From mboxrd@z Thu Jan  1 00:00:00 1970
From: Patrick McHardy <kaber@trash.net>
Subject: Re: netfilter/iptables and network interface names
Date: Fri, 05 Feb 2010 11:27:32 +0100
Message-ID: <4B6BF294.3020501@trash.net>
References: <4B6AC467.7020209@redhat.com> <alpine.LSU.2.01.1002041528300.13435@obet.zrqbmnf.qr> <4B6ADA3A.7040201@trash.net> <alpine.LSU.2.01.1002041542150.13435@obet.zrqbmnf.qr> <4B6ADFFB.4050407@trash.net> <alpine.LSU.2.01.1002041743360.21982@obet.zrqbmnf.qr> <4B6AFAA1.5080703@trash.net> <alpine.LSU.2.01.1002041944120.30159@obet.zrqbmnf.qr>
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Cc: Thomas Woerner <twoerner@redhat.com>, netdev@vger.kernel.org,
	Netfilter Developer Mailing List
	<netfilter-devel@vger.kernel.org>
To: Jan Engelhardt <jengelh@medozas.de>
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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.