Re: Intel X520-SR2 not seeing packets in tcpdump
Guy Harris <guy <at> alum.mit.edu>
2012-03-01 23:54:14 GMT
On Mar 1, 2012, at 3:39 PM, Mark W. Jeanmougin wrote:
> On Thu, Mar 1, 2012 at 11:55, Charles DeVoe <scarecrow_57 <at> yahoo.com> wrote:
>> I have installed an X520 card with the latest driver ixgbe 3.8. The operating systems is CentOS 5.7. When
doing an ifconfig I see receive packets. I also see packets when I do an ethtool -S p1p2. However, when I do
tcpdump -i p1p2 I see no packets. Does anyone know why this may be happening.
> I've got some experience with the X520 cards under various flavors of
> Linux. I've always had good luck. Although, they do require a bit more
> care and feeding than a Copper e1000. Can you be a bit more specific
> about what you're seeing?
> The other thing I'll throw out there: Do you have vlan tags set on
> these packets? If so, you need to add the "vlan" option to tcpdump.
That should only be necessary if you're capturing with a filter; if the command is just
tcpdump -i p1p2
then no filter was specified, so "vlan" shouldn't be necessary and will, in fact, *reduce* the number of
packets (as it'll mean capturing only packets with VLAN tags).
"vlan" is used when its side-effect, of causing other filters to go past the VLAN tag and look at the actual
Ethernet type field, is desired, e.g. if you have tagged packets, "host foobar" won't work as it won't
recognize IPv4 or IPv6 packets, you'd need either