Re: dropping of un-matched tagged packets?
Ben Greear <[email protected]>
| Newsgroups | gmane.linux.drivers.vlan |
|---|---|
| Organization | Candela Technologies |
| Message-ID | <[email protected]> |
Fermín Galán Márquez wrote: > 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). I would expect you to see the packet on eth2, but many NICs handle VLANs in the NIC driver/hardware now, so maybe the NIC won't even pass the frame up if the VLAN is not configured? Ben -- Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com