Re: vlan [xx] filter not filtering any packets

[Nikola Ciprich <extmaillist () linuxbox cz>]

Hi Michael,
saving the traffic to file first and trying the filter while loading the
dump works. Same case when trying vlan filtering in virtual hosts using
virtio interface, so the problem must be related to vlan acceleration somehow.
But I though that for 2.6.29 vlan acceleration should be disabled while switching to
promisc mode, do You have any ideas?
thanks
nik


On Mon, Jun 08, 2009 at 12:08:09PM -0400, Michael Richardson wrote:
> > > > > > "Nikola" == Nikola Ciprich <extmaillist () linuxbox cz> writes:
>     Nikola> Hello,
>
>     Nikola> I've spent some time playing with tcpdump and pcap with
>     Nikola> regard to vlans. Using libpcap 1.0.0 + tcpdump 4.0.0, I can
>     Nikola> able to correctly dump packets including (reconstructed)
>     Nikola> vlan headers. But it seems that using the vlan filter
>     Nikola> keyword does not work.
>
>     Nikola> example: $ tcpdump -e -i eth1 13:10:05.592027
>     Nikola> 00:30:48:92:f6:73 (oui Unknown) > 00:30:48:64:40:9d (oui
>     Nikola> Unknown), ethertype 802.1Q (0x8100), length 102: vlan 10, p
>     Nikola> 0, ethertype IPv4, 10.0.10.1 > 10.0.10.2: ICMP echo request,
>     Nikola> id 27941, seq 12466, length 64
>
>     Nikola> which is OK. But
>
>   Can you capture the data to a .pcap file, and reproduce it with -r?
>   If so, then a test case could be added.
>
>   I suspect that the vlan filter may not work if there is further SNAP
> headers, but that's just top of my head idea..
>
> -- 
> ]     Y'avait une poule de jammé dans l'muffler!!!!!!!!!        |  firewalls  [
> ]   Michael Richardson, Sandelman Software Works, Ottawa, ON    |net architect[
> ] mcr () sandelman ottawa on ca http://www.sandelman.ottawa.on.ca/ |device driver[
> ]    h("Just another Debian GNU/Linux using, kernel hacking,    ruby  guy");  [
>
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