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Date:      Sun, 31 Dec 2006 07:20:43 -0200
From:      JoaoBR <joao@matik.com.br>
To:        Sam Leffler <sam@errno.com>
Cc:        freebsd-stable@freebsd.org
Subject:   Re: ath0 timeout problem - again
Message-ID:  <200612310720.43293.joao@matik.com.br>
In-Reply-To: <45972EF6.9040506@errno.com>
References:  <200612282002.11562.joao@matik.com.br> <200612301926.57736.joao@matik.com.br> <45972EF6.9040506@errno.com>

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On Sunday 31 December 2006 01:31, Sam Leffler wrote:
> >>> I really do not know what this event means (ether type 5e4), for my
> >>> understandings it is vague in the source, so I am lost here
> >>
> >> Seems pretty clear: it's the type field extracted from the ethernet
> >> header of the oversized packet. =A0A quick check of sys/net/ethernet.h
> >> shows no such ETHERTYPE defined. =A0So something in your network is
> >> transmitting packets that either being rx'd incorrectly or, more likel=
y,
> >> corrupted in transit.
> >
> > good so far, point here is that we can not limit that someone tx this
> > kind of packets but should find a way that this traffic do not DoS the
> > AP.
> >
> > ipfw accepts 0x5e4 but at the end it does not get this packages
> > changing mtu on any interface does not change a thing
> >
> >
> > when we track the oversized packages they we found they are coming from
> > nat servers where wingate and similar softwares are running, when we cut
> > them out the mentioned traffic stopps and the AP does not interrupt
> > service anymore
>
> So the packet is real and it's being dropped at the 802.3 layer as it
> should. =A0If the printf is the problem remove it or rate limit it. =A0I
> think it should be rate-limited or just stuck under a debug flag but
> I'll leave that to someone else. =A0Alternatively we can enforce the mtu
> in the ath driver and drop it there.

the problem is that the ath card stops working rendering the machine useless

I do not get this problem with a wi prism card, when I switch to a wi card =
I=20
get some wi timeout events but the card does not stop as the ath does

when I run the server with ath card not as bridge but as a gateway it also=
=20
does not stop working and the mentioned packages do also exist on the netwo=
rk=20
but are not even mentioned/noticed by the AP

enforcing a mtu limit and dropping the larger packages sounds as a good sta=
rt=20
for me. If you could be so kind and make such a patch to try it out I get t=
he=20
results in a day or two since I have machines which hang several times a da=
y.


=2D-=20

Jo=E3o







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