Re: questions on -B, performance, mbufs, and

[Rick Jones <rick.jones2 () hp com>]

On 09/27/2011 07:32 PM, Jon Schipp wrote:
> Hello Guy,
>
> I'm now doing testing with tcpdump on an Ubuntu machine.
>
> One difference I noticed was that in addition to "dropped by kernel",
> tcpdump on Ubuntu also reports
> "dropped by interface".
>
> Is this specific to Linux, because I haven't experienced this on FreeBSD? Is
> this Ubuntu distro addendum or has this been added by the tcpdump team.
>
> Where do the numbers come from for the "dropped by interface", you've
> already explained the "dropped by kernel"
> I was just wondering how this differs. Would this be the number reported by
> ifconfig?

If, as the name suggests, those are drops reported by the NIC, 
presumably the value you see being emitted by tcpdump would track rather 
closely with the stats reported for the interface via ethtool -S <interface>

rick jones
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