[CentOS] Performance of CentOS as a NAT gateway

On 9/10/07, John R Pierce <pierce at hogranch.com> wrote:
> wireshark can process and display packet capture files from tcpdump -w
>
> capture a few megabytes of packets on the appropriate interface of the
> firewall, then transfer them to a workstation with Wireshark for analysis.

OK, I've got some output from "tcpdump -w any" but I don't know
precisely what I'm looking for.  (I'd be happy to take this off-list.)
 I notice that just over 1/3 of the packets are TCP out-of-order
segments and about 4% are duplicate ACKs.

We also dumped eth0 and eth1 separately.  Statistics on the "any"
output show 26Mb/s, but eth0 and eth1 independently are only 10Mb/s
each.

By the way, those interrupts/sec numbers in my earlier message were
off; I chose a bad moment to look at it, when the peak had subsided.
At peak it's more like 2500-3000 interrupts/sec, sometimes as high as
3500.