Re: libpcap and tc filters

[Adam Katz <adamkatz0 () gmail com>]

my ip and tcp checksums should be correct, but i'll check it out.
Could you point me in the direction of an ACTIVE mailing list with traffic
shaping guys? The ones I found were pretty much abandoned.

thanks!

On Sun, Jun 5, 2011 at 7:59 PM, Aaron Turner <synfinatic () gmail com> wrote:

> On Sun, Jun 5, 2011 at 12:29 AM, Adam Katz <adamkatz0 () gmail com> wrote:
> > First of all, thanks for the quick reply.
> >
> > Well, I am using Linux, sorry for not mentioning that explicitly. tc is
> the
> > built in linux utility for (among other things) traffic shaping... it's a
> > pretty useful piece of software. I use it to create three output queues
> on
> > eth0 with a scheduler that selects which of them to dequeue. I
> immediately
> > though of the explanation you gave me and imagined pcap might bypass some
> of
> > the stack but it doesn't seem that way as packets sent with pcap do show
> up
> > in those queues I created, they're only not classified correctly and end
> up
> > in the default queue.
> >
> > If pcap was completely bypassing the stack, I imagine i would not have
> seen
> > the packets in the queue at all.
>
> Correct.  If they are getting classified, but not correctly, then I'd
> have to guess that the classification rules you're using don't match
> the traffic.   No idea if it matters, but make sure your IP checksums
> are correct.  When you captured the traffic, outbound traffic may have
> the wrong checksums.
>
> Other then that, may want to ask the traffic shaping guys.
>
>
> --
> Aaron Turner
> http://synfin.net/         Twitter: @synfinatic
> http://tcpreplay.synfin.net/ - Pcap editing and replay tools for Unix &
> Windows
> Those who would give up essential Liberty, to purchase a little temporary
> Safety, deserve neither Liberty nor Safety.
>     -- Benjamin Franklin
> "carpe diem quam minimum credula postero"
> -
> This is the tcpdump-workers list.
> Visit https://cod.sandelman.ca/ to unsubscribe.
-
This is the tcpdump-workers list.
Visit https://cod.sandelman.ca/ to unsubscribe.