[VLAN] dropping of un-matched tagged packets?
|[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]|
Hello, I've observed a behaviour of Linux VLAN support that surprises me, but, given that I'm not an expert :) I would like to describe it in this list, just to know if it is the expected behaviour. It seems that when a 802.1q tagged packet is received in a physical Linux interface (for example 'eth2') the behaviour is: 1. If there is some subinterface maching the tag, the packet is deliver to that interface. For example, if the packet is tagged with VLANID=200 and there is an eth2.200 interface, the packet is delivered to eth2.200 (and a 'tcpdump -i eth2.200', for example, would show it). 2. If there is no subinterface maching the tag, the packet is drop. For example, if the packet is tagged with VLANID=300 and there is no eth2.300, the packet is drop (and a 'tcpdump -i eth2' would never show it). Is that right? In that case, I would like to know if is possible to change the behaviour of item 2 (maybe with some configuration in the /proc/sys hierarchy), so a 'tcpdump -i eth2' shows the tagged packet. I'm asking this beacuse I would like to bridge a trunk of tagged traffic (that comes at eth2 from/to a Cisco router) with a software bridge in the Linux box implemeted with brctl ('brctl addif somebridge eth2') , but if the default behaviour is to drop tagged un-matched packets, this seems imposible... Any help and related information it's very welcome. Thanks in advance! Best regards, -------------------- Ferm?n Gal?n M?rquez CTTC - Centre Tecnol?gic de Telecomunicacions de Catalunya Parc Mediterrani de la Tecnologia, Av. del Canal Ol?mpic s/n, 08860 Castelldefels, Spain Room 1.02 Tel : +34 93 645 29 12 Fax : +34 93 645 29 01 Email address: fermin.galan@xxxxxxx
[Netdev] [Ethernet Bridging] [Linux Wireless] [Kernel Newbies] [Security] [Linux for Hams] [Netfilter] [Bugtraq] [Photo] [Yosemite] [Yosemite News] [MIPS Linux] [ARM Linux] [Linux RAID] [Linux Admin] [Samba] [Video 4 Linux] [Linux Resources]