Networking problem

[JD]

On 05/19/11 18:45, Tom H wrote:
> On Thu, May 19, 2011 at 8:57 PM, JD<jd1008 at gmail.com>  wrote:
>> On 05/19/11 17:41, Tom H wrote:
>
>>> To the OP: Do you have a "/etc/sysconfig/network-scripts/ifcfg-wlan0"
>>> and a "/etc/sysconfig/network-scripts/ifcfg-wlan0:0"? What are their
>>> contents?
>> I have no  /etc/sysconfig/network-scripts/ifcfg-wlan0:0
>>
>> $ cat /etc/sysconfig/network-scripts/ifcfg-wlan0:
>> DEVICE=wlan0:0
>> IPV6INIT=no
> Why do you have "DEVICE=wlan0:0" in
> "/etc/sysconfig/network-scripts/ifcfg-wlan0"?
>
>
I think that is a remnant. Thank for pointing it out.
I had completely overlooked it. But, it is nevertheless,
harmless.

>>>> It is a valid IPv6 interface.
>>> It's valid but it isn't routable. It's the equivalent of an ipv4
>>> 169.254.x.y address.
>> Yes. ifconfig always prints this even when ip6 is disabled.
> No, if ipv6 is disabled, no ipv6 address is assigned to any interface.
I do not see in any of my conf files, nor in services
where I have enabled ipv6.
But I think there are other internal interfaces/modules that, [do 
not/are not configured to]
go out over the LAN, that use ipv6: such as:
bridge,ah6,esp6,xfrm6_mode_beet,xfrm6_mode_tunnel,ipcomp6,xfrm6_tunnel,tunnel6

But I see your point because I thought that it was completely disabled.
Now I wonder if any of the loadable modules that get loaded, depend on.
ipv6 being enabled.

>
>>>> The fact that IPv6 layer was disabled on the subnet (as JD clarified it later),
>>>> does not change anything. Once again, the type of configured interface wlan0
>>>> is of interest to me, that is IPv6-type.
>>> Since wlan0:0 has a ipv6 address, ipv6 must not be disabled.
>> It really IS disabled. Look at the contents of my ifcfg-wlan0 above.
>> It says IPV6INIT=no
> "IPV6INIT=no" doesn't disable ipv6; it's used by
> "/etc/sysconfig/network-scripts/ifup-ipv6" to determine whether to
> configure ipv6 for that interface. If ipv6.ko isn't prevented from
> loading through "/etc/modprobe.conf" or a conf file in
> "/etc/modprobe.conf.d/", an interface will be assigned an fe80 ipv6
> address.
Correct. I had overlooked that altogether.
As I asked above, I wonder if some service will break
if I black list the ipv6 modules.