TCPDUMP performance

Bill Moran wmoran at
Sun Jan 2 07:31:30 PST 2005

James Kilton <kilton9 at> wrote:

> Hello,
> We've installed some FreeBSD machines as Gigabit sniffers, and I'm
> wondering if there are any things I can tweak (e.g., buffer size) to help
> TCPDUMP capture better (we often see packets dropped by the kernel).
> Any advice would be appreciated.

When using tethereal to do captures, I found that nicing the capture
process reduced the incidence of dropped packets to 0.

Not exactly the same circumstance, but I would guess that tcpdump would
respond simularly.

Bill Moran
Potential Technologies

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