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Date: Fri, 19 Sep 2008 13:37:34 -0700
From: Maxim Sobolev <sobomax@FreeBSD.org>
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To: Alexey Shuvaev <shuvaev@physik.uni-wuerzburg.de>
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Cc: freebsd-current@FreeBSD.org, Maksim Yevmenkin <maksim.yevmenkin@gmail.com>
Subject: Re: Interface auto-cloning bug or feature?
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Alexey Shuvaev wrote:
> On Fri, Sep 19, 2008 at 04:33:19AM -0700, Maxim Sobolev wrote:
>> Alexey Shuvaev wrote:
>>>> [root@sp1 /usr/home/sobomax]# ifconfig -a
>>>> tun0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
>>>> tun1: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
>>>> tun2: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
>>>> tun3: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
>>>>
>>> Me too.
>>> I have seen that using ppp(8) and security/vpnc.
>> That what has caused me to look into this issue. You can find patch for  
>> security/vpnc to prevent unbounded interface cloning here:
>>
>> http://sobomax.sippysoft.com/~sobomax/vpnc.diff
>>
> Ok, the patch prevents interface cloning, but I think it doesn't solve
> the actual problem.

Well, in any case checking kernel modules list to detect if_tun presence 
is more correct way than doing stat on /dev/tun.

-Maxim