Hello All,
I am assisting a professor at my university to setup a few machines for a security course he teaches. There are pre-written scripts he has taken from another course that use nemesis to scan an external machine on a 128. network from a machine behind a firewall in a 10. network. Whenever we run the scan script using packet injection, everything seems fine (i.e. The target machine is capturing the sent packets) however nemesis spits this out many times:

ERROR: Incomplete packet injection. Only wrote -1 bytes.

Now, even if I append ">/dev/null" to the command line, or "1>/dev/null 2>/dev/null", nemesis still gives the error message. The professor is OK with just getting rid of the error message, since he does see everything recieved anyway on the target machine. I found the source for the "buildarp" method in nemesis that actually throws the error message.

Oh yes, and here is the actual command line the script is using to execute nemesis:

nemesis-tcp -I 444 -T 99 -a 111 -s 222 -w 333 -fS -FD -x 0 -y 11 -D 128.226.1.50 -S 192.168.50.32 1>/dev/null 2>/dev/null

My question is, why is nemesis writing this error? And... How can I get it to execute without spitting the error out, short of modifying the source?

Thank you very much in advance.

I'm doing fine with the latest version of Nemesis and the suggested Libnet version. Maybe recompile? Nemesis is kinda stale though (2003). Could retry with something more recent and a more recent Libnet?

Yeah, I think what I'm going to end up doing is just recompiling anyway. We've got to stick with nemesis though, cause the professor really seems to like it and has grown familiar with it through this project.

Only problem I have now is how to get the nemesis source onto the VMWare machine that I am running linux from. Gotta figure out either how to get VMWare to allow the NAT to pass through to the actual system hardware, or get a floppy/CD/USB Key through. But that's another issue.

Thanks very much for the reply!
Cheers!