From: Jonathan Tripathy <jonnyt@abpni.co.uk>
To: John Haxby <john.haxby@oracle.com>
Cc: netfilter@vger.kernel.org
Subject: Re: VLANs
Date: Tue, 11 Jan 2011 10:57:37 +0000 [thread overview]
Message-ID: <4D2C37A1.8090906@abpni.co.uk> (raw)
In-Reply-To: <4D2C3426.3000202@oracle.com>
> On 10/01/11 22:15, Jonathan Tripathy wrote:
>> If a guest maliciously added a vlan tag, wouldn’t it still remain in
>> the frame, however be "double-tagged" by the outgoing physical port?
>> Even still though, this probably isn't an issue, provided that all
>> upstream switches are configured correctly.
>
> I don't believe that this is an issue. And 802.1ad double tag won't
> be recognised so it will either be dropped by the switch or dropped by
> the outgoing NIC on the bridge. Short of constructing frames by
> hand, though, I'm not sure how you would go about adding an 802.1ad
> vlan tag on top of an 802.1q vlan tag.
>
I wish it wasn't an issue. Many switches allow hosts to vlan hop if the
native vlan of a trunk port is the same as the native vlan of the host.
It's eaisly prevent t hough with proper switch configuration.
What ebtable command would I use to prevent *any* tagged frames coming
from a host?
next prev parent reply other threads:[~2011-01-11 10:57 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-10 17:42 VLANs Jonathan Tripathy
2011-01-10 21:33 ` VLANs John Haxby
2011-01-10 22:15 ` VLANs Jonathan Tripathy
2011-01-11 8:19 ` VLANs Thomas Berg
2011-01-11 10:26 ` VLANs Jonathan Tripathy
2011-01-11 10:42 ` VLANs John Haxby
2011-01-11 10:57 ` Jonathan Tripathy [this message]
[not found] ` <4D2C47DB.10702@oracle.com>
2011-01-11 12:24 ` VLANs Jonathan Tripathy
2011-01-11 12:48 ` VLANs John Haxby
2011-01-11 12:52 ` VLANs Jonathan Tripathy
2011-01-11 17:12 ` VLANs John Haxby
2011-01-11 17:15 ` VLANs Jonathan Tripathy
2011-01-11 17:21 ` VLANs John Haxby
-- strict thread matches above, loose matches on Subject: below --
2011-01-05 12:12 VLANs Jonathan Tripathy
2011-01-06 7:32 ` VLANs John Haxby
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