Thank you for your help. First off, there are no samples that I could find -
there were none included with the libnet on my system (installed from a FC3
rpm), nor could I find any via google. Where are they located? I relied on
reading other people's code that was written with libnet, but it was often
not applicable and I had to experiment around.
Using the tcpdump arguments that you recommended, I was able to see that you
were right - the dest hw address was in fact incorrect, and this is
undoubtedly the problem. I was passing it the hw address reported on the
destination machine by ifconfig for my tests using LIBNET_LINK; however, some
other, unknown hw address was being sent when they were built with
LIBNET_RAW4, which was making it to the destination. Is there a simple
function to look up the MAC address, or will I need to build and send the ARP
packets myself? I suppose it's in the samples.
Again, thank you for your help; it is greatly appreciated.
- Karen
On Monday 17 January 2005 10:10 am, you wrote:
Well without any code, all I can say is you're doing something wrong.
First, it doesn't look like that you used the -e or -XX/-xx flag with
tcpdump to print the ethernet header to know where the packets are
actually going to. However, I can make a guess:
LIBNET_RAW4 will cause an ARP request to be made on your behalf to look
up the destination MAC address. The ethernet header of the built
packet will then go to the correct address.
LIBNET_LINK does NOT do an ARP request and expects you to provide the
dst MAC. I'd guess that you put in the wrong dst MAC and hence it
isn't delivered to the target host.
If you have other questions, you might want to check in the "samples"
directory for how to build packets with the LIBNET_LINK API.
