.accept_ra=0

I'm just guessing that .autoconf corresponds to link-local addresses,
though.

Re: [gentoo-user] Re: Disable IPv6 on an interface?

[Pandu Poluan]

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On Jan 17, 2012 11:56 PM, "Grant Edwards" <grant.b.edwards@gmail.com> wrote:
>
> On 2012-01-17, Paul Hartman <paul.hartman+gentoo@gmail.com> wrote:
> > On Tue, Jan 17, 2012 at 9:48 AM, Grant Edwards
> ><grant.b.edwards@gmail.com> wrote:
> >> How does one disable IPv6 for a particular interface?
> >>
> >> I want eth2 "up" but with no IP address. ?Just doing an "ifconfig eth2
> >> up" worked fine until I enabled IPv6 support in the kernel. ?Now I get
> >> a link-local IPv6 address just by bringing the interface up -- and I
> >> don't want one.
> >>
> >> Google has found me the anser for Debian, but for Gentoo all it found
> >> was somebody else asking the qeustion (with no answers).
> >
> > I didn't try it myself, but what about sysctl?
> >
> > net.ipv6.conf.eth0.disable_ipv6=1
> >
> > or something like that...
>
> That does it!
>
> The next question is what do I put in the Gentoo network configuration
> file (/etc/conf.d/net) to get that result (eth2 up with no IP
> addresses).
>

You don't.

Put it in /etc/sysctl.conf instead.

Rgds,

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[gentoo-user] Re: Disable IPv6 on an interface?

[Grant Edwards]

On 2012-01-17, Michael Mol <mikemol@gmail.com> wrote:

>>> net.ipv6.conf.eth0.disable_ipv6=1

>> The next question is what do I put in the Gentoo network configuration
>> file (/etc/conf.d/net) to get that result (eth2 up with no IP
>> addresses).
>> 
>
> /etc/sysctl.conf
>
> net.ipv6.conf.eth0.disable_ipv6=1

Well that's just too simple and obvious.  I put a sysctl command in a
preup() function in conf.d/net, and that worked, but it's definitly
the wrong way to do it.

After putting the above line in sysctl.conf (and removing my preup()
function), everything worked as expected except that I had to manually
start the interface with the command "/etc/init.d/net.eth2 start".

Google told me to fix that by using rc-update to add net.eth2 to the
default runlevel.

Everything's tickety-boo now, but I don't remember have to do that
last step in the past when I added a network interface -- all I had to
do was create the symlink from net.<whatever> to net.lo.

Is the rc-update runlevel stuff new?

-- 
Grant Edwards               grant.b.edwards        Yow! BARBARA STANWYCK makes
                                  at               me nervous!!
                              gmail.com            

Re: [gentoo-user] Re: Disable IPv6 on an interface?

[Paul Hartman]

On Tue, Jan 17, 2012 at 11:50 AM, Grant Edwards
<grant.b.edwards@gmail.com> wrote:
> After putting the above line in sysctl.conf (and removing my preup()
> function), everything worked as expected except that I had to manually
> start the interface with the command "/etc/init.d/net.eth2 start".
>
> Google told me to fix that by using rc-update to add net.eth2 to the
> default runlevel.
>
> Everything's tickety-boo now, but I don't remember have to do that
> last step in the past when I added a network interface -- all I had to
> do was create the symlink from net.<whatever> to net.lo.
>
> Is the rc-update runlevel stuff new?

AFAIR you've had to do it that way forever... but it's not exactly
something I set up every day.

Maybe if you used ifplugd, wicd, networkmanager etc. it works differently.