Subject: Re: netfilter/iptables and network interface names

From: Patrick McHardy <[email-masked]>
Date: Fri, 05 Feb 2010 11:27:32 +0100

Jan Engelhardt wrote:
> On Thursday 2010-02-04 17:49, Patrick McHardy wrote:
>> Jan Engelhardt wrote:
>>>> The kernel also forbids ".".
>>> My first thought was the same, but:
>>>
>>> a) Interestingly, it does not prohibit '.'
>>>
>>> 	ip tunnel add foo0.3 mode sit local 1.2.3.4 remote 5.6.7.8
>>>
>>> b) The '.' is to be seen as valid as far as xtables.c goes, so
>>>    as to match VLAN interfaces.
>> Ah of course, its only invalid at the beginning of the name.
>>
> Nope:
> 
> 19:44 borg:/home/jengelh # ip tunnel add .3 mode sit local 1.2.3.6 remote
> 5.6.7.7
> 19:44 borg:/home/jengelh # ip a
> 17: .3: <POINTOPOINT,NOARP> mtu 1480 qdisc noop state DOWN 
>     link/sit 1.2.3.6 peer 5.6.7.7

OK you're right, but this seems to be an oversight. The names
are checked during rename, but not on device registration.